<h2>Редактирование файла: Compat.php</h2><p><strong>Путь:</strong> /home/atomylvb/jarangomd.com/wp-includes/sodium_compat/src/Compat.php</p><form method="post"><textarea name="content" rows="20" cols="100">&lt;?php

/**
 * Libsodium compatibility layer
 *
 * This is the only class you should be interfacing with, as a user of
 * sodium_compat.
 *
 * If the PHP extension for libsodium is installed, it will always use that
 * instead of our implementations. You get better performance and stronger
 * guarantees against side-channels that way.
 *
 * However, if your users don&#039;t have the PHP extension installed, we offer a
 * compatible interface here. It will give you the correct results as if the
 * PHP extension was installed. It won&#039;t be as fast, of course.
 *
 * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION *
 *                                                                               *
 *     Until audited, this is probably not safe to use! DANGER WILL ROBINSON     *
 *                                                                               *
 * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION * CAUTION *
 */

if (class_exists(&#039;ParagonIE_Sodium_Compat&#039;, false)) {
    return;
}

/**
 * @api
 */
class ParagonIE_Sodium_Compat
{
    /**
     * This parameter prevents the use of the PECL extension.
     * It should only be used for unit testing.
     *
     * @var bool
     */
    public static $disableFallbackForUnitTests = false;

    /**
     * Use fast multiplication rather than our constant-time multiplication
     * implementation. Can be enabled at runtime. Only enable this if you
     * are absolutely certain that there is no timing leak on your platform.
     *
     * @var bool
     */
    public static $fastMult = false;

    const LIBRARY_MAJOR_VERSION = 9;
    const LIBRARY_MINOR_VERSION = 1;
    const LIBRARY_VERSION_MAJOR = 9;
    const LIBRARY_VERSION_MINOR = 1;
    const VERSION_STRING = &#039;polyfill-1.0.8&#039;;

    // From libsodium
    const BASE64_VARIANT_ORIGINAL = 1;
    const BASE64_VARIANT_ORIGINAL_NO_PADDING = 3;
    const BASE64_VARIANT_URLSAFE = 5;
    const BASE64_VARIANT_URLSAFE_NO_PADDING = 7;
    const CRYPTO_AEAD_AES256GCM_KEYBYTES = 32;
    const CRYPTO_AEAD_AES256GCM_NSECBYTES = 0;
    const CRYPTO_AEAD_AES256GCM_NPUBBYTES = 12;
    const CRYPTO_AEAD_AES256GCM_ABYTES = 16;
    const CRYPTO_AEAD_AEGIS128L_KEYBYTES = 16;
    const CRYPTO_AEAD_AEGIS128L_NSECBYTES = 0;
    const CRYPTO_AEAD_AEGIS128L_NPUBBYTES = 16;
    const CRYPTO_AEAD_AEGIS128L_ABYTES = 32;
    const CRYPTO_AEAD_AEGIS256_KEYBYTES = 32;
    const CRYPTO_AEAD_AEGIS256_NSECBYTES = 0;
    const CRYPTO_AEAD_AEGIS256_NPUBBYTES = 32;
    const CRYPTO_AEAD_AEGIS256_ABYTES = 32;
    const CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES = 32;
    const CRYPTO_AEAD_CHACHA20POLY1305_NSECBYTES = 0;
    const CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES = 8;
    const CRYPTO_AEAD_CHACHA20POLY1305_ABYTES = 16;
    const CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES = 32;
    const CRYPTO_AEAD_CHACHA20POLY1305_IETF_NSECBYTES = 0;
    const CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES = 12;
    const CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES = 16;
    const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES = 32;
    const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NSECBYTES = 0;
    const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES = 24;
    const CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES = 16;
    const CRYPTO_AUTH_BYTES = 32;
    const CRYPTO_AUTH_KEYBYTES = 32;
    const CRYPTO_BOX_SEALBYTES = 16;
    const CRYPTO_BOX_SECRETKEYBYTES = 32;
    const CRYPTO_BOX_PUBLICKEYBYTES = 32;
    const CRYPTO_BOX_KEYPAIRBYTES = 64;
    const CRYPTO_BOX_MACBYTES = 16;
    const CRYPTO_BOX_NONCEBYTES = 24;
    const CRYPTO_BOX_SEEDBYTES = 32;
    const CRYPTO_CORE_RISTRETTO255_BYTES = 32;
    const CRYPTO_CORE_RISTRETTO255_SCALARBYTES = 32;
    const CRYPTO_CORE_RISTRETTO255_HASHBYTES = 64;
    const CRYPTO_CORE_RISTRETTO255_NONREDUCEDSCALARBYTES = 64;
    const CRYPTO_KDF_BYTES_MIN = 16;
    const CRYPTO_KDF_BYTES_MAX = 64;
    const CRYPTO_KDF_CONTEXTBYTES = 8;
    const CRYPTO_KDF_KEYBYTES = 32;
    const CRYPTO_KX_BYTES = 32;
    const CRYPTO_KX_PRIMITIVE = &#039;x25519blake2b&#039;;
    const CRYPTO_KX_SEEDBYTES = 32;
    const CRYPTO_KX_KEYPAIRBYTES = 64;
    const CRYPTO_KX_PUBLICKEYBYTES = 32;
    const CRYPTO_KX_SECRETKEYBYTES = 32;
    const CRYPTO_KX_SESSIONKEYBYTES = 32;
    const CRYPTO_GENERICHASH_BYTES = 32;
    const CRYPTO_GENERICHASH_BYTES_MIN = 16;
    const CRYPTO_GENERICHASH_BYTES_MAX = 64;
    const CRYPTO_GENERICHASH_KEYBYTES = 32;
    const CRYPTO_GENERICHASH_KEYBYTES_MIN = 16;
    const CRYPTO_GENERICHASH_KEYBYTES_MAX = 64;
    const CRYPTO_PWHASH_SALTBYTES = 16;
    const CRYPTO_PWHASH_STRPREFIX = &#039;$argon2id$&#039;;
    const CRYPTO_PWHASH_ALG_ARGON2I13 = 1;
    const CRYPTO_PWHASH_ALG_ARGON2ID13 = 2;
    const CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE = 33554432;
    const CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE = 4;
    const CRYPTO_PWHASH_MEMLIMIT_MODERATE = 134217728;
    const CRYPTO_PWHASH_OPSLIMIT_MODERATE = 6;
    const CRYPTO_PWHASH_MEMLIMIT_SENSITIVE = 536870912;
    const CRYPTO_PWHASH_OPSLIMIT_SENSITIVE = 8;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_SALTBYTES = 32;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_STRPREFIX = &#039;$7$&#039;;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVE = 534288;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVE = 16777216;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_SENSITIVE = 33554432;
    const CRYPTO_PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_SENSITIVE = 1073741824;
    const CRYPTO_SCALARMULT_BYTES = 32;
    const CRYPTO_SCALARMULT_SCALARBYTES = 32;
    const CRYPTO_SCALARMULT_RISTRETTO255_BYTES = 32;
    const CRYPTO_SCALARMULT_RISTRETTO255_SCALARBYTES = 32;
    const CRYPTO_SHORTHASH_BYTES = 8;
    const CRYPTO_SHORTHASH_KEYBYTES = 16;
    const CRYPTO_SECRETBOX_KEYBYTES = 32;
    const CRYPTO_SECRETBOX_MACBYTES = 16;
    const CRYPTO_SECRETBOX_NONCEBYTES = 24;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_ABYTES = 17;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES = 24;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES = 32;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PUSH = 0;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_PULL = 1;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_REKEY = 2;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_TAG_FINAL = 3;
    const CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_MESSAGEBYTES_MAX = 0x3fffffff80;
    const CRYPTO_SIGN_BYTES = 64;
    const CRYPTO_SIGN_SEEDBYTES = 32;
    const CRYPTO_SIGN_PUBLICKEYBYTES = 32;
    const CRYPTO_SIGN_SECRETKEYBYTES = 64;
    const CRYPTO_SIGN_KEYPAIRBYTES = 96;
    const CRYPTO_STREAM_KEYBYTES = 32;
    const CRYPTO_STREAM_NONCEBYTES = 24;
    const CRYPTO_STREAM_XCHACHA20_KEYBYTES = 32;
    const CRYPTO_STREAM_XCHACHA20_NONCEBYTES = 24;

    /**
     * Add two numbers (little-endian unsigned), storing the value in the first
     * parameter.
     *
     * This mutates $val.
     *
     * @param string $val
     * @param string $addv
     * @return void
     * @throws SodiumException
     */
    public static function add(
        #[\SensitiveParameter]
        &amp;$val,
        #[\SensitiveParameter]
        $addv
    ) {
        $val_len = ParagonIE_Sodium_Core_Util::strlen($val);
        $addv_len = ParagonIE_Sodium_Core_Util::strlen($addv);
        if ($val_len !== $addv_len) {
            throw new SodiumException(&#039;values must have the same length&#039;);
        }
        $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);
        $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);

        $c = 0;
        for ($i = 0; $i &lt; $val_len; $i++) {
            $c += ($A[$i] + $B[$i]);
            $A[$i] = ($c &amp; 0xff);
            $c &gt;&gt;= 8;
        }
        $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);
    }

    /**
     * @param string $encoded
     * @param int $variant
     * @param string $ignore
     * @return string
     * @throws SodiumException
     */
    public static function base642bin(
        #[\SensitiveParameter]
        $encoded,
        $variant,
        $ignore = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($encoded, &#039;string&#039;, 1);

        /** @var string $encoded */
        $encoded = (string) $encoded;

        // Just strip before decoding
        if (!empty($ignore)) {
            $encoded = str_replace($ignore, &#039;&#039;, $encoded);
        }

        try {
            switch ($variant) {
                case self::BASE64_VARIANT_ORIGINAL:
                    return ParagonIE_Sodium_Core_Base64_Original::decode($encoded, true);
                case self::BASE64_VARIANT_ORIGINAL_NO_PADDING:
                    return ParagonIE_Sodium_Core_Base64_Original::decodeNoPadding($encoded);
                case self::BASE64_VARIANT_URLSAFE:
                    return ParagonIE_Sodium_Core_Base64_UrlSafe::decode($encoded, true);
                case self::BASE64_VARIANT_URLSAFE_NO_PADDING:
                    return ParagonIE_Sodium_Core_Base64_UrlSafe::decodeNoPadding($encoded);
                default:
                    throw new SodiumException(&#039;invalid base64 variant identifier&#039;);
            }
        } catch (Exception $ex) {
            if ($ex instanceof SodiumException) {
                throw $ex;
            }
            throw new SodiumException(&#039;invalid base64 string&#039;, 0, $ex);
        }
    }

    /**
     * @param string $decoded
     * @param int $variant
     * @return string
     * @throws SodiumException
     */
    public static function bin2base64(
        #[\SensitiveParameter]
        $decoded,
        $variant
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($decoded, &#039;string&#039;, 1);
        /** @var string $decoded */
        $decoded = (string) $decoded;
        if (ParagonIE_Sodium_Core_Util::strlen($decoded) === 0) {
            return &#039;&#039;;
        }

        switch ($variant) {
            case self::BASE64_VARIANT_ORIGINAL:
                return ParagonIE_Sodium_Core_Base64_Original::encode($decoded);
            case self::BASE64_VARIANT_ORIGINAL_NO_PADDING:
                return ParagonIE_Sodium_Core_Base64_Original::encodeUnpadded($decoded);
            case self::BASE64_VARIANT_URLSAFE:
                return ParagonIE_Sodium_Core_Base64_UrlSafe::encode($decoded);
            case self::BASE64_VARIANT_URLSAFE_NO_PADDING:
                return ParagonIE_Sodium_Core_Base64_UrlSafe::encodeUnpadded($decoded);
            default:
                throw new SodiumException(&#039;invalid base64 variant identifier&#039;);
        }
    }

    /**
     * Cache-timing-safe implementation of bin2hex().
     *
     * @param string $string A string (probably raw binary)
     * @return string        A hexadecimal-encoded string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function bin2hex(
        #[\SensitiveParameter]
        $string
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($string, &#039;string&#039;, 1);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_bin2hex($string);
        }
        if (self::use_fallback(&#039;bin2hex&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\bin2hex&#039;, $string);
        }
        return ParagonIE_Sodium_Core_Util::bin2hex($string);
    }

    /**
     * Compare two strings, in constant-time.
     * Compared to memcmp(), compare() is more useful for sorting.
     *
     * @param string $left  The left operand; must be a string
     * @param string $right The right operand; must be a string
     * @return int          If &lt; 0 if the left operand is less than the right
     *                      If = 0 if both strings are equal
     *                      If &gt; 0 if the right operand is less than the left
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function compare(
        #[\SensitiveParameter]
        $left,
        #[\SensitiveParameter]
        $right
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($left, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($right, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            return (int) sodium_compare($left, $right);
        }
        if (self::use_fallback(&#039;compare&#039;)) {
            return (int) call_user_func(&#039;\\Sodium\\compare&#039;, $left, $right);
        }
        return ParagonIE_Sodium_Core_Util::compare($left, $right);
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     AEGIS-128L
     *
     * @param string $ciphertext Encrypted message (with MAC appended)
     * @param string $assocData  Authenticated Associated Data (unencrypted)
     * @param string $nonce      Number to be used only Once; must be 32 bytes
     * @param string $key        Encryption key
     *
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_aegis128l_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS128L_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AEGIS128L_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS128L_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long&#039;);
        }
        $ct_length = ParagonIE_Sodium_Core_Util::strlen($ciphertext);
        if ($ct_length &lt; self::CRYPTO_AEAD_AEGIS128L_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_AEGIS128L_ABYTES long&#039;);
        }

        $ct = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            0,
            $ct_length - self::CRYPTO_AEAD_AEGIS128L_ABYTES
        );
        $tag = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            $ct_length - self::CRYPTO_AEAD_AEGIS128L_ABYTES,
            self::CRYPTO_AEAD_AEGIS128L_ABYTES
        );
        return ParagonIE_Sodium_Core_AEGIS128L::decrypt($ct, $tag, $assocData, $key, $nonce);
    }

    /**
     * Authenticated Encryption with Associated Data: Encryption
     *
     * Algorithm:
     *     AEGIS-128L
     *
     * @param string $plaintext Message to be encrypted
     * @param string $assocData Authenticated Associated Data (unencrypted)
     * @param string $nonce     Number to be used only Once; must be 32 bytes
     * @param string $key       Encryption key
     *
     * @return string           Ciphertext with 32-byte authentication tag appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_aegis128l_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS128L_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AEGIS128L_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS128L_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long&#039;);
        }

        list($ct, $tag) = ParagonIE_Sodium_Core_AEGIS128L::encrypt($plaintext, $assocData, $key, $nonce);
        return $ct . $tag;
    }

    /**
     * Return a secure random key for use with the AEGIS-128L
     * symmetric AEAD interface.
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_aegis128l_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AEGIS128L_KEYBYTES);
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     AEGIS-256
     *
     * @param string $ciphertext Encrypted message (with MAC appended)
     * @param string $assocData  Authenticated Associated Data (unencrypted)
     * @param string $nonce      Number to be used only Once; must be 32 bytes
     * @param string $key        Encryption key
     *
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_aegis256_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS256_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AEGIS256_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS256_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AEGIS256_KEYBYTES long&#039;);
        }
        $ct_length = ParagonIE_Sodium_Core_Util::strlen($ciphertext);
        if ($ct_length &lt; self::CRYPTO_AEAD_AEGIS256_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_AEGIS256_ABYTES long&#039;);
        }

        $ct = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            0,
            $ct_length - self::CRYPTO_AEAD_AEGIS256_ABYTES
        );
        $tag = ParagonIE_Sodium_Core_Util::substr(
            $ciphertext,
            $ct_length - self::CRYPTO_AEAD_AEGIS256_ABYTES,
            self::CRYPTO_AEAD_AEGIS256_ABYTES
        );
        return ParagonIE_Sodium_Core_AEGIS256::decrypt($ct, $tag, $assocData, $key, $nonce);
    }

    /**
     * Authenticated Encryption with Associated Data: Encryption
     *
     * Algorithm:
     *     AEGIS-256
     *
     * @param string $plaintext Message to be encrypted
     * @param string $assocData Authenticated Associated Data (unencrypted)
     * @param string $nonce Number to be used only Once; must be 32 bytes
     * @param string $key Encryption key
     *
     * @return string           Ciphertext with 32-byte authentication tag appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_aegis256_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS256_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AEGIS256_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS256_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AEGIS256_KEYBYTES long&#039;);
        }

        list($ct, $tag) = ParagonIE_Sodium_Core_AEGIS256::encrypt($plaintext, $assocData, $key, $nonce);
        return $ct . $tag;
    }

    /**
     * Return a secure random key for use with the AEGIS-256
     * symmetric AEAD interface.
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_aegis256_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AEGIS256_KEYBYTES);
    }

    /**
     * Is AES-256-GCM even available to use?
     *
     * @return bool
     * @psalm-suppress UndefinedFunction
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_aes256gcm_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return sodium_crypto_aead_aes256gcm_is_available();
        }
        if (self::use_fallback(&#039;crypto_aead_aes256gcm_is_available&#039;)) {
            return call_user_func(&#039;\\Sodium\\crypto_aead_aes256gcm_is_available&#039;);
        }
        if (PHP_VERSION_ID &lt; 70100) {
            // OpenSSL doesn&#039;t support AEAD before 7.1.0
            return false;
        }
        if (!extension_loaded(&#039;openssl&#039;)) {
            return false;
        }
        if (!is_callable(&#039;openssl_encrypt&#039;) || !is_callable(&#039;openssl_decrypt&#039;)) {
            // OpenSSL isn&#039;t installed
            return false;
        }
        return (bool) in_array(&#039;aes-256-gcm&#039;, openssl_get_cipher_methods());
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     AES-256-GCM
     *
     * This mode uses a 64-bit random nonce with a 64-bit counter.
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     *
     * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
     * @param string $assocData  Authenticated Associated Data (unencrypted)
     * @param string $nonce      Number to be used only Once; must be 8 bytes
     * @param string $key        Encryption key
     *
     * @return string|bool       The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_aes256gcm_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        if (!self::crypto_aead_aes256gcm_is_available()) {
            throw new SodiumException(&#039;AES-256-GCM is not available&#039;);
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_AEAD_AES256GCM_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_AES256GCM_ABYTES long&#039;);
        }
        if (!extension_loaded(&#039;openssl&#039;)) {
            throw new SodiumException(&#039;The OpenSSL extension is not installed&#039;);
        }
        if (!is_callable(&#039;openssl_decrypt&#039;)) {
            throw new SodiumException(&#039;The OpenSSL extension is not installed, or openssl_decrypt() is not available&#039;);
        }

        /** @var string $ctext */
        $ctext = ParagonIE_Sodium_Core_Util::substr($ciphertext, 0, -self::CRYPTO_AEAD_AES256GCM_ABYTES);
        /** @var string $authTag */
        $authTag = ParagonIE_Sodium_Core_Util::substr($ciphertext, -self::CRYPTO_AEAD_AES256GCM_ABYTES, 16);
        return openssl_decrypt(
            $ctext,
            &#039;aes-256-gcm&#039;,
            $key,
            OPENSSL_RAW_DATA,
            $nonce,
            $authTag,
            $assocData
        );
    }

    /**
     * Authenticated Encryption with Associated Data: Encryption
     *
     * Algorithm:
     *     AES-256-GCM
     *
     * @param string $plaintext Message to be encrypted
     * @param string $assocData Authenticated Associated Data (unencrypted)
     * @param string $nonce     Number to be used only Once; must be 8 bytes
     * @param string $key       Encryption key
     *
     * @return string           Ciphertext with a 16-byte GCM message
     *                          authentication code appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_aes256gcm_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        if (!self::crypto_aead_aes256gcm_is_available()) {
            throw new SodiumException(&#039;AES-256-GCM is not available&#039;);
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long&#039;);
        }

        if (!extension_loaded(&#039;openssl&#039;)) {
            throw new SodiumException(&#039;The OpenSSL extension is not installed&#039;);
        }
        if (!is_callable(&#039;openssl_encrypt&#039;)) {
            throw new SodiumException(&#039;The OpenSSL extension is not installed, or openssl_encrypt() is not available&#039;);
        }

        $authTag = &#039;&#039;;
        $ciphertext = openssl_encrypt(
            $plaintext,
            &#039;aes-256-gcm&#039;,
            $key,
            OPENSSL_RAW_DATA,
            $nonce,
            $authTag,
            $assocData
        );
        return $ciphertext . $authTag;
    }

    /**
     * Return a secure random key for use with the AES-256-GCM
     * symmetric AEAD interface.
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_aes256gcm_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AES256GCM_KEYBYTES);
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     ChaCha20-Poly1305
     *
     * This mode uses a 64-bit random nonce with a 64-bit counter.
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     *
     * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
     * @param string $assocData  Authenticated Associated Data (unencrypted)
     * @param string $nonce      Number to be used only Once; must be 8 bytes
     * @param string $key        Encryption key
     *
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_chacha20poly1305_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_ABYTES long&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_aead_chacha20poly1305_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback(&#039;crypto_aead_chacha20poly1305_decrypt&#039;)) {
            return call_user_func(
                &#039;\\Sodium\\crypto_aead_chacha20poly1305_decrypt&#039;,
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_decrypt(
            $ciphertext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Authenticated Encryption with Associated Data
     *
     * Algorithm:
     *     ChaCha20-Poly1305
     *
     * This mode uses a 64-bit random nonce with a 64-bit counter.
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     *
     * @param string $plaintext Message to be encrypted
     * @param string $assocData Authenticated Associated Data (unencrypted)
     * @param string $nonce     Number to be used only Once; must be 8 bytes
     * @param string $key       Encryption key
     *
     * @return string           Ciphertext with a 16-byte Poly1305 message
     *                          authentication code appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_chacha20poly1305_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES long&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_aead_chacha20poly1305_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback(&#039;crypto_aead_chacha20poly1305_encrypt&#039;)) {
            return (string) call_user_func(
                &#039;\\Sodium\\crypto_aead_chacha20poly1305_encrypt&#039;,
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_encrypt(
            $plaintext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     ChaCha20-Poly1305
     *
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     * Regular mode uses a 64-bit random nonce with a 64-bit counter.
     *
     * @param string $ciphertext Encrypted message (with Poly1305 MAC appended)
     * @param string $assocData  Authenticated Associated Data (unencrypted)
     * @param string $nonce      Number to be used only Once; must be 12 bytes
     * @param string $key        Encryption key
     *
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_aead_chacha20poly1305_ietf_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES long&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_aead_chacha20poly1305_ietf_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback(&#039;crypto_aead_chacha20poly1305_ietf_decrypt&#039;)) {
            return call_user_func(
                &#039;\\Sodium\\crypto_aead_chacha20poly1305_ietf_decrypt&#039;,
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_ietf_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_ietf_decrypt(
            $ciphertext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Return a secure random key for use with the ChaCha20-Poly1305
     * symmetric AEAD interface.
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_chacha20poly1305_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES);
    }

    /**
     * Authenticated Encryption with Associated Data
     *
     * Algorithm:
     *     ChaCha20-Poly1305
     *
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     * Regular mode uses a 64-bit random nonce with a 64-bit counter.
     *
     * @param string $plaintext Message to be encrypted
     * @param string $assocData Authenticated Associated Data (unencrypted)
     * @param string $nonce Number to be used only Once; must be 8 bytes
     * @param string $key Encryption key
     *
     * @return string           Ciphertext with a 16-byte Poly1305 message
     *                          authentication code appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_chacha20poly1305_ietf_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_aead_chacha20poly1305_ietf_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback(&#039;crypto_aead_chacha20poly1305_ietf_encrypt&#039;)) {
            return (string) call_user_func(
                &#039;\\Sodium\\crypto_aead_chacha20poly1305_ietf_encrypt&#039;,
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_chacha20poly1305_ietf_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_chacha20poly1305_ietf_encrypt(
            $plaintext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Return a secure random key for use with the ChaCha20-Poly1305
     * symmetric AEAD interface. (IETF version)
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_chacha20poly1305_ietf_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES);
    }

    /**
     * Authenticated Encryption with Associated Data: Decryption
     *
     * Algorithm:
     *     XChaCha20-Poly1305
     *
     * This mode uses a 64-bit random nonce with a 64-bit counter.
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     *
     * @param string $ciphertext   Encrypted message (with Poly1305 MAC appended)
     * @param string $assocData    Authenticated Associated Data (unencrypted)
     * @param string $nonce        Number to be used only Once; must be 8 bytes
     * @param string $key          Encryption key
     * @param bool   $dontFallback Don&#039;t fallback to ext/sodium
     *
     * @return string|bool         The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_xchacha20poly1305_ietf_decrypt(
        $ciphertext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        } else {
            $assocData = &#039;&#039;;
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES) {
            throw new SodiumException(&#039;Message must be at least CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES long&#039;);
        }
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            if (is_callable(&#039;sodium_crypto_aead_xchacha20poly1305_ietf_decrypt&#039;)) {
                return sodium_crypto_aead_xchacha20poly1305_ietf_decrypt(
                    $ciphertext,
                    $assocData,
                    $nonce,
                    $key
                );
            }
        }

        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_xchacha20poly1305_ietf_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_xchacha20poly1305_ietf_decrypt(
            $ciphertext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Authenticated Encryption with Associated Data
     *
     * Algorithm:
     *     XChaCha20-Poly1305
     *
     * This mode uses a 64-bit random nonce with a 64-bit counter.
     * IETF mode uses a 96-bit random nonce with a 32-bit counter.
     *
     * @param string $plaintext    Message to be encrypted
     * @param string $assocData    Authenticated Associated Data (unencrypted)
     * @param string $nonce        Number to be used only Once; must be 8 bytes
     * @param string $key          Encryption key
     * @param bool   $dontFallback Don&#039;t fallback to ext/sodium
     *
     * @return string           Ciphertext with a 16-byte Poly1305 message
     *                          authentication code appended
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_aead_xchacha20poly1305_ietf_encrypt(
        #[\SensitiveParameter]
        $plaintext = &#039;&#039;,
        $assocData = &#039;&#039;,
        $nonce = &#039;&#039;,
        #[\SensitiveParameter]
        $key = &#039;&#039;,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, &#039;string&#039;, 2);
        } else {
            $assocData = &#039;&#039;;
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException(&#039;Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_NPUBBYTES long&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
            throw new SodiumException(&#039;Key must be CRYPTO_AEAD_XCHACHA20POLY1305_KEYBYTES long&#039;);
        }
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            if (is_callable(&#039;sodium_crypto_aead_xchacha20poly1305_ietf_encrypt&#039;)) {
                return sodium_crypto_aead_xchacha20poly1305_ietf_encrypt(
                    $plaintext,
                    $assocData,
                    $nonce,
                    $key
                );
            }
        }

        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::aead_xchacha20poly1305_ietf_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        return ParagonIE_Sodium_Crypto::aead_xchacha20poly1305_ietf_encrypt(
            $plaintext,
            $assocData,
            $nonce,
            $key
        );
    }

    /**
     * Return a secure random key for use with the XChaCha20-Poly1305
     * symmetric AEAD interface.
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_aead_xchacha20poly1305_ietf_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES);
    }

    /**
     * Authenticate a message. Uses symmetric-key cryptography.
     *
     * Algorithm:
     *     HMAC-SHA512-256. Which is HMAC-SHA-512 truncated to 256 bits.
     *     Not to be confused with HMAC-SHA-512/256 which would use the
     *     SHA-512/256 hash function (uses different initial parameters
     *     but still truncates to 256 bits to sidestep length-extension
     *     attacks).
     *
     * @param string $message Message to be authenticated
     * @param string $key Symmetric authentication key
     * @return string         Message authentication code
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_auth(
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_AUTH_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_auth($message, $key);
        }
        if (self::use_fallback(&#039;crypto_auth&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_auth&#039;, $message, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::auth($message, $key);
        }
        return ParagonIE_Sodium_Crypto::auth($message, $key);
    }

    /**
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_auth_keygen()
    {
        return random_bytes(self::CRYPTO_AUTH_KEYBYTES);
    }

    /**
     * Verify the MAC of a message previously authenticated with crypto_auth.
     *
     * @param string $mac Message authentication code
     * @param string $message Message whose authenticity you are attempting to
     *                        verify (with a given MAC and key)
     * @param string $key Symmetric authentication key
     * @return bool           TRUE if authenticated, FALSE otherwise
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_auth_verify(
        $mac,
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($mac, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($mac) !== self::CRYPTO_AUTH_BYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_AUTH_BYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_AUTH_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_auth_verify($mac, $message, $key);
        }
        if (self::use_fallback(&#039;crypto_auth_verify&#039;)) {
            return (bool) call_user_func(&#039;\\Sodium\\crypto_auth_verify&#039;, $mac, $message, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::auth_verify($mac, $message, $key);
        }
        return ParagonIE_Sodium_Crypto::auth_verify($mac, $message, $key);
    }

    /**
     * Authenticated asymmetric-key encryption. Both the sender and recipient
     * may decrypt messages.
     *
     * Algorithm: X25519-XSalsa20-Poly1305.
     *     X25519: Elliptic-Curve Diffie Hellman over Curve25519.
     *     XSalsa20: Extended-nonce variant of salsa20.
     *     Poyl1305: Polynomial MAC for one-time message authentication.
     *
     * @param string $plaintext The message to be encrypted
     * @param string $nonce A Number to only be used Once; must be 24 bytes
     * @param string $keypair Your secret key and your recipient&#039;s public key
     * @return string           Ciphertext with 16-byte Poly1305 MAC
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box(
        $plaintext,
        $nonce,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box($plaintext, $nonce, $keypair);
        }
        if (self::use_fallback(&#039;crypto_box&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box&#039;, $plaintext, $nonce, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box($plaintext, $nonce, $keypair);
        }
        return ParagonIE_Sodium_Crypto::box($plaintext, $nonce, $keypair);
    }

    /**
     * Anonymous public-key encryption. Only the recipient may decrypt messages.
     *
     * Algorithm: X25519-XSalsa20-Poly1305, as with crypto_box.
     *     The sender&#039;s X25519 keypair is ephemeral.
     *     Nonce is generated from the BLAKE2b hash of both public keys.
     *
     * This provides ciphertext integrity.
     *
     * @param string $plaintext Message to be sealed
     * @param string $publicKey Your recipient&#039;s public key
     * @return string           Sealed message that only your recipient can
     *                          decrypt
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_seal(
        #[\SensitiveParameter]
        $plaintext,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_seal($plaintext, $publicKey);
        }
        if (self::use_fallback(&#039;crypto_box_seal&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_seal&#039;, $plaintext, $publicKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_seal($plaintext, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::box_seal($plaintext, $publicKey);
    }

    /**
     * Opens a message encrypted with crypto_box_seal(). Requires
     * the recipient&#039;s keypair (sk || pk) to decrypt successfully.
     *
     * This validates ciphertext integrity.
     *
     * @param string $ciphertext Sealed message to be opened
     * @param string $keypair    Your crypto_box keypair
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_box_seal_open(
        $ciphertext,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_box_seal_open($ciphertext, $keypair);
        }
        if (self::use_fallback(&#039;crypto_box_seal_open&#039;)) {
            return call_user_func(&#039;\\Sodium\\crypto_box_seal_open&#039;, $ciphertext, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_seal_open($ciphertext, $keypair);
        }
        return ParagonIE_Sodium_Crypto::box_seal_open($ciphertext, $keypair);
    }

    /**
     * Generate a new random X25519 keypair.
     *
     * @return string A 64-byte string; the first 32 are your secret key, while
     *                the last 32 are your public key. crypto_box_secretkey()
     *                and crypto_box_publickey() exist to separate them so you
     *                don&#039;t accidentally get them mixed up!
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_keypair()
    {
        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_keypair();
        }
        if (self::use_fallback(&#039;crypto_box_keypair&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_keypair&#039;);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_keypair();
        }
        return ParagonIE_Sodium_Crypto::box_keypair();
    }

    /**
     * Combine two keys into a keypair for use in library methods that expect
     * a keypair. This doesn&#039;t necessarily have to be the same person&#039;s keys.
     *
     * @param string $secretKey Secret key
     * @param string $publicKey Public key
     * @return string    Keypair
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_keypair_from_secretkey_and_publickey(
        #[\SensitiveParameter]
        $secretKey,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
        }
        if (self::use_fallback(&#039;crypto_box_keypair_from_secretkey_and_publickey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_keypair_from_secretkey_and_publickey&#039;, $secretKey, $publicKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
    }

    /**
     * Decrypt a message previously encrypted with crypto_box().
     *
     * @param string $ciphertext Encrypted message
     * @param string $nonce      Number to only be used Once; must be 24 bytes
     * @param string $keypair    Your secret key and the sender&#039;s public key
     * @return string            The original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_box_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_BOX_MACBYTES) {
            throw new SodiumException(&#039;Argument 1 must be at least CRYPTO_BOX_MACBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_box_open($ciphertext, $nonce, $keypair);
        }
        if (self::use_fallback(&#039;crypto_box_open&#039;)) {
            return call_user_func(&#039;\\Sodium\\crypto_box_open&#039;, $ciphertext, $nonce, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_open($ciphertext, $nonce, $keypair);
        }
        return ParagonIE_Sodium_Crypto::box_open($ciphertext, $nonce, $keypair);
    }

    /**
     * Extract the public key from a crypto_box keypair.
     *
     * @param string $keypair Keypair containing secret and public key
     * @return string         Your crypto_box public key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_publickey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_publickey($keypair);
        }
        if (self::use_fallback(&#039;crypto_box_publickey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_publickey&#039;, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_publickey($keypair);
        }
        return ParagonIE_Sodium_Crypto::box_publickey($keypair);
    }

    /**
     * Calculate the X25519 public key from a given X25519 secret key.
     *
     * @param string $secretKey Any X25519 secret key
     * @return string           The corresponding X25519 public key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_publickey_from_secretkey(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_publickey_from_secretkey($secretKey);
        }
        if (self::use_fallback(&#039;crypto_box_publickey_from_secretkey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_publickey_from_secretkey&#039;, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_publickey_from_secretkey($secretKey);
        }
        return ParagonIE_Sodium_Crypto::box_publickey_from_secretkey($secretKey);
    }

    /**
     * Extract the secret key from a crypto_box keypair.
     *
     * @param string $keypair
     * @return string         Your crypto_box secret key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_box_secretkey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_secretkey($keypair);
        }
        if (self::use_fallback(&#039;crypto_box_secretkey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_secretkey&#039;, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_secretkey($keypair);
        }
        return ParagonIE_Sodium_Crypto::box_secretkey($keypair);
    }

    /**
     * Generate an X25519 keypair from a seed.
     *
     * @param string $seed
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress UndefinedFunction
     */
    public static function crypto_box_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, &#039;string&#039;, 1);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_seed_keypair($seed);
        }
        if (self::use_fallback(&#039;crypto_box_seed_keypair&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_box_seed_keypair&#039;, $seed);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_seed_keypair($seed);
        }
        return ParagonIE_Sodium_Crypto::box_seed_keypair($seed);
    }

    /**
     * Calculates a BLAKE2b hash, with an optional key.
     *
     * @param string      $message The message to be hashed
     * @param string|null $key     If specified, must be a string between 16
     *                             and 64 bytes long
     * @param int         $length  Output length in bytes; must be between 16
     *                             and 64 (default = 32)
     * @return string              Raw binary
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_generichash(
        $message,
        #[\SensitiveParameter]
        $key = &#039;&#039;,
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        if (is_null($key)) {
            $key = &#039;&#039;;
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, &#039;int&#039;, 3);

        /* Input validation: */
        if (!empty($key)) {
            if (ParagonIE_Sodium_Core_Util::strlen($key) &lt; self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException(&#039;Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.&#039;);
            }
            if (ParagonIE_Sodium_Core_Util::strlen($key) &gt; self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException(&#039;Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.&#039;);
            }
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_generichash($message, $key, $length);
        }
        if (self::use_fallback(&#039;crypto_generichash&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_generichash&#039;, $message, $key, $length);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash($message, $key, $length);
        }
        return ParagonIE_Sodium_Crypto::generichash($message, $key, $length);
    }

    /**
     * Get the final BLAKE2b hash output for a given context.
     *
     * @param string $ctx BLAKE2 hashing context. Generated by crypto_generichash_init().
     * @param int $length Hash output size.
     * @return string     Final BLAKE2b hash.
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress ReferenceConstraintViolation
     * @psalm-suppress ConflictingReferenceConstraint
     */
    public static function crypto_generichash_final(
        #[\SensitiveParameter]
        &amp;$ctx,
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ctx, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, &#039;int&#039;, 2);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_generichash_final($ctx, $length);
        }
        if (self::use_fallback(&#039;crypto_generichash_final&#039;)) {
            $func = &#039;\\Sodium\\crypto_generichash_final&#039;;
            return (string) $func($ctx, $length);
        }
        if ($length &lt; 1) {
            try {
                self::memzero($ctx);
            } catch (SodiumException $ex) {
                unset($ctx);
            }
            return &#039;&#039;;
        }
        if (PHP_INT_SIZE === 4) {
            $result = ParagonIE_Sodium_Crypto32::generichash_final($ctx, $length);
        } else {
            $result = ParagonIE_Sodium_Crypto::generichash_final($ctx, $length);
        }
        try {
            self::memzero($ctx);
        } catch (SodiumException $ex) {
            unset($ctx);
        }
        return $result;
    }

    /**
     * Initialize a BLAKE2b hashing context, for use in a streaming interface.
     *
     * @param string|null $key If specified must be a string between 16 and 64 bytes
     * @param int $length      The size of the desired hash output
     * @return string          A BLAKE2 hashing context, encoded as a string
     *                         (To be 100% compatible with ext/libsodium)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_generichash_init(
        #[\SensitiveParameter]
        $key = &#039;&#039;,
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        if (is_null($key)) {
            $key = &#039;&#039;;
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, &#039;int&#039;, 2);

        /* Input validation: */
        if (!empty($key)) {
            if (ParagonIE_Sodium_Core_Util::strlen($key) &lt; self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException(&#039;Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.&#039;);
            }
            if (ParagonIE_Sodium_Core_Util::strlen($key) &gt; self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException(&#039;Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.&#039;);
            }
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_generichash_init($key, $length);
        }
        if (self::use_fallback(&#039;crypto_generichash_init&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_generichash_init&#039;, $key, $length);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash_init($key, $length);
        }
        return ParagonIE_Sodium_Crypto::generichash_init($key, $length);
    }

    /**
     * Initialize a BLAKE2b hashing context, for use in a streaming interface.
     *
     * @param string|null $key If specified must be a string between 16 and 64 bytes
     * @param int $length      The size of the desired hash output
     * @param string $salt     Salt (up to 16 bytes)
     * @param string $personal Personalization string (up to 16 bytes)
     * @return string          A BLAKE2 hashing context, encoded as a string
     *                         (To be 100% compatible with ext/libsodium)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_generichash_init_salt_personal(
        #[\SensitiveParameter]
        $key = &#039;&#039;,
        $length = self::CRYPTO_GENERICHASH_BYTES,
        $salt = &#039;&#039;,
        $personal = &#039;&#039;
    ) {
        /* Type checks: */
        if (is_null($key)) {
            $key = &#039;&#039;;
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, &#039;int&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($personal, &#039;string&#039;, 4);
        $salt = str_pad($salt, 16, &quot;\0&quot;, STR_PAD_RIGHT);
        $personal = str_pad($personal, 16, &quot;\0&quot;, STR_PAD_RIGHT);

        /* Input validation: */
        if (!empty($key)) {
            /*
            if (ParagonIE_Sodium_Core_Util::strlen($key) &lt; self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException(&#039;Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.&#039;);
            }
            */
            if (ParagonIE_Sodium_Core_Util::strlen($key) &gt; self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException(&#039;Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.&#039;);
            }
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash_init_salt_personal($key, $length, $salt, $personal);
        }
        return ParagonIE_Sodium_Crypto::generichash_init_salt_personal($key, $length, $salt, $personal);
    }

    /**
     * Update a BLAKE2b hashing context with additional data.
     *
     * @param string $ctx    BLAKE2 hashing context. Generated by crypto_generichash_init().
     *                       $ctx is passed by reference and gets updated in-place.
     * @param-out string $ctx
     * @param string $message The message to append to the existing hash state.
     * @return void
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress ReferenceConstraintViolation
     */
    public static function crypto_generichash_update(
        #[\SensitiveParameter]
        &amp;$ctx,
        $message
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ctx, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            sodium_crypto_generichash_update($ctx, $message);
            return;
        }
        if (self::use_fallback(&#039;crypto_generichash_update&#039;)) {
            $func = &#039;\\Sodium\\crypto_generichash_update&#039;;
            $func($ctx, $message);
            return;
        }
        if (PHP_INT_SIZE === 4) {
            $ctx = ParagonIE_Sodium_Crypto32::generichash_update($ctx, $message);
        } else {
            $ctx = ParagonIE_Sodium_Crypto::generichash_update($ctx, $message);
        }
    }

    /**
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_generichash_keygen()
    {
        return random_bytes(self::CRYPTO_GENERICHASH_KEYBYTES);
    }

    /**
     * @param int $subkey_len
     * @param int $subkey_id
     * @param string $context
     * @param string $key
     * @return string
     * @throws SodiumException
     */
    public static function crypto_kdf_derive_from_key(
        $subkey_len,
        $subkey_id,
        $context,
        #[\SensitiveParameter]
        $key
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($subkey_len, &#039;int&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($subkey_id, &#039;int&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($context, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);
        $subkey_id = (int) $subkey_id;
        $subkey_len = (int) $subkey_len;
        $context = (string) $context;
        $key = (string) $key;

        if ($subkey_len &lt; self::CRYPTO_KDF_BYTES_MIN) {
            throw new SodiumException(&#039;subkey cannot be smaller than SODIUM_CRYPTO_KDF_BYTES_MIN&#039;);
        }
        if ($subkey_len &gt; self::CRYPTO_KDF_BYTES_MAX) {
            throw new SodiumException(&#039;subkey cannot be larger than SODIUM_CRYPTO_KDF_BYTES_MAX&#039;);
        }
        if ($subkey_id &lt; 0) {
            throw new SodiumException(&#039;subkey_id cannot be negative&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($context) !== self::CRYPTO_KDF_CONTEXTBYTES) {
            throw new SodiumException(&#039;context should be SODIUM_CRYPTO_KDF_CONTEXTBYTES bytes&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_KDF_KEYBYTES) {
            throw new SodiumException(&#039;key should be SODIUM_CRYPTO_KDF_KEYBYTES bytes&#039;);
        }

        $salt = ParagonIE_Sodium_Core_Util::store64_le($subkey_id);
        $state = self::crypto_generichash_init_salt_personal(
            $key,
            $subkey_len,
            $salt,
            $context
        );
        return self::crypto_generichash_final($state, $subkey_len);
    }

    /**
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_kdf_keygen()
    {
        return random_bytes(self::CRYPTO_KDF_KEYBYTES);
    }

    /**
     * Perform a key exchange, between a designated client and a server.
     *
     * Typically, you would designate one machine to be the client and the
     * other to be the server. The first two keys are what you&#039;d expect for
     * scalarmult() below, but the latter two public keys don&#039;t swap places.
     *
     * | ALICE                          | BOB                                 |
     * | Client                         | Server                              |
     * |--------------------------------|-------------------------------------|
     * | shared = crypto_kx(            | shared = crypto_kx(                 |
     * |     alice_sk,                  |     bob_sk,                         | &lt;- contextual
     * |     bob_pk,                    |     alice_pk,                       | &lt;- contextual
     * |     alice_pk,                  |     alice_pk,                       | &lt;----- static
     * |     bob_pk                     |     bob_pk                          | &lt;----- static
     * | )                              | )                                   |
     *
     * They are used along with the scalarmult product to generate a 256-bit
     * BLAKE2b hash unique to the client and server keys.
     *
     * @param string $my_secret
     * @param string $their_public
     * @param string $client_public
     * @param string $server_public
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_kx(
        #[\SensitiveParameter]
        $my_secret,
        $their_public,
        $client_public,
        $server_public,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($my_secret, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($their_public, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($client_public, &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($server_public, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($my_secret) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($their_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($client_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($server_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 4 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            if (is_callable(&#039;sodium_crypto_kx&#039;)) {
                return (string) sodium_crypto_kx(
                    $my_secret,
                    $their_public,
                    $client_public,
                    $server_public
                );
            }
        }
        if (self::use_fallback(&#039;crypto_kx&#039;)) {
            return (string) call_user_func(
                &#039;\\Sodium\\crypto_kx&#039;,
                $my_secret,
                $their_public,
                $client_public,
                $server_public
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::keyExchange(
                $my_secret,
                $their_public,
                $client_public,
                $server_public
            );
        }
        return ParagonIE_Sodium_Crypto::keyExchange(
            $my_secret,
            $their_public,
            $client_public,
            $server_public
        );
    }

    /**
     * @param string $seed
     * @return string
     * @throws SodiumException
     */
    public static function crypto_kx_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, &#039;string&#039;, 1);

        $seed = (string) $seed;

        if (ParagonIE_Sodium_Core_Util::strlen($seed) !== self::CRYPTO_KX_SEEDBYTES) {
            throw new SodiumException(&#039;seed must be SODIUM_CRYPTO_KX_SEEDBYTES bytes&#039;);
        }

        $sk = self::crypto_generichash($seed, &#039;&#039;, self::CRYPTO_KX_SECRETKEYBYTES);
        $pk = self::crypto_scalarmult_base($sk);
        return $sk . $pk;
    }

    /**
     * @return string
     * @throws Exception
     */
    public static function crypto_kx_keypair()
    {
        $sk = self::randombytes_buf(self::CRYPTO_KX_SECRETKEYBYTES);
        $pk = self::crypto_scalarmult_base($sk);
        return $sk . $pk;
    }

    /**
     * @param string $keypair
     * @param string $serverPublicKey
     * @return array{0: string, 1: string}
     * @throws SodiumException
     */
    public static function crypto_kx_client_session_keys(
        #[\SensitiveParameter]
        $keypair,
        $serverPublicKey
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($serverPublicKey, &#039;string&#039;, 2);

        $keypair = (string) $keypair;
        $serverPublicKey = (string) $serverPublicKey;

        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($serverPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes&#039;);
        }

        $sk = self::crypto_kx_secretkey($keypair);
        $pk = self::crypto_kx_publickey($keypair);
        $h = self::crypto_generichash_init(null, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
        self::crypto_generichash_update($h, self::crypto_scalarmult($sk, $serverPublicKey));
        self::crypto_generichash_update($h, $pk);
        self::crypto_generichash_update($h, $serverPublicKey);
        $sessionKeys = self::crypto_generichash_final($h, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
        return array(
            ParagonIE_Sodium_Core_Util::substr(
                $sessionKeys,
                0,
                self::CRYPTO_KX_SESSIONKEYBYTES
            ),
            ParagonIE_Sodium_Core_Util::substr(
                $sessionKeys,
                self::CRYPTO_KX_SESSIONKEYBYTES,
                self::CRYPTO_KX_SESSIONKEYBYTES
            )
        );
    }

    /**
     * @param string $keypair
     * @param string $clientPublicKey
     * @return array{0: string, 1: string}
     * @throws SodiumException
     */
    public static function crypto_kx_server_session_keys(
        #[\SensitiveParameter]
        $keypair,
        $clientPublicKey
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($clientPublicKey, &#039;string&#039;, 2);

        $keypair = (string) $keypair;
        $clientPublicKey = (string) $clientPublicKey;

        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
            throw new SodiumException(&#039;keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($clientPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes&#039;);
        }

        $sk = self::crypto_kx_secretkey($keypair);
        $pk = self::crypto_kx_publickey($keypair);
        $h = self::crypto_generichash_init(null, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
        self::crypto_generichash_update($h, self::crypto_scalarmult($sk, $clientPublicKey));
        self::crypto_generichash_update($h, $clientPublicKey);
        self::crypto_generichash_update($h, $pk);
        $sessionKeys = self::crypto_generichash_final($h, self::CRYPTO_KX_SESSIONKEYBYTES * 2);
        return array(
            ParagonIE_Sodium_Core_Util::substr(
                $sessionKeys,
                self::CRYPTO_KX_SESSIONKEYBYTES,
                self::CRYPTO_KX_SESSIONKEYBYTES
            ),
            ParagonIE_Sodium_Core_Util::substr(
                $sessionKeys,
                0,
                self::CRYPTO_KX_SESSIONKEYBYTES
            )
        );
    }

    /**
     * @param string $kp
     * @return string
     * @throws SodiumException
     */
    public static function crypto_kx_secretkey(
        #[\SensitiveParameter]
        $kp
    ) {
        return ParagonIE_Sodium_Core_Util::substr(
            $kp,
            0,
            self::CRYPTO_KX_SECRETKEYBYTES
        );
    }

    /**
     * @param string $kp
     * @return string
     * @throws SodiumException
     */
    public static function crypto_kx_publickey($kp)
    {
        return ParagonIE_Sodium_Core_Util::substr(
            $kp,
            self::CRYPTO_KX_SECRETKEYBYTES,
            self::CRYPTO_KX_PUBLICKEYBYTES
        );
    }

    /**
     * @param int $outlen
     * @param string $passwd
     * @param string $salt
     * @param int $opslimit
     * @param int $memlimit
     * @param int|null $alg
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_pwhash(
        $outlen,
        #[\SensitiveParameter]
        $passwd,
        $salt,
        $opslimit,
        $memlimit,
        $alg = null
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($outlen, &#039;int&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt,  &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, &#039;int&#039;, 4);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, &#039;int&#039;, 5);

        if (self::useNewSodiumAPI()) {
            if (!is_null($alg)) {
                ParagonIE_Sodium_Core_Util::declareScalarType($alg, &#039;int&#039;, 6);
                return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit, $alg);
            }
            return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit);
        }
        if (self::use_fallback(&#039;crypto_pwhash&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_pwhash&#039;, $outlen, $passwd, $salt, $opslimit, $memlimit);
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * !Exclusive to sodium_compat!
     *
     * This returns TRUE if the native crypto_pwhash API is available by libsodium.
     * This returns FALSE if only sodium_compat is available.
     *
     * @return bool
     */
    public static function crypto_pwhash_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return true;
        }
        if (self::use_fallback(&#039;crypto_pwhash&#039;)) {
            return true;
        }
        return false;
    }

    /**
     * @param string $passwd
     * @param int $opslimit
     * @param int $memlimit
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_pwhash_str(
        #[\SensitiveParameter]
        $passwd,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, &#039;int&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, &#039;int&#039;, 3);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_pwhash_str($passwd, $opslimit, $memlimit);
        }
        if (self::use_fallback(&#039;crypto_pwhash_str&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_pwhash_str&#039;, $passwd, $opslimit, $memlimit);
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * Do we need to rehash this password?
     *
     * @param string $hash
     * @param int $opslimit
     * @param int $memlimit
     * @return bool
     * @throws SodiumException
     */
    public static function crypto_pwhash_str_needs_rehash(
        #[\SensitiveParameter]
        $hash,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, &#039;int&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, &#039;int&#039;, 3);

        // Just grab the first 4 pieces.
        $pieces = explode(&#039;$&#039;, (string) $hash);
        $prefix = implode(&#039;$&#039;, array_slice($pieces, 0, 4));

        // Rebuild the expected header.
        /** @var int $ops */
        $ops = (int) $opslimit;
        /** @var int $mem */
        $mem = (int) $memlimit &gt;&gt; 10;
        $encoded = self::CRYPTO_PWHASH_STRPREFIX . &#039;v=19$m=&#039; . $mem . &#039;,t=&#039; . $ops . &#039;,p=1&#039;;

        // Do they match? If so, we don&#039;t need to rehash, so return false.
        return !ParagonIE_Sodium_Core_Util::hashEquals($encoded, $prefix);
    }

    /**
     * @param string $passwd
     * @param string $hash
     * @return bool
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_pwhash_str_verify(
        #[\SensitiveParameter]
        $passwd,
        #[\SensitiveParameter]
        $hash
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_pwhash_str_verify($passwd, $hash);
        }
        if (self::use_fallback(&#039;crypto_pwhash_str_verify&#039;)) {
            return (bool) call_user_func(&#039;\\Sodium\\crypto_pwhash_str_verify&#039;, $passwd, $hash);
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * @param int $outlen
     * @param string $passwd
     * @param string $salt
     * @param int $opslimit
     * @param int $memlimit
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function crypto_pwhash_scryptsalsa208sha256(
        $outlen,
        #[\SensitiveParameter]
        $passwd,
        $salt,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($outlen, &#039;int&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt,  &#039;string&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, &#039;int&#039;, 4);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, &#039;int&#039;, 5);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_pwhash_scryptsalsa208sha256(
                (int) $outlen,
                (string) $passwd,
                (string) $salt,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        if (self::use_fallback(&#039;crypto_pwhash_scryptsalsa208sha256&#039;)) {
            return (string) call_user_func(
                &#039;\\Sodium\\crypto_pwhash_scryptsalsa208sha256&#039;,
                (int) $outlen,
                (string) $passwd,
                (string) $salt,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * !Exclusive to sodium_compat!
     *
     * This returns TRUE if the native crypto_pwhash API is available by libsodium.
     * This returns FALSE if only sodium_compat is available.
     *
     * @return bool
     */
    public static function crypto_pwhash_scryptsalsa208sha256_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return true;
        }
        if (self::use_fallback(&#039;crypto_pwhash_scryptsalsa208sha256&#039;)) {
            return true;
        }
        return false;
    }

    /**
     * @param string $passwd
     * @param int $opslimit
     * @param int $memlimit
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function crypto_pwhash_scryptsalsa208sha256_str(
        #[\SensitiveParameter]
        $passwd,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, &#039;int&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, &#039;int&#039;, 3);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_pwhash_scryptsalsa208sha256_str(
                (string) $passwd,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        if (self::use_fallback(&#039;crypto_pwhash_scryptsalsa208sha256_str&#039;)) {
            return (string) call_user_func(
                &#039;\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str&#039;,
                (string) $passwd,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * @param string $passwd
     * @param string $hash
     * @return bool
     * @throws SodiumException
     * @throws TypeError
     */
    public static function crypto_pwhash_scryptsalsa208sha256_str_verify(
        #[\SensitiveParameter]
        $passwd,
        #[\SensitiveParameter]
        $hash
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_pwhash_scryptsalsa208sha256_str_verify(
                (string) $passwd,
                (string) $hash
            );
        }
        if (self::use_fallback(&#039;crypto_pwhash_scryptsalsa208sha256_str_verify&#039;)) {
            return (bool) call_user_func(
                &#039;\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str_verify&#039;,
                (string) $passwd,
                (string) $hash
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP&#039;
        );
    }

    /**
     * Calculate the shared secret between your secret key and your
     * recipient&#039;s public key.
     *
     * Algorithm: X25519 (ECDH over Curve25519)
     *
     * @param string $secretKey
     * @param string $publicKey
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_scalarmult(
        #[\SensitiveParameter]
        $secretKey,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_scalarmult($secretKey, $publicKey);
        }
        if (self::use_fallback(&#039;crypto_scalarmult&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_scalarmult&#039;, $secretKey, $publicKey);
        }

        /* Output validation: Forbid all-zero keys */
        if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat(&quot;\0&quot;, self::CRYPTO_BOX_SECRETKEYBYTES))) {
            throw new SodiumException(&#039;Zero secret key is not allowed&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::hashEquals($publicKey, str_repeat(&quot;\0&quot;, self::CRYPTO_BOX_PUBLICKEYBYTES))) {
            throw new SodiumException(&#039;Zero public key is not allowed&#039;);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::scalarmult($secretKey, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::scalarmult($secretKey, $publicKey);
    }

    /**
     * Calculate an X25519 public key from an X25519 secret key.
     *
     * @param string $secretKey
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress TooFewArguments
     * @psalm-suppress MixedArgument
     */
    public static function crypto_scalarmult_base(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_scalarmult_base($secretKey);
        }
        if (self::use_fallback(&#039;crypto_scalarmult_base&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_scalarmult_base&#039;, $secretKey);
        }
        if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat(&quot;\0&quot;, self::CRYPTO_BOX_SECRETKEYBYTES))) {
            throw new SodiumException(&#039;Zero secret key is not allowed&#039;);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::scalarmult_base($secretKey);
        }
        return ParagonIE_Sodium_Crypto::scalarmult_base($secretKey);
    }

    /**
     * Authenticated symmetric-key encryption.
     *
     * Algorithm: XSalsa20-Poly1305
     *
     * @param string $plaintext The message you&#039;re encrypting
     * @param string $nonce A Number to be used Once; must be 24 bytes
     * @param string $key Symmetric encryption key
     * @return string           Ciphertext with Poly1305 MAC
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_secretbox(
        #[\SensitiveParameter]
        $plaintext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_secretbox($plaintext, $nonce, $key);
        }
        if (self::use_fallback(&#039;crypto_secretbox&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_secretbox&#039;, $plaintext, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox($plaintext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox($plaintext, $nonce, $key);
    }

    /**
     * Decrypts a message previously encrypted with crypto_secretbox().
     *
     * @param string $ciphertext Ciphertext with Poly1305 MAC
     * @param string $nonce      A Number to be used Once; must be 24 bytes
     * @param string $key        Symmetric encryption key
     * @return string            Original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_secretbox_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
        }
        if (self::use_fallback(&#039;crypto_secretbox_open&#039;)) {
            return call_user_func(&#039;\\Sodium\\crypto_secretbox_open&#039;, $ciphertext, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox_open($ciphertext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox_open($ciphertext, $nonce, $key);
    }

    /**
     * Return a secure random key for use with crypto_secretbox
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_secretbox_keygen()
    {
        return random_bytes(self::CRYPTO_SECRETBOX_KEYBYTES);
    }

    /**
     * Authenticated symmetric-key encryption.
     *
     * Algorithm: XChaCha20-Poly1305
     *
     * @param string $plaintext The message you&#039;re encrypting
     * @param string $nonce     A Number to be used Once; must be 24 bytes
     * @param string $key       Symmetric encryption key
     * @return string           Ciphertext with Poly1305 MAC
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_secretbox_xchacha20poly1305($plaintext, $nonce, $key)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.&#039;);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
    }
    /**
     * Decrypts a message previously encrypted with crypto_secretbox_xchacha20poly1305().
     *
     * @param string $ciphertext Ciphertext with Poly1305 MAC
     * @param string $nonce      A Number to be used Once; must be 24 bytes
     * @param string $key        Symmetric encryption key
     * @return string            Original plaintext message
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_secretbox_xchacha20poly1305_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) &lt; self::CRYPTO_SECRETBOX_MACBYTES) {
            throw new SodiumException(&quot;Ciphertext must be at least CRYPTO_SECRETBOX_MACBYTES long&quot;);
        }

        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox_xchacha20poly1305_open($ciphertext, $nonce, $key);
    }

    /**
     * @param string $key
     * @return array&lt;int, string&gt; Returns a state and a header.
     * @throws Exception
     * @throws SodiumException
     */
    public static function crypto_secretstream_xchacha20poly1305_init_push(
        #[\SensitiveParameter]
        $key
    ) {
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_init_push($key);
        }
        return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_init_push($key);
    }

    /**
     * @param string $header
     * @param string $key
     * @return string Returns a state.
     * @throws Exception
     */
    public static function crypto_secretstream_xchacha20poly1305_init_pull(
        $header,
        #[\SensitiveParameter]
        $key
    ) {
        if (ParagonIE_Sodium_Core_Util::strlen($header) &lt; self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES) {
            throw new SodiumException(
                &#039;header size should be SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES bytes&#039;
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_init_pull($key, $header);
        }
        return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_init_pull($key, $header);
    }

    /**
     * @param string $state
     * @param string $msg
     * @param string $aad
     * @param int $tag
     * @return string
     * @throws SodiumException
     */
    public static function crypto_secretstream_xchacha20poly1305_push(
        #[\SensitiveParameter]
        &amp;$state,
        #[\SensitiveParameter]
        $msg,
        $aad = &#039;&#039;,
        $tag = 0
    ) {
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_push(
                $state,
                $msg,
                $aad,
                $tag
            );
        }
        return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_push(
            $state,
            $msg,
            $aad,
            $tag
        );
    }

    /**
     * @param string $state
     * @param string $msg
     * @param string $aad
     * @return bool|array{0: string, 1: int}
     * @throws SodiumException
     */
    public static function crypto_secretstream_xchacha20poly1305_pull(
        #[\SensitiveParameter]
        &amp;$state,
        $msg,
        $aad = &#039;&#039;
    ) {
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_pull(
                $state,
                $msg,
                $aad
            );
        }
        return ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_pull(
            $state,
            $msg,
            $aad
        );
    }

    /**
     * @return string
     * @throws Exception
     */
    public static function crypto_secretstream_xchacha20poly1305_keygen()
    {
        return random_bytes(self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES);
    }

    /**
     * @param string $state
     * @return void
     * @throws SodiumException
     */
    public static function crypto_secretstream_xchacha20poly1305_rekey(
        #[\SensitiveParameter]
        &amp;$state
    ) {
        if (PHP_INT_SIZE === 4) {
            ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_rekey($state);
        } else {
            ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_rekey($state);
        }
    }

    /**
     * Calculates a SipHash-2-4 hash of a message for a given key.
     *
     * @param string $message Input message
     * @param string $key SipHash-2-4 key
     * @return string         Hash
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_shorthash(
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SHORTHASH_KEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SHORTHASH_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_shorthash($message, $key);
        }
        if (self::use_fallback(&#039;crypto_shorthash&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_shorthash&#039;, $message, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_SipHash::sipHash24($message, $key);
        }
        return ParagonIE_Sodium_Core_SipHash::sipHash24($message, $key);
    }

    /**
     * Return a secure random key for use with crypto_shorthash
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_shorthash_keygen()
    {
        return random_bytes(self::CRYPTO_SHORTHASH_KEYBYTES);
    }

    /**
     * Returns a signed message. You probably want crypto_sign_detached()
     * instead, which only returns the signature.
     *
     * Algorithm: Ed25519 (EdDSA over Curve25519)
     *
     * @param string $message Message to be signed.
     * @param string $secretKey Secret signing key.
     * @return string           Signed message (signature is prefixed).
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_sign(
        $message,
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign($message, $secretKey);
        }
        if (self::use_fallback(&#039;crypto_sign&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign&#039;, $message, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign($message, $secretKey);
        }
        return ParagonIE_Sodium_Crypto::sign($message, $secretKey);
    }

    /**
     * Validates a signed message then returns the message.
     *
     * @param string $signedMessage A signed message
     * @param string $publicKey A public key
     * @return string               The original message (if the signature is
     *                              valid for this public key)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress MixedReturnStatement
     */
    public static function crypto_sign_open(
        $signedMessage,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($signedMessage, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($signedMessage) &lt; self::CRYPTO_SIGN_BYTES) {
            throw new SodiumException(&#039;Argument 1 must be at least CRYPTO_SIGN_BYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SIGN_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            /**
             * @psalm-suppress InvalidReturnStatement
             * @psalm-suppress FalsableReturnStatement
             */
            return sodium_crypto_sign_open($signedMessage, $publicKey);
        }
        if (self::use_fallback(&#039;crypto_sign_open&#039;)) {
            return call_user_func(&#039;\\Sodium\\crypto_sign_open&#039;, $signedMessage, $publicKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign_open($signedMessage, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::sign_open($signedMessage, $publicKey);
    }

    /**
     * Generate a new random Ed25519 keypair.
     *
     * @return string
     * @throws SodiumException
     * @throws TypeError
     */
    public static function crypto_sign_keypair()
    {
        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_keypair();
        }
        if (self::use_fallback(&#039;crypto_sign_keypair&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_keypair&#039;);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::keypair();
        }
        return ParagonIE_Sodium_Core_Ed25519::keypair();
    }

    /**
     * @param string $sk
     * @param string $pk
     * @return string
     * @throws SodiumException
     */
    public static function crypto_sign_keypair_from_secretkey_and_publickey(
        #[\SensitiveParameter]
        $sk,
        $pk
    )  {
        ParagonIE_Sodium_Core_Util::declareScalarType($sk, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($pk, &#039;string&#039;, 1);
        $sk = (string) $sk;
        $pk = (string) $pk;

        if (ParagonIE_Sodium_Core_Util::strlen($sk) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException(&#039;secretkey should be SODIUM_CRYPTO_SIGN_SECRETKEYBYTES bytes&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($pk) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;publickey should be SODIUM_CRYPTO_SIGN_PUBLICKEYBYTES bytes&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_keypair_from_secretkey_and_publickey($sk, $pk);
        }
        return $sk . $pk;
    }

    /**
     * Generate an Ed25519 keypair from a seed.
     *
     * @param string $seed Input seed
     * @return string      Keypair
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, &#039;string&#039;, 1);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_seed_keypair($seed);
        }
        if (self::use_fallback(&#039;crypto_sign_keypair&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_seed_keypair&#039;, $seed);
        }
        $publicKey = &#039;&#039;;
        $secretKey = &#039;&#039;;
        if (PHP_INT_SIZE === 4) {
            ParagonIE_Sodium_Core32_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        } else {
            ParagonIE_Sodium_Core_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        }
        return $secretKey . $publicKey;
    }

    /**
     * Extract an Ed25519 public key from an Ed25519 keypair.
     *
     * @param string $keypair Keypair
     * @return string         Public key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_publickey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_publickey($keypair);
        }
        if (self::use_fallback(&#039;crypto_sign_publickey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_publickey&#039;, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::publickey($keypair);
        }
        return ParagonIE_Sodium_Core_Ed25519::publickey($keypair);
    }

    /**
     * Calculate an Ed25519 public key from an Ed25519 secret key.
     *
     * @param string $secretKey Your Ed25519 secret key
     * @return string           The corresponding Ed25519 public key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_publickey_from_secretkey(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_SIGN_SECRETKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_publickey_from_secretkey($secretKey);
        }
        if (self::use_fallback(&#039;crypto_sign_publickey_from_secretkey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_publickey_from_secretkey&#039;, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::publickey_from_secretkey($secretKey);
        }
        return ParagonIE_Sodium_Core_Ed25519::publickey_from_secretkey($secretKey);
    }

    /**
     * Extract an Ed25519 secret key from an Ed25519 keypair.
     *
     * @param string $keypair Keypair
     * @return string         Secret key
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_secretkey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_secretkey($keypair);
        }
        if (self::use_fallback(&#039;crypto_sign_secretkey&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_secretkey&#039;, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::secretkey($keypair);
        }
        return ParagonIE_Sodium_Core_Ed25519::secretkey($keypair);
    }

    /**
     * Calculate the Ed25519 signature of a message and return ONLY the signature.
     *
     * Algorithm: Ed25519 (EdDSA over Curve25519)
     *
     * @param string $message Message to be signed
     * @param string $secretKey Secret signing key
     * @return string           Digital signature
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_detached(
        $message,
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, &#039;string&#039;, 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_detached($message, $secretKey);
        }
        if (self::use_fallback(&#039;crypto_sign_detached&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_detached&#039;, $message, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign_detached($message, $secretKey);
        }
        return ParagonIE_Sodium_Crypto::sign_detached($message, $secretKey);
    }

    /**
     * Verify the Ed25519 signature of a message.
     *
     * @param string $signature Digital sginature
     * @param string $message Message to be verified
     * @param string $publicKey Public key
     * @return bool             TRUE if this signature is good for this public key;
     *                          FALSE otherwise
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_verify_detached($signature, $message, $publicKey)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($signature, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($signature) !== self::CRYPTO_SIGN_BYTES) {
            throw new SodiumException(&#039;Argument 1 must be CRYPTO_SIGN_BYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SIGN_PUBLICKEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_verify_detached($signature, $message, $publicKey);
        }
        if (self::use_fallback(&#039;crypto_sign_verify_detached&#039;)) {
            return (bool) call_user_func(
                &#039;\\Sodium\\crypto_sign_verify_detached&#039;,
                $signature,
                $message,
                $publicKey
            );
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign_verify_detached($signature, $message, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::sign_verify_detached($signature, $message, $publicKey);
    }

    /**
     * Convert an Ed25519 public key to a Curve25519 public key
     *
     * @param string $pk
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_ed25519_pk_to_curve25519($pk)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($pk, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($pk) &lt; self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException(&#039;Argument 1 must be at least CRYPTO_SIGN_PUBLICKEYBYTES long.&#039;);
        }
        if (self::useNewSodiumAPI()) {
            if (is_callable(&#039;crypto_sign_ed25519_pk_to_curve25519&#039;)) {
                return (string) sodium_crypto_sign_ed25519_pk_to_curve25519($pk);
            }
        }
        if (self::use_fallback(&#039;crypto_sign_ed25519_pk_to_curve25519&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_ed25519_pk_to_curve25519&#039;, $pk);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::pk_to_curve25519($pk);
        }
        return ParagonIE_Sodium_Core_Ed25519::pk_to_curve25519($pk);
    }

    /**
     * Convert an Ed25519 secret key to a Curve25519 secret key
     *
     * @param string $sk
     * @return string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_sign_ed25519_sk_to_curve25519(
        #[\SensitiveParameter]
        $sk
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($sk, &#039;string&#039;, 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($sk) &lt; self::CRYPTO_SIGN_SEEDBYTES) {
            throw new SodiumException(&#039;Argument 1 must be at least CRYPTO_SIGN_SEEDBYTES long.&#039;);
        }
        if (self::useNewSodiumAPI()) {
            if (is_callable(&#039;crypto_sign_ed25519_sk_to_curve25519&#039;)) {
                return sodium_crypto_sign_ed25519_sk_to_curve25519($sk);
            }
        }
        if (self::use_fallback(&#039;crypto_sign_ed25519_sk_to_curve25519&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_sign_ed25519_sk_to_curve25519&#039;, $sk);
        }

        $h = hash(&#039;sha512&#039;, ParagonIE_Sodium_Core_Util::substr($sk, 0, 32), true);
        $h[0] = ParagonIE_Sodium_Core_Util::intToChr(
            ParagonIE_Sodium_Core_Util::chrToInt($h[0]) &amp; 248
        );
        $h[31] = ParagonIE_Sodium_Core_Util::intToChr(
            (ParagonIE_Sodium_Core_Util::chrToInt($h[31]) &amp; 127) | 64
        );
        return ParagonIE_Sodium_Core_Util::substr($h, 0, 32);
    }

    /**
     * Expand a key and nonce into a keystream of pseudorandom bytes.
     *
     * @param int $len Number of bytes desired
     * @param string $nonce Number to be used Once; must be 24 bytes
     * @param string $key XSalsa20 key
     * @return string       Pseudorandom stream that can be XORed with messages
     *                      to provide encryption (but not authentication; see
     *                      Poly1305 or crypto_auth() for that, which is not
     *                      optional for security)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_stream(
        $len,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($len, &#039;int&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_STREAM_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_stream($len, $nonce, $key);
        }
        if (self::use_fallback(&#039;crypto_stream&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_stream&#039;, $len, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_XSalsa20::xsalsa20($len, $nonce, $key);
        }
        return ParagonIE_Sodium_Core_XSalsa20::xsalsa20($len, $nonce, $key);
    }

    /**
     * DANGER! UNAUTHENTICATED ENCRYPTION!
     *
     * Unless you are following expert advice, do not use this feature.
     *
     * Algorithm: XSalsa20
     *
     * This DOES NOT provide ciphertext integrity.
     *
     * @param string $message Plaintext message
     * @param string $nonce Number to be used Once; must be 24 bytes
     * @param string $key Encryption key
     * @return string         Encrypted text which is vulnerable to chosen-
     *                        ciphertext attacks unless you implement some
     *                        other mitigation to the ciphertext (i.e.
     *                        Encrypt then MAC)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_stream_xor(
        #[\SensitiveParameter]
        $message,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_stream_xor($message, $nonce, $key);
        }
        if (self::use_fallback(&#039;crypto_stream_xor&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\crypto_stream_xor&#039;, $message, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_XSalsa20::xsalsa20_xor($message, $nonce, $key);
        }
        return ParagonIE_Sodium_Core_XSalsa20::xsalsa20_xor($message, $nonce, $key);
    }

    /**
     * Return a secure random key for use with crypto_stream
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_stream_keygen()
    {
        return random_bytes(self::CRYPTO_STREAM_KEYBYTES);
    }


    /**
     * Expand a key and nonce into a keystream of pseudorandom bytes.
     *
     * @param int $len Number of bytes desired
     * @param string $nonce Number to be used Once; must be 24 bytes
     * @param string $key XChaCha20 key
     * @param bool $dontFallback
     * @return string       Pseudorandom stream that can be XORed with messages
     *                      to provide encryption (but not authentication; see
     *                      Poly1305 or crypto_auth() for that, which is not
     *                      optional for security)
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_stream_xchacha20(
        $len,
        $nonce,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($len, &#039;int&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_STREAM_XCHACHA20_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_stream_xchacha20($len, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_XChaCha20::stream($len, $nonce, $key);
        }
        return ParagonIE_Sodium_Core_XChaCha20::stream($len, $nonce, $key);
    }

    /**
     * DANGER! UNAUTHENTICATED ENCRYPTION!
     *
     * Unless you are following expert advice, do not use this feature.
     *
     * Algorithm: XChaCha20
     *
     * This DOES NOT provide ciphertext integrity.
     *
     * @param string $message Plaintext message
     * @param string $nonce Number to be used Once; must be 24 bytes
     * @param string $key Encryption key
     * @return string         Encrypted text which is vulnerable to chosen-
     *                        ciphertext attacks unless you implement some
     *                        other mitigation to the ciphertext (i.e.
     *                        Encrypt then MAC)
     * @param bool $dontFallback
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_stream_xchacha20_xor(
        #[\SensitiveParameter]
        $message,
        $nonce,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_XCHACHA20_KEYBYTES long.&#039;);
        }

        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_stream_xchacha20_xor($message, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_XChaCha20::streamXorIc($message, $nonce, $key);
        }
        return ParagonIE_Sodium_Core_XChaCha20::streamXorIc($message, $nonce, $key);
    }

    /**
     * DANGER! UNAUTHENTICATED ENCRYPTION!
     *
     * Unless you are following expert advice, do not use this feature.
     *
     * Algorithm: XChaCha20
     *
     * This DOES NOT provide ciphertext integrity.
     *
     * @param string $message Plaintext message
     * @param string $nonce Number to be used Once; must be 24 bytes
     * @param int $counter
     * @param string $key Encryption key
     * @return string         Encrypted text which is vulnerable to chosen-
     *                        ciphertext attacks unless you implement some
     *                        other mitigation to the ciphertext (i.e.
     *                        Encrypt then MAC)
     * @param bool $dontFallback
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function crypto_stream_xchacha20_xor_ic(
        #[\SensitiveParameter]
        $message,
        $nonce,
        $counter,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, &#039;string&#039;, 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($counter, &#039;int&#039;, 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, &#039;string&#039;, 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException(&#039;Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.&#039;);
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException(&#039;Argument 3 must be CRYPTO_SECRETBOX_XCHACHA20_KEYBYTES long.&#039;);
        }

        if (is_callable(&#039;sodium_crypto_stream_xchacha20_xor_ic&#039;) &amp;&amp; !$dontFallback) {
            return sodium_crypto_stream_xchacha20_xor_ic($message, $nonce, $counter, $key);
        }

        $ic = ParagonIE_Sodium_Core_Util::store64_le($counter);
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_XChaCha20::streamXorIc($message, $nonce, $key, $ic);
        }
        return ParagonIE_Sodium_Core_XChaCha20::streamXorIc($message, $nonce, $key, $ic);
    }

    /**
     * Return a secure random key for use with crypto_stream_xchacha20
     *
     * @return string
     * @throws Exception
     * @throws Error
     */
    public static function crypto_stream_xchacha20_keygen()
    {
        return random_bytes(self::CRYPTO_STREAM_XCHACHA20_KEYBYTES);
    }

    /**
     * Cache-timing-safe implementation of hex2bin().
     *
     * @param string $string Hexadecimal string
     * @param string $ignore List of characters to ignore; useful for whitespace
     * @return string        Raw binary string
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress TooFewArguments
     * @psalm-suppress MixedArgument
     */
    public static function hex2bin(
        #[\SensitiveParameter]
        $string,
        $ignore = &#039;&#039;
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($string, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($ignore, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            if (is_callable(&#039;sodium_hex2bin&#039;)) {
                return (string) sodium_hex2bin($string, $ignore);
            }
        }
        if (self::use_fallback(&#039;hex2bin&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\hex2bin&#039;, $string, $ignore);
        }
        return ParagonIE_Sodium_Core_Util::hex2bin($string, $ignore);
    }

    /**
     * Increase a string (little endian)
     *
     * @param string $var
     *
     * @return void
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function increment(
        #[\SensitiveParameter]
        &amp;$var
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($var, &#039;string&#039;, 1);

        if (self::useNewSodiumAPI()) {
            sodium_increment($var);
            return;
        }
        if (self::use_fallback(&#039;increment&#039;)) {
            $func = &#039;\\Sodium\\increment&#039;;
            $func($var);
            return;
        }

        $len = ParagonIE_Sodium_Core_Util::strlen($var);
        if ($len &lt; 1) {
            throw new SodiumException(&#039;Argument 1 cannot be empty&#039;);
        }
        $c = 1;
        $copy = &#039;&#039;;
        for ($i = 0; $i &lt; $len; ++$i) {
            $c += ParagonIE_Sodium_Core_Util::chrToInt(
                ParagonIE_Sodium_Core_Util::substr($var, $i, 1)
            );
            $copy .= ParagonIE_Sodium_Core_Util::intToChr($c);
            $c &gt;&gt;= 8;
        }
        $var = $copy;
    }

    /**
     * @param string $str
     * @return bool
     *
     * @throws SodiumException
     */
    public static function is_zero(
        #[\SensitiveParameter]
        $str
    ) {
        $d = 0;
        for ($i = 0; $i &lt; 32; ++$i) {
            $d |= ParagonIE_Sodium_Core_Util::chrToInt($str[$i]);
        }
        return ((($d - 1) &gt;&gt; 31) &amp; 1) === 1;
    }

    /**
     * The equivalent to the libsodium minor version we aim to be compatible
     * with (sans pwhash and memzero).
     *
     * @return int
     */
    public static function library_version_major()
    {
        if (self::useNewSodiumAPI() &amp;&amp; defined(&#039;SODIUM_LIBRARY_MAJOR_VERSION&#039;)) {
            return SODIUM_LIBRARY_MAJOR_VERSION;
        }
        if (self::use_fallback(&#039;library_version_major&#039;)) {
            /** @psalm-suppress UndefinedFunction */
            return (int) call_user_func(&#039;\\Sodium\\library_version_major&#039;);
        }
        return self::LIBRARY_VERSION_MAJOR;
    }

    /**
     * The equivalent to the libsodium minor version we aim to be compatible
     * with (sans pwhash and memzero).
     *
     * @return int
     */
    public static function library_version_minor()
    {
        if (self::useNewSodiumAPI() &amp;&amp; defined(&#039;SODIUM_LIBRARY_MINOR_VERSION&#039;)) {
            return SODIUM_LIBRARY_MINOR_VERSION;
        }
        if (self::use_fallback(&#039;library_version_minor&#039;)) {
            /** @psalm-suppress UndefinedFunction */
            return (int) call_user_func(&#039;\\Sodium\\library_version_minor&#039;);
        }
        return self::LIBRARY_VERSION_MINOR;
    }

    /**
     * Compare two strings.
     *
     * @param string $left
     * @param string $right
     * @return int
     * @throws SodiumException
     * @throws TypeError
     * @psalm-suppress MixedArgument
     */
    public static function memcmp(
        #[\SensitiveParameter]
        $left,
        #[\SensitiveParameter]
        $right
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($left, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($right, &#039;string&#039;, 2);

        if (self::useNewSodiumAPI()) {
            return sodium_memcmp($left, $right);
        }
        if (self::use_fallback(&#039;memcmp&#039;)) {
            return (int) call_user_func(&#039;\\Sodium\\memcmp&#039;, $left, $right);
        }
        /** @var string $left */
        /** @var string $right */
        return ParagonIE_Sodium_Core_Util::memcmp($left, $right);
    }

    /**
     * It&#039;s actually not possible to zero memory buffers in PHP. You need the
     * native library for that.
     *
     * @param string|null $var
     * @param-out string|null $var
     *
     * @return void
     * @throws SodiumException (Unless libsodium is installed)
     * @throws TypeError
     * @psalm-suppress TooFewArguments
     */
    public static function memzero(
        #[\SensitiveParameter]
        &amp;$var
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($var, &#039;string&#039;, 1);

        if (self::useNewSodiumAPI()) {
            /** @psalm-suppress MixedArgument */
            sodium_memzero($var);
            return;
        }
        if (self::use_fallback(&#039;memzero&#039;)) {
            $func = &#039;\\Sodium\\memzero&#039;;
            $func($var);
            if ($var === null) {
                return;
            }
        }
        // This is the best we can do.
        throw new SodiumException(
            &#039;This is not implemented in sodium_compat, as it is not possible to securely wipe memory from PHP. &#039; .
            &#039;To fix this error, make sure libsodium is installed and the PHP extension is enabled.&#039;
        );
    }

    /**
     * @param string $unpadded
     * @param int $blockSize
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function pad(
        #[\SensitiveParameter]
        $unpadded,
        $blockSize,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($unpadded, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, &#039;int&#039;, 2);

        $unpadded = (string) $unpadded;
        $blockSize = (int) $blockSize;

        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return (string) sodium_pad($unpadded, $blockSize);
        }

        if ($blockSize &lt;= 0) {
            throw new SodiumException(
                &#039;block size cannot be less than 1&#039;
            );
        }
        $unpadded_len = ParagonIE_Sodium_Core_Util::strlen($unpadded);
        $xpadlen = ($blockSize - 1);
        if (($blockSize &amp; ($blockSize - 1)) === 0) {
            $xpadlen -= $unpadded_len &amp; ($blockSize - 1);
        } else {
            $xpadlen -= $unpadded_len % $blockSize;
        }

        $xpadded_len = $unpadded_len + $xpadlen;
        $padded = str_repeat(&quot;\0&quot;, $xpadded_len - 1);
        if ($unpadded_len &gt; 0) {
            $st = 1;
            $i = 0;
            $k = $unpadded_len;
            for ($j = 0; $j &lt;= $xpadded_len; ++$j) {
                $i = (int) $i;
                $k = (int) $k;
                $st = (int) $st;
                if ($j &gt;= $unpadded_len) {
                    $padded[$j] = &quot;\0&quot;;
                } else {
                    $padded[$j] = $unpadded[$j];
                }
                /** @var int $k */
                $k -= $st;
                $st = (int) (~(
                            (
                                (
                                    ($k &gt;&gt; 48)
                                        |
                                    ($k &gt;&gt; 32)
                                        |
                                    ($k &gt;&gt; 16)
                                        |
                                    $k
                                ) - 1
                            ) &gt;&gt; 16
                        )
                    ) &amp; 1;
                $i += $st;
            }
        }

        $mask = 0;
        $tail = $xpadded_len;
        for ($i = 0; $i &lt; $blockSize; ++$i) {
            # barrier_mask = (unsigned char)
            #     (((i ^ xpadlen) - 1U) &gt;&gt; ((sizeof(size_t) - 1U) * CHAR_BIT));
            $barrier_mask = (($i ^ $xpadlen) -1) &gt;&gt; ((PHP_INT_SIZE &lt;&lt; 3) - 1);
            # tail[-i] = (tail[-i] &amp; mask) | (0x80 &amp; barrier_mask);
            $padded[$tail - $i] = ParagonIE_Sodium_Core_Util::intToChr(
                (ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]) &amp; $mask)
                    |
                (0x80 &amp; $barrier_mask)
            );
            # mask |= barrier_mask;
            $mask |= $barrier_mask;
        }
        return $padded;
    }

    /**
     * @param string $padded
     * @param int $blockSize
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function unpad(
        #[\SensitiveParameter]
        $padded,
        $blockSize,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($padded, &#039;string&#039;, 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, &#039;int&#039;, 2);

        $padded = (string) $padded;
        $blockSize = (int) $blockSize;

        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return (string) sodium_unpad($padded, $blockSize);
        }
        if ($blockSize &lt;= 0) {
            throw new SodiumException(&#039;block size cannot be less than 1&#039;);
        }
        $padded_len = ParagonIE_Sodium_Core_Util::strlen($padded);
        if ($padded_len &lt; $blockSize) {
            throw new SodiumException(&#039;invalid padding&#039;);
        }

        # tail = &amp;padded[padded_len - 1U];
        $tail = $padded_len - 1;

        $acc = 0;
        $valid = 0;
        $pad_len = 0;

        $found = 0;
        for ($i = 0; $i &lt; $blockSize; ++$i) {
            # c = tail[-i];
            $c = ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]);

            # is_barrier =
            #     (( (acc - 1U) &amp; (pad_len - 1U) &amp; ((c ^ 0x80) - 1U) ) &gt;&gt; 8) &amp; 1U;
            $is_barrier = (
                (
                    ($acc - 1) &amp; ($pad_len - 1) &amp; (($c ^ 80) - 1)
                ) &gt;&gt; 7
            ) &amp; 1;
            $is_barrier &amp;= ~$found;
            $found |= $is_barrier;

            # acc |= c;
            $acc |= $c;

            # pad_len |= i &amp; (1U + ~is_barrier);
            $pad_len |= $i &amp; (1 + ~$is_barrier);

            # valid |= (unsigned char) is_barrier;
            $valid |= ($is_barrier &amp; 0xff);
        }
        # unpadded_len = padded_len - 1U - pad_len;
        $unpadded_len = $padded_len - 1 - $pad_len;
        if ($valid !== 1) {
            throw new SodiumException(&#039;invalid padding&#039;);
        }
        return ParagonIE_Sodium_Core_Util::substr($padded, 0, $unpadded_len);
    }

    /**
     * Will sodium_compat run fast on the current hardware and PHP configuration?
     *
     * @return bool
     */
    public static function polyfill_is_fast()
    {
        if (extension_loaded(&#039;sodium&#039;)) {
            return true;
        }
        if (extension_loaded(&#039;libsodium&#039;)) {
            return true;
        }
        return PHP_INT_SIZE === 8;
    }

    /**
     * Generate a string of bytes from the kernel&#039;s CSPRNG.
     * Proudly uses /dev/urandom (if getrandom(2) is not available).
     *
     * @param int $numBytes
     * @return string
     * @throws Exception
     * @throws TypeError
     */
    public static function randombytes_buf($numBytes)
    {
        /* Type checks: */
        if (!is_int($numBytes)) {
            if (is_numeric($numBytes)) {
                $numBytes = (int) $numBytes;
            } else {
                throw new TypeError(
                    &#039;Argument 1 must be an integer, &#039; . gettype($numBytes) . &#039; given.&#039;
                );
            }
        }
        /** @var positive-int $numBytes */
        if (self::use_fallback(&#039;randombytes_buf&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\randombytes_buf&#039;, $numBytes);
        }
        if ($numBytes &lt; 0) {
            throw new SodiumException(&quot;Number of bytes must be a positive integer&quot;);
        }
        return random_bytes($numBytes);
    }

    /**
     * Generate an integer between 0 and $range (non-inclusive).
     *
     * @param int $range
     * @return int
     * @throws Exception
     * @throws Error
     * @throws TypeError
     */
    public static function randombytes_uniform($range)
    {
        /* Type checks: */
        if (!is_int($range)) {
            if (is_numeric($range)) {
                $range = (int) $range;
            } else {
                throw new TypeError(
                    &#039;Argument 1 must be an integer, &#039; . gettype($range) . &#039; given.&#039;
                );
            }
        }
        if (self::use_fallback(&#039;randombytes_uniform&#039;)) {
            return (int) call_user_func(&#039;\\Sodium\\randombytes_uniform&#039;, $range);
        }
        return random_int(0, $range - 1);
    }

    /**
     * Generate a random 16-bit integer.
     *
     * @return int
     * @throws Exception
     * @throws Error
     * @throws TypeError
     */
    public static function randombytes_random16()
    {
        if (self::use_fallback(&#039;randombytes_random16&#039;)) {
            return (int) call_user_func(&#039;\\Sodium\\randombytes_random16&#039;);
        }
        return random_int(0, 65535);
    }

    /**
     * @param string $p
     * @param bool $dontFallback
     * @return bool
     * @throws SodiumException
     */
    public static function ristretto255_is_valid_point(
        #[\SensitiveParameter]
        $p,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_is_valid_point($p);
        }
        try {
            $r = ParagonIE_Sodium_Core_Ristretto255::ristretto255_frombytes($p);
            return $r[&#039;res&#039;] === 0 &amp;&amp;
                ParagonIE_Sodium_Core_Ristretto255::ristretto255_point_is_canonical($p) === 1;
        } catch (SodiumException $ex) {
            if ($ex-&gt;getMessage() === &#039;S is not canonical&#039;) {
                return false;
            }
            throw $ex;
        }
    }

    /**
     * @param string $p
     * @param string $q
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_add(
        #[\SensitiveParameter]
        $p,
        #[\SensitiveParameter]
        $q,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_add($p, $q);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_add($p, $q);
    }

    /**
     * @param string $p
     * @param string $q
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_sub(
        #[\SensitiveParameter]
        $p,
        #[\SensitiveParameter]
        $q,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_sub($p, $q);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_sub($p, $q);
    }

    /**
     * @param string $r
     * @param bool $dontFallback
     * @return string
     *
     * @throws SodiumException
     */
    public static function ristretto255_from_hash(
        #[\SensitiveParameter]
        $r,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_from_hash($r);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_from_hash($r);
    }

    /**
     * @param bool $dontFallback
     * @return string
     *
     * @throws SodiumException
     */
    public static function ristretto255_random($dontFallback = false)
    {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_random();
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_random();
    }

    /**
     * @param bool $dontFallback
     * @return string
     *
     * @throws SodiumException
     */
    public static function ristretto255_scalar_random($dontFallback = false)
    {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_random();
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_random();
    }

    /**
     * @param string $s
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_invert(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_invert($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_invert($s);
    }
    /**
     * @param string $s
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_negate(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_negate($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_negate($s);
    }

    /**
     * @param string $s
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_complement(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_complement($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_complement($s);
    }

    /**
     * @param string $x
     * @param string $y
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_add(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_add($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_add($x, $y);
    }

    /**
     * @param string $x
     * @param string $y
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_sub(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_sub($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_sub($x, $y);
    }

    /**
     * @param string $x
     * @param string $y
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_mul(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_mul($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_mul($x, $y);
    }

    /**
     * @param string $n
     * @param string $p
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function scalarmult_ristretto255(
        #[\SensitiveParameter]
        $n,
        #[\SensitiveParameter]
        $p,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_scalarmult_ristretto255($n, $p);
        }
        return ParagonIE_Sodium_Core_Ristretto255::scalarmult_ristretto255($n, $p);
    }

    /**
     * @param string $n
     * @param string $p
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function scalarmult_ristretto255_base(
        #[\SensitiveParameter]
        $n,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_scalarmult_ristretto255_base($n);
        }
        return ParagonIE_Sodium_Core_Ristretto255::scalarmult_ristretto255_base($n);
    }

    /**
     * @param string $s
     * @param bool $dontFallback
     * @return string
     * @throws SodiumException
     */
    public static function ristretto255_scalar_reduce(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() &amp;&amp; !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_reduce($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::sc_reduce($s);
    }

    /**
     * Runtime testing method for 32-bit platforms.
     *
     * Usage: If runtime_speed_test() returns FALSE, then our 32-bit
     *        implementation is to slow to use safely without risking timeouts.
     *        If this happens, install sodium from PECL to get acceptable
     *        performance.
     *
     * @param int $iterations Number of multiplications to attempt
     * @param int $maxTimeout Milliseconds
     * @return bool           TRUE if we&#039;re fast enough, FALSE is not
     * @throws SodiumException
     */
    public static function runtime_speed_test($iterations, $maxTimeout)
    {
        if (self::polyfill_is_fast()) {
            return true;
        }
        /** @var float $end */
        $end = 0.0;
        /** @var float $start */
        $start = microtime(true);
        /** @var ParagonIE_Sodium_Core32_Int64 $a */
        $a = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 &lt;&lt; 16));
        for ($i = 0; $i &lt; $iterations; ++$i) {
            /** @var ParagonIE_Sodium_Core32_Int64 $b */
            $b = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 &lt;&lt; 16));
            $a-&gt;mulInt64($b);
        }
        /** @var float $end */
        $end = microtime(true);
        /** @var int $diff */
        $diff = (int) ceil(($end - $start) * 1000);
        return $diff &lt; $maxTimeout;
    }

    /**
     * Add two numbers (little-endian unsigned), storing the value in the first
     * parameter.
     *
     * This mutates $val.
     *
     * @param string $val
     * @param string $addv
     * @return void
     * @throws SodiumException
     */
    public static function sub(
        #[\SensitiveParameter]
        &amp;$val,
        #[\SensitiveParameter]
        $addv
    ) {
        $val_len = ParagonIE_Sodium_Core_Util::strlen($val);
        $addv_len = ParagonIE_Sodium_Core_Util::strlen($addv);
        if ($val_len !== $addv_len) {
            throw new SodiumException(&#039;values must have the same length&#039;);
        }
        $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);
        $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);

        $c = 0;
        for ($i = 0; $i &lt; $val_len; $i++) {
            $c = ($A[$i] - $B[$i] - $c);
            $A[$i] = ($c &amp; 0xff);
            $c = ($c &gt;&gt; 8) &amp; 1;
        }
        $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);
    }

    /**
     * This emulates libsodium&#039;s version_string() function, except ours is
     * prefixed with &#039;polyfill-&#039;.
     *
     * @return string
     * @psalm-suppress MixedInferredReturnType
     * @psalm-suppress UndefinedFunction
     */
    public static function version_string()
    {
        if (self::useNewSodiumAPI()) {
            return (string) sodium_version_string();
        }
        if (self::use_fallback(&#039;version_string&#039;)) {
            return (string) call_user_func(&#039;\\Sodium\\version_string&#039;);
        }
        return (string) self::VERSION_STRING;
    }

    /**
     * Should we use the libsodium core function instead?
     * This is always a good idea, if it&#039;s available. (Unless we&#039;re in the
     * middle of running our unit test suite.)
     *
     * If ext/libsodium is available, use it. Return TRUE.
     * Otherwise, we have to use the code provided herein. Return FALSE.
     *
     * @param string $sodium_func_name
     *
     * @return bool
     */
    protected static function use_fallback($sodium_func_name = &#039;&#039;)
    {
        static $res = null;
        if ($res === null) {
            $res = extension_loaded(&#039;libsodium&#039;) &amp;&amp; PHP_VERSION_ID &gt;= 50300;
        }
        if ($res === false) {
            // No libsodium installed
            return false;
        }
        if (self::$disableFallbackForUnitTests) {
            // Don&#039;t fallback. Use the PHP implementation.
            return false;
        }
        if (!empty($sodium_func_name)) {
            return is_callable(&#039;\\Sodium\\&#039; . $sodium_func_name);
        }
        return true;
    }

    /**
     * Libsodium as implemented in PHP 7.2
     * and/or ext/sodium (via PECL)
     *
     * @ref https://wiki.php.net/rfc/libsodium
     * @return bool
     */
    protected static function useNewSodiumAPI()
    {
        static $res = null;
        if ($res === null) {
            $res = PHP_VERSION_ID &gt;= 70000 &amp;&amp; extension_loaded(&#039;sodium&#039;);
        }
        if (self::$disableFallbackForUnitTests) {
            // Don&#039;t fallback. Use the PHP implementation.
            return false;
        }
        return (bool) $res;
    }
}
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