<?php



if (class_exists('ParagonIE_Sodium_Compat', false)) {
    return;
}

class ParagonIE_Sodium_Compat
{
    
    public static $disableFallbackForUnitTests = false;

    
    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 = 'polyfill-1.0.8';

    // 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 = 'x25519blake2b';
    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 = '$argon2id$';
    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 = '$7$';
    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;

    
    public static function add(
        #[\SensitiveParameter]
        &$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('values must have the same length');
        }
        $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);
        $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);

        $c = 0;
        for ($i = 0; $i < $val_len; $i++) {
            $c += ($A[$i] + $B[$i]);
            $A[$i] = ($c & 0xff);
            $c >>= 8;
        }
        $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);
    }

    
    public static function base642bin(
        #[\SensitiveParameter]
        $encoded,
        $variant,
        $ignore = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($encoded, 'string', 1);

        
        $encoded = (string) $encoded;
        if (ParagonIE_Sodium_Core_Util::strlen($encoded) === 0) {
            return '';
        }

        // Just strip before decoding
        if (!empty($ignore)) {
            $encoded = str_replace($ignore, '', $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::decode($encoded, false);
                case self::BASE64_VARIANT_URLSAFE:
                    return ParagonIE_Sodium_Core_Base64_UrlSafe::decode($encoded, true);
                case self::BASE64_VARIANT_URLSAFE_NO_PADDING:
                    return ParagonIE_Sodium_Core_Base64_UrlSafe::decode($encoded, false);
                default:
                    throw new SodiumException('invalid base64 variant identifier');
            }
        } catch (Exception $ex) {
            if ($ex instanceof SodiumException) {
                throw $ex;
            }
            throw new SodiumException('invalid base64 string');
        }
    }

    
    public static function bin2base64(
        #[\SensitiveParameter]
        $decoded,
        $variant
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($decoded, 'string', 1);
        
        $decoded = (string) $decoded;
        if (ParagonIE_Sodium_Core_Util::strlen($decoded) === 0) {
            return '';
        }

        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('invalid base64 variant identifier');
        }
    }

    
    public static function bin2hex(
        #[\SensitiveParameter]
        $string
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($string, 'string', 1);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_bin2hex($string);
        }
        if (self::use_fallback('bin2hex')) {
            return (string) call_user_func('\\Sodium\\bin2hex', $string);
        }
        return ParagonIE_Sodium_Core_Util::bin2hex($string);
    }

    
    public static function compare(
        #[\SensitiveParameter]
        $left,
        #[\SensitiveParameter]
        $right
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($left, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($right, 'string', 2);

        if (self::useNewSodiumAPI()) {
            return (int) sodium_compare($left, $right);
        }
        if (self::use_fallback('compare')) {
            return (int) call_user_func('\\Sodium\\compare', $left, $right);
        }
        return ParagonIE_Sodium_Core_Util::compare($left, $right);
    }

    
    public static function crypto_aead_aegis128l_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS128L_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AEGIS_128L_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS128L_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long');
        }
        $ct_length = ParagonIE_Sodium_Core_Util::strlen($ciphertext);
        if ($ct_length < self::CRYPTO_AEAD_AEGIS128L_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_AEGIS128L_ABYTES long');
        }

        $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);
    }

    
    public static function crypto_aead_aegis128l_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS128L_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS128L_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long');
        }

        list($ct, $tag) = ParagonIE_Sodium_Core_AEGIS128L::encrypt($plaintext, $assocData, $key, $nonce);
        return $ct . $tag;
    }

    
    public static function crypto_aead_aegis128l_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AEGIS128L_KEYBYTES);
    }

    
    public static function crypto_aead_aegis256_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS256_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AEGIS256_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS256_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AEGIS256_KEYBYTES long');
        }
        $ct_length = ParagonIE_Sodium_Core_Util::strlen($ciphertext);
        if ($ct_length < self::CRYPTO_AEAD_AEGIS256_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_AEGIS256_ABYTES long');
        }

        $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);
    }

    
    public static function crypto_aead_aegis256_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AEGIS256_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AEGIS256_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AEGIS128L_KEYBYTES long');
        }

        list($ct, $tag) = ParagonIE_Sodium_Core_AEGIS256::encrypt($plaintext, $assocData, $key, $nonce);
        return $ct . $tag;
    }

    
    public static function crypto_aead_aegis256_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AEGIS256_KEYBYTES);
    }

    
    public static function crypto_aead_aes256gcm_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return sodium_crypto_aead_aes256gcm_is_available();
        }
        if (self::use_fallback('crypto_aead_aes256gcm_is_available')) {
            return call_user_func('\\Sodium\\crypto_aead_aes256gcm_is_available');
        }
        if (PHP_VERSION_ID < 70100) {
            // OpenSSL doesn't support AEAD before 7.1.0
            return false;
        }
        if (!is_callable('openssl_encrypt') || !is_callable('openssl_decrypt')) {
            // OpenSSL isn't installed
            return false;
        }
        return (bool) in_array('aes-256-gcm', openssl_get_cipher_methods());
    }

    
    public static function crypto_aead_aes256gcm_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        if (!self::crypto_aead_aes256gcm_is_available()) {
            throw new SodiumException('AES-256-GCM is not available');
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_AES256GCM_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_AES256GCM_ABYTES long');
        }
        if (!is_callable('openssl_decrypt')) {
            throw new SodiumException('The OpenSSL extension is not installed, or openssl_decrypt() is not available');
        }

        
        $ctext = ParagonIE_Sodium_Core_Util::substr($ciphertext, 0, -self::CRYPTO_AEAD_AES256GCM_ABYTES);
        
        $authTag = ParagonIE_Sodium_Core_Util::substr($ciphertext, -self::CRYPTO_AEAD_AES256GCM_ABYTES, 16);
        return openssl_decrypt(
            $ctext,
            'aes-256-gcm',
            $key,
            OPENSSL_RAW_DATA,
            $nonce,
            $authTag,
            $assocData
        );
    }

    
    public static function crypto_aead_aes256gcm_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        if (!self::crypto_aead_aes256gcm_is_available()) {
            throw new SodiumException('AES-256-GCM is not available');
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_AES256GCM_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_AES256GCM_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_AES256GCM_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_AES256GCM_KEYBYTES long');
        }

        if (!is_callable('openssl_encrypt')) {
            throw new SodiumException('The OpenSSL extension is not installed, or openssl_encrypt() is not available');
        }

        $authTag = '';
        $ciphertext = openssl_encrypt(
            $plaintext,
            'aes-256-gcm',
            $key,
            OPENSSL_RAW_DATA,
            $nonce,
            $authTag,
            $assocData
        );
        return $ciphertext . $authTag;
    }

    
    public static function crypto_aead_aes256gcm_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_AES256GCM_KEYBYTES);
    }

    
    public static function crypto_aead_chacha20poly1305_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_ABYTES long');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_aead_chacha20poly1305_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback('crypto_aead_chacha20poly1305_decrypt')) {
            return call_user_func(
                '\\Sodium\\crypto_aead_chacha20poly1305_decrypt',
                $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
        );
    }

    
    public static function crypto_aead_chacha20poly1305_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_aead_chacha20poly1305_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback('crypto_aead_chacha20poly1305_encrypt')) {
            return (string) call_user_func(
                '\\Sodium\\crypto_aead_chacha20poly1305_encrypt',
                $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
        );
    }

    
    public static function crypto_aead_chacha20poly1305_ietf_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_CHACHA20POLY1305_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_CHACHA20POLY1305_ABYTES long');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_aead_chacha20poly1305_ietf_decrypt(
                $ciphertext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback('crypto_aead_chacha20poly1305_ietf_decrypt')) {
            return call_user_func(
                '\\Sodium\\crypto_aead_chacha20poly1305_ietf_decrypt',
                $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
        );
    }

    
    public static function crypto_aead_chacha20poly1305_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES);
    }

    
    public static function crypto_aead_chacha20poly1305_ietf_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_CHACHA20POLY1305_IETF_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_CHACHA20POLY1305_KEYBYTES long');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_aead_chacha20poly1305_ietf_encrypt(
                $plaintext,
                $assocData,
                $nonce,
                $key
            );
        }
        if (self::use_fallback('crypto_aead_chacha20poly1305_ietf_encrypt')) {
            return (string) call_user_func(
                '\\Sodium\\crypto_aead_chacha20poly1305_ietf_encrypt',
                $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
        );
    }

    
    public static function crypto_aead_chacha20poly1305_ietf_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_CHACHA20POLY1305_IETF_KEYBYTES);
    }

    
    public static function crypto_aead_xchacha20poly1305_ietf_decrypt(
        $ciphertext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = '',
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        } else {
            $assocData = '';
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES) {
            throw new SodiumException('Message must be at least CRYPTO_AEAD_XCHACHA20POLY1305_IETF_ABYTES long');
        }
        if (self::useNewSodiumAPI() && !$dontFallback) {
            if (is_callable('sodium_crypto_aead_xchacha20poly1305_ietf_decrypt')) {
                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
        );
    }

    
    public static function crypto_aead_xchacha20poly1305_ietf_encrypt(
        #[\SensitiveParameter]
        $plaintext = '',
        $assocData = '',
        $nonce = '',
        #[\SensitiveParameter]
        $key = '',
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        if (!is_null($assocData)) {
            ParagonIE_Sodium_Core_Util::declareScalarType($assocData, 'string', 2);
        } else {
            $assocData = '';
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_NPUBBYTES) {
            throw new SodiumException('Nonce must be CRYPTO_AEAD_XCHACHA20POLY1305_NPUBBYTES long');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES) {
            throw new SodiumException('Key must be CRYPTO_AEAD_XCHACHA20POLY1305_KEYBYTES long');
        }
        if (self::useNewSodiumAPI() && !$dontFallback) {
            if (is_callable('sodium_crypto_aead_xchacha20poly1305_ietf_encrypt')) {
                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
        );
    }

    
    public static function crypto_aead_xchacha20poly1305_ietf_keygen()
    {
        return random_bytes(self::CRYPTO_AEAD_XCHACHA20POLY1305_IETF_KEYBYTES);
    }

    
    public static function crypto_auth(
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_AUTH_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_auth($message, $key);
        }
        if (self::use_fallback('crypto_auth')) {
            return (string) call_user_func('\\Sodium\\crypto_auth', $message, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::auth($message, $key);
        }
        return ParagonIE_Sodium_Crypto::auth($message, $key);
    }

    
    public static function crypto_auth_keygen()
    {
        return random_bytes(self::CRYPTO_AUTH_KEYBYTES);
    }

    
    public static function crypto_auth_verify(
        $mac,
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($mac, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($mac) !== self::CRYPTO_AUTH_BYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_AUTH_BYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_AUTH_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_AUTH_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_auth_verify($mac, $message, $key);
        }
        if (self::use_fallback('crypto_auth_verify')) {
            return (bool) call_user_func('\\Sodium\\crypto_auth_verify', $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);
    }

    
    public static function crypto_box(
        $plaintext,
        $nonce,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box($plaintext, $nonce, $keypair);
        }
        if (self::use_fallback('crypto_box')) {
            return (string) call_user_func('\\Sodium\\crypto_box', $plaintext, $nonce, $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box($plaintext, $nonce, $keypair);
        }
        return ParagonIE_Sodium_Crypto::box($plaintext, $nonce, $keypair);
    }

    
    public static function crypto_box_seal(
        #[\SensitiveParameter]
        $plaintext,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_seal($plaintext, $publicKey);
        }
        if (self::use_fallback('crypto_box_seal')) {
            return (string) call_user_func('\\Sodium\\crypto_box_seal', $plaintext, $publicKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_seal($plaintext, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::box_seal($plaintext, $publicKey);
    }

    
    public static function crypto_box_seal_open(
        $ciphertext,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_box_seal_open($ciphertext, $keypair);
        }
        if (self::use_fallback('crypto_box_seal_open')) {
            return call_user_func('\\Sodium\\crypto_box_seal_open', $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);
    }

    
    public static function crypto_box_keypair()
    {
        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_keypair();
        }
        if (self::use_fallback('crypto_box_keypair')) {
            return (string) call_user_func('\\Sodium\\crypto_box_keypair');
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_keypair();
        }
        return ParagonIE_Sodium_Crypto::box_keypair();
    }

    
    public static function crypto_box_keypair_from_secretkey_and_publickey(
        #[\SensitiveParameter]
        $secretKey,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_keypair_from_secretkey_and_publickey($secretKey, $publicKey);
        }
        if (self::use_fallback('crypto_box_keypair_from_secretkey_and_publickey')) {
            return (string) call_user_func('\\Sodium\\crypto_box_keypair_from_secretkey_and_publickey', $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);
    }

    
    public static function crypto_box_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($ciphertext) < self::CRYPTO_BOX_MACBYTES) {
            throw new SodiumException('Argument 1 must be at least CRYPTO_BOX_MACBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_BOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_BOX_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_box_open($ciphertext, $nonce, $keypair);
        }
        if (self::use_fallback('crypto_box_open')) {
            return call_user_func('\\Sodium\\crypto_box_open', $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);
    }

    
    public static function crypto_box_publickey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_publickey($keypair);
        }
        if (self::use_fallback('crypto_box_publickey')) {
            return (string) call_user_func('\\Sodium\\crypto_box_publickey', $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_publickey($keypair);
        }
        return ParagonIE_Sodium_Crypto::box_publickey($keypair);
    }

    
    public static function crypto_box_publickey_from_secretkey(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_publickey_from_secretkey($secretKey);
        }
        if (self::use_fallback('crypto_box_publickey_from_secretkey')) {
            return (string) call_user_func('\\Sodium\\crypto_box_publickey_from_secretkey', $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_publickey_from_secretkey($secretKey);
        }
        return ParagonIE_Sodium_Crypto::box_publickey_from_secretkey($secretKey);
    }

    
    public static function crypto_box_secretkey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_BOX_KEYPAIRBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_secretkey($keypair);
        }
        if (self::use_fallback('crypto_box_secretkey')) {
            return (string) call_user_func('\\Sodium\\crypto_box_secretkey', $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_secretkey($keypair);
        }
        return ParagonIE_Sodium_Crypto::box_secretkey($keypair);
    }

    
    public static function crypto_box_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_box_seed_keypair($seed);
        }
        if (self::use_fallback('crypto_box_seed_keypair')) {
            return (string) call_user_func('\\Sodium\\crypto_box_seed_keypair', $seed);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::box_seed_keypair($seed);
        }
        return ParagonIE_Sodium_Crypto::box_seed_keypair($seed);
    }

    
    public static function crypto_generichash(
        $message,
        #[\SensitiveParameter]
        $key = '',
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        if (is_null($key)) {
            $key = '';
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 3);

        /* Input validation: */
        if (!empty($key)) {
            if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
            }
            if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
            }
        }

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_generichash($message, $key, $length);
        }
        if (self::use_fallback('crypto_generichash')) {
            return (string) call_user_func('\\Sodium\\crypto_generichash', $message, $key, $length);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash($message, $key, $length);
        }
        return ParagonIE_Sodium_Crypto::generichash($message, $key, $length);
    }

    
    public static function crypto_generichash_final(
        #[\SensitiveParameter]
        &$ctx,
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ctx, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_generichash_final($ctx, $length);
        }
        if (self::use_fallback('crypto_generichash_final')) {
            $func = '\\Sodium\\crypto_generichash_final';
            return (string) $func($ctx, $length);
        }
        if ($length < 1) {
            try {
                self::memzero($ctx);
            } catch (SodiumException $ex) {
                unset($ctx);
            }
            return '';
        }
        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;
    }

    
    public static function crypto_generichash_init(
        #[\SensitiveParameter]
        $key = '',
        $length = self::CRYPTO_GENERICHASH_BYTES
    ) {
        /* Type checks: */
        if (is_null($key)) {
            $key = '';
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);

        /* Input validation: */
        if (!empty($key)) {
            if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
            }
            if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
            }
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_generichash_init($key, $length);
        }
        if (self::use_fallback('crypto_generichash_init')) {
            return (string) call_user_func('\\Sodium\\crypto_generichash_init', $key, $length);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash_init($key, $length);
        }
        return ParagonIE_Sodium_Crypto::generichash_init($key, $length);
    }

    
    public static function crypto_generichash_init_salt_personal(
        #[\SensitiveParameter]
        $key = '',
        $length = self::CRYPTO_GENERICHASH_BYTES,
        $salt = '',
        $personal = ''
    ) {
        /* Type checks: */
        if (is_null($key)) {
            $key = '';
        }
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($personal, 'string', 4);
        $salt = str_pad($salt, 16, "\0", STR_PAD_RIGHT);
        $personal = str_pad($personal, 16, "\0", STR_PAD_RIGHT);

        /* Input validation: */
        if (!empty($key)) {
            /*
            if (ParagonIE_Sodium_Core_Util::strlen($key) < self::CRYPTO_GENERICHASH_KEYBYTES_MIN) {
                throw new SodiumException('Unsupported key size. Must be at least CRYPTO_GENERICHASH_KEYBYTES_MIN bytes long.');
            }
            */
            if (ParagonIE_Sodium_Core_Util::strlen($key) > self::CRYPTO_GENERICHASH_KEYBYTES_MAX) {
                throw new SodiumException('Unsupported key size. Must be at most CRYPTO_GENERICHASH_KEYBYTES_MAX bytes long.');
            }
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::generichash_init_salt_personal($key, $length, $salt, $personal);
        }
        return ParagonIE_Sodium_Crypto::generichash_init_salt_personal($key, $length, $salt, $personal);
    }

    
    public static function crypto_generichash_update(
        #[\SensitiveParameter]
        &$ctx,
        $message
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ctx, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);

        if (self::useNewSodiumAPI()) {
            sodium_crypto_generichash_update($ctx, $message);
            return;
        }
        if (self::use_fallback('crypto_generichash_update')) {
            $func = '\\Sodium\\crypto_generichash_update';
            $func($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);
        }
    }

    
    public static function crypto_generichash_keygen()
    {
        return random_bytes(self::CRYPTO_GENERICHASH_KEYBYTES);
    }

    
    public static function crypto_kdf_derive_from_key(
        $subkey_len,
        $subkey_id,
        $context,
        #[\SensitiveParameter]
        $key
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($subkey_len, 'int', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($subkey_id, 'int', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($context, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);
        $subkey_id = (int) $subkey_id;
        $subkey_len = (int) $subkey_len;
        $context = (string) $context;
        $key = (string) $key;

        if ($subkey_len < self::CRYPTO_KDF_BYTES_MIN) {
            throw new SodiumException('subkey cannot be smaller than SODIUM_CRYPTO_KDF_BYTES_MIN');
        }
        if ($subkey_len > self::CRYPTO_KDF_BYTES_MAX) {
            throw new SodiumException('subkey cannot be larger than SODIUM_CRYPTO_KDF_BYTES_MAX');
        }
        if ($subkey_id < 0) {
            throw new SodiumException('subkey_id cannot be negative');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($context) !== self::CRYPTO_KDF_CONTEXTBYTES) {
            throw new SodiumException('context should be SODIUM_CRYPTO_KDF_CONTEXTBYTES bytes');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_KDF_KEYBYTES) {
            throw new SodiumException('key should be SODIUM_CRYPTO_KDF_KEYBYTES bytes');
        }

        $salt = ParagonIE_Sodium_Core_Util::store64_le($subkey_id);
        $state = self::crypto_generichash_init_salt_personal(
            $key,
            $subkey_len,
            $salt,
            $context
        );
        return self::crypto_generichash_final($state, $subkey_len);
    }

    
    public static function crypto_kdf_keygen()
    {
        return random_bytes(self::CRYPTO_KDF_KEYBYTES);
    }

    
    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, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($their_public, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($client_public, 'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($server_public, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($my_secret) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($their_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($client_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($server_public) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 4 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI() && !$dontFallback) {
            if (is_callable('sodium_crypto_kx')) {
                return (string) sodium_crypto_kx(
                    $my_secret,
                    $their_public,
                    $client_public,
                    $server_public
                );
            }
        }
        if (self::use_fallback('crypto_kx')) {
            return (string) call_user_func(
                '\\Sodium\\crypto_kx',
                $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
        );
    }

    
    public static function crypto_kx_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);

        $seed = (string) $seed;

        if (ParagonIE_Sodium_Core_Util::strlen($seed) !== self::CRYPTO_KX_SEEDBYTES) {
            throw new SodiumException('seed must be SODIUM_CRYPTO_KX_SEEDBYTES bytes');
        }

        $sk = self::crypto_generichash($seed, '', self::CRYPTO_KX_SECRETKEYBYTES);
        $pk = self::crypto_scalarmult_base($sk);
        return $sk . $pk;
    }

    
    public static function crypto_kx_keypair()
    {
        $sk = self::randombytes_buf(self::CRYPTO_KX_SECRETKEYBYTES);
        $pk = self::crypto_scalarmult_base($sk);
        return $sk . $pk;
    }

    
    public static function crypto_kx_client_session_keys(
        #[\SensitiveParameter]
        $keypair,
        $serverPublicKey
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($serverPublicKey, 'string', 2);

        $keypair = (string) $keypair;
        $serverPublicKey = (string) $serverPublicKey;

        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
            throw new SodiumException('keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($serverPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
            throw new SodiumException('public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes');
        }

        $sk = self::crypto_kx_secretkey($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
            )
        );
    }

    
    public static function crypto_kx_server_session_keys(
        #[\SensitiveParameter]
        $keypair,
        $clientPublicKey
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($clientPublicKey, 'string', 2);

        $keypair = (string) $keypair;
        $clientPublicKey = (string) $clientPublicKey;

        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_KX_KEYPAIRBYTES) {
            throw new SodiumException('keypair should be SODIUM_CRYPTO_KX_KEYPAIRBYTES bytes');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($clientPublicKey) !== self::CRYPTO_KX_PUBLICKEYBYTES) {
            throw new SodiumException('public keys must be SODIUM_CRYPTO_KX_PUBLICKEYBYTES bytes');
        }

        $sk = self::crypto_kx_secretkey($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
            )
        );
    }

    
    public static function crypto_kx_secretkey(
        #[\SensitiveParameter]
        $kp
    ) {
        return ParagonIE_Sodium_Core_Util::substr(
            $kp,
            0,
            self::CRYPTO_KX_SECRETKEYBYTES
        );
    }

    
    public static function crypto_kx_publickey($kp)
    {
        return ParagonIE_Sodium_Core_Util::substr(
            $kp,
            self::CRYPTO_KX_SECRETKEYBYTES,
            self::CRYPTO_KX_PUBLICKEYBYTES
        );
    }

    
    public static function crypto_pwhash(
        $outlen,
        #[\SensitiveParameter]
        $passwd,
        $salt,
        $opslimit,
        $memlimit,
        $alg = null
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($outlen, 'int', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt,  'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 4);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 5);

        if (self::useNewSodiumAPI()) {
            if (!is_null($alg)) {
                ParagonIE_Sodium_Core_Util::declareScalarType($alg, 'int', 6);
                return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit, $alg);
            }
            return sodium_crypto_pwhash($outlen, $passwd, $salt, $opslimit, $memlimit);
        }
        if (self::use_fallback('crypto_pwhash')) {
            return (string) call_user_func('\\Sodium\\crypto_pwhash', $outlen, $passwd, $salt, $opslimit, $memlimit);
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_pwhash_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return true;
        }
        if (self::use_fallback('crypto_pwhash')) {
            return true;
        }
        return false;
    }

    
    public static function crypto_pwhash_str(
        #[\SensitiveParameter]
        $passwd,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_pwhash_str($passwd, $opslimit, $memlimit);
        }
        if (self::use_fallback('crypto_pwhash_str')) {
            return (string) call_user_func('\\Sodium\\crypto_pwhash_str', $passwd, $opslimit, $memlimit);
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_pwhash_str_needs_rehash(
        #[\SensitiveParameter]
        $hash,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);

        // Just grab the first 4 pieces.
        $pieces = explode('$', (string) $hash);
        $prefix = implode('$', array_slice($pieces, 0, 4));

        // Rebuild the expected header.
        
        $ops = (int) $opslimit;
        
        $mem = (int) $memlimit >> 10;
        $encoded = self::CRYPTO_PWHASH_STRPREFIX . 'v=19$m=' . $mem . ',t=' . $ops . ',p=1';

        // Do they match? If so, we don't need to rehash, so return false.
        return !ParagonIE_Sodium_Core_Util::hashEquals($encoded, $prefix);
    }

    
    public static function crypto_pwhash_str_verify(
        #[\SensitiveParameter]
        $passwd,
        #[\SensitiveParameter]
        $hash
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 2);

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_pwhash_str_verify($passwd, $hash);
        }
        if (self::use_fallback('crypto_pwhash_str_verify')) {
            return (bool) call_user_func('\\Sodium\\crypto_pwhash_str_verify', $passwd, $hash);
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Argon2i with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_pwhash_scryptsalsa208sha256(
        $outlen,
        #[\SensitiveParameter]
        $passwd,
        $salt,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($outlen, 'int', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($salt,  'string', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 4);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 5);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_pwhash_scryptsalsa208sha256(
                (int) $outlen,
                (string) $passwd,
                (string) $salt,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256')) {
            return (string) call_user_func(
                '\\Sodium\\crypto_pwhash_scryptsalsa208sha256',
                (int) $outlen,
                (string) $passwd,
                (string) $salt,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_pwhash_scryptsalsa208sha256_is_available()
    {
        if (self::useNewSodiumAPI()) {
            return true;
        }
        if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256')) {
            return true;
        }
        return false;
    }

    
    public static function crypto_pwhash_scryptsalsa208sha256_str(
        #[\SensitiveParameter]
        $passwd,
        $opslimit,
        $memlimit
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($opslimit, 'int', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($memlimit, 'int', 3);

        if (self::useNewSodiumAPI()) {
            return (string) sodium_crypto_pwhash_scryptsalsa208sha256_str(
                (string) $passwd,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256_str')) {
            return (string) call_user_func(
                '\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str',
                (string) $passwd,
                (int) $opslimit,
                (int) $memlimit
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_pwhash_scryptsalsa208sha256_str_verify(
        #[\SensitiveParameter]
        $passwd,
        #[\SensitiveParameter]
        $hash
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($passwd, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($hash, 'string', 2);

        if (self::useNewSodiumAPI()) {
            return (bool) sodium_crypto_pwhash_scryptsalsa208sha256_str_verify(
                (string) $passwd,
                (string) $hash
            );
        }
        if (self::use_fallback('crypto_pwhash_scryptsalsa208sha256_str_verify')) {
            return (bool) call_user_func(
                '\\Sodium\\crypto_pwhash_scryptsalsa208sha256_str_verify',
                (string) $passwd,
                (string) $hash
            );
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented, as it is not possible to implement Scrypt with acceptable performance in pure-PHP'
        );
    }

    
    public static function crypto_scalarmult(
        #[\SensitiveParameter]
        $secretKey,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_BOX_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_BOX_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_scalarmult($secretKey, $publicKey);
        }
        if (self::use_fallback('crypto_scalarmult')) {
            return (string) call_user_func('\\Sodium\\crypto_scalarmult', $secretKey, $publicKey);
        }

        /* Output validation: Forbid all-zero keys */
        if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat("\0", self::CRYPTO_BOX_SECRETKEYBYTES))) {
            throw new SodiumException('Zero secret key is not allowed');
        }
        if (ParagonIE_Sodium_Core_Util::hashEquals($publicKey, str_repeat("\0", self::CRYPTO_BOX_PUBLICKEYBYTES))) {
            throw new SodiumException('Zero public key is not allowed');
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::scalarmult($secretKey, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::scalarmult($secretKey, $publicKey);
    }

    
    public static function crypto_scalarmult_base(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_BOX_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_BOX_SECRETKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_scalarmult_base($secretKey);
        }
        if (self::use_fallback('crypto_scalarmult_base')) {
            return (string) call_user_func('\\Sodium\\crypto_scalarmult_base', $secretKey);
        }
        if (ParagonIE_Sodium_Core_Util::hashEquals($secretKey, str_repeat("\0", self::CRYPTO_BOX_SECRETKEYBYTES))) {
            throw new SodiumException('Zero secret key is not allowed');
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::scalarmult_base($secretKey);
        }
        return ParagonIE_Sodium_Crypto::scalarmult_base($secretKey);
    }

    
    public static function crypto_secretbox(
        #[\SensitiveParameter]
        $plaintext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_secretbox($plaintext, $nonce, $key);
        }
        if (self::use_fallback('crypto_secretbox')) {
            return (string) call_user_func('\\Sodium\\crypto_secretbox', $plaintext, $nonce, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox($plaintext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox($plaintext, $nonce, $key);
    }

    
    public static function crypto_secretbox_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_secretbox_open($ciphertext, $nonce, $key);
        }
        if (self::use_fallback('crypto_secretbox_open')) {
            return call_user_func('\\Sodium\\crypto_secretbox_open', $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);
    }

    
    public static function crypto_secretbox_keygen()
    {
        return random_bytes(self::CRYPTO_SECRETBOX_KEYBYTES);
    }

    
    public static function crypto_secretbox_xchacha20poly1305($plaintext, $nonce, $key)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($plaintext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
        }
        return ParagonIE_Sodium_Crypto::secretbox_xchacha20poly1305($plaintext, $nonce, $key);
    }
    
    public static function crypto_secretbox_xchacha20poly1305_open(
        $ciphertext,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($ciphertext, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_SECRETBOX_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SECRETBOX_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
        }

        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);
    }

    
    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);
    }

    
    public static function crypto_secretstream_xchacha20poly1305_init_pull(
        $header,
        #[\SensitiveParameter]
        $key
    ) {
        if (ParagonIE_Sodium_Core_Util::strlen($header) < self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES) {
            throw new SodiumException(
                'header size should be SODIUM_CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_HEADERBYTES bytes'
            );
        }
        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);
    }

    
    public static function crypto_secretstream_xchacha20poly1305_push(
        #[\SensitiveParameter]
        &$state,
        #[\SensitiveParameter]
        $msg,
        $aad = '',
        $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
        );
    }

    
    public static function crypto_secretstream_xchacha20poly1305_pull(
        #[\SensitiveParameter]
        &$state,
        $msg,
        $aad = ''
    ) {
        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
        );
    }

    
    public static function crypto_secretstream_xchacha20poly1305_keygen()
    {
        return random_bytes(self::CRYPTO_SECRETSTREAM_XCHACHA20POLY1305_KEYBYTES);
    }

    
    public static function crypto_secretstream_xchacha20poly1305_rekey(
        #[\SensitiveParameter]
        &$state
    ) {
        if (PHP_INT_SIZE === 4) {
            ParagonIE_Sodium_Crypto32::secretstream_xchacha20poly1305_rekey($state);
        } else {
            ParagonIE_Sodium_Crypto::secretstream_xchacha20poly1305_rekey($state);
        }
    }

    
    public static function crypto_shorthash(
        $message,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_SHORTHASH_KEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SHORTHASH_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_shorthash($message, $key);
        }
        if (self::use_fallback('crypto_shorthash')) {
            return (string) call_user_func('\\Sodium\\crypto_shorthash', $message, $key);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_SipHash::sipHash24($message, $key);
        }
        return ParagonIE_Sodium_Core_SipHash::sipHash24($message, $key);
    }

    
    public static function crypto_shorthash_keygen()
    {
        return random_bytes(self::CRYPTO_SHORTHASH_KEYBYTES);
    }

    
    public static function crypto_sign(
        $message,
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign($message, $secretKey);
        }
        if (self::use_fallback('crypto_sign')) {
            return (string) call_user_func('\\Sodium\\crypto_sign', $message, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign($message, $secretKey);
        }
        return ParagonIE_Sodium_Crypto::sign($message, $secretKey);
    }

    
    public static function crypto_sign_open(
        $signedMessage,
        $publicKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($signedMessage, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($signedMessage) < self::CRYPTO_SIGN_BYTES) {
            throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_BYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SIGN_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            
            return sodium_crypto_sign_open($signedMessage, $publicKey);
        }
        if (self::use_fallback('crypto_sign_open')) {
            return call_user_func('\\Sodium\\crypto_sign_open', $signedMessage, $publicKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign_open($signedMessage, $publicKey);
        }
        return ParagonIE_Sodium_Crypto::sign_open($signedMessage, $publicKey);
    }

    
    public static function crypto_sign_keypair()
    {
        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_keypair();
        }
        if (self::use_fallback('crypto_sign_keypair')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_keypair');
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::keypair();
        }
        return ParagonIE_Sodium_Core_Ed25519::keypair();
    }

    
    public static function crypto_sign_keypair_from_secretkey_and_publickey(
        #[\SensitiveParameter]
        $sk,
        $pk
    )  {
        ParagonIE_Sodium_Core_Util::declareScalarType($sk, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($pk, 'string', 1);
        $sk = (string) $sk;
        $pk = (string) $pk;

        if (ParagonIE_Sodium_Core_Util::strlen($sk) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException('secretkey should be SODIUM_CRYPTO_SIGN_SECRETKEYBYTES bytes');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($pk) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException('publickey should be SODIUM_CRYPTO_SIGN_PUBLICKEYBYTES bytes');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_keypair_from_secretkey_and_publickey($sk, $pk);
        }
        return $sk . $pk;
    }

    
    public static function crypto_sign_seed_keypair(
        #[\SensitiveParameter]
        $seed
    ) {
        ParagonIE_Sodium_Core_Util::declareScalarType($seed, 'string', 1);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_seed_keypair($seed);
        }
        if (self::use_fallback('crypto_sign_keypair')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_seed_keypair', $seed);
        }
        $publicKey = '';
        $secretKey = '';
        if (PHP_INT_SIZE === 4) {
            ParagonIE_Sodium_Core32_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        } else {
            ParagonIE_Sodium_Core_Ed25519::seed_keypair($publicKey, $secretKey, $seed);
        }
        return $secretKey . $publicKey;
    }

    
    public static function crypto_sign_publickey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_publickey($keypair);
        }
        if (self::use_fallback('crypto_sign_publickey')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_publickey', $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::publickey($keypair);
        }
        return ParagonIE_Sodium_Core_Ed25519::publickey($keypair);
    }

    
    public static function crypto_sign_publickey_from_secretkey(
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_publickey_from_secretkey($secretKey);
        }
        if (self::use_fallback('crypto_sign_publickey_from_secretkey')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_publickey_from_secretkey', $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::publickey_from_secretkey($secretKey);
        }
        return ParagonIE_Sodium_Core_Ed25519::publickey_from_secretkey($secretKey);
    }

    
    public static function crypto_sign_secretkey(
        #[\SensitiveParameter]
        $keypair
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($keypair, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($keypair) !== self::CRYPTO_SIGN_KEYPAIRBYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_SIGN_KEYPAIRBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_secretkey($keypair);
        }
        if (self::use_fallback('crypto_sign_secretkey')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_secretkey', $keypair);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::secretkey($keypair);
        }
        return ParagonIE_Sodium_Core_Ed25519::secretkey($keypair);
    }

    
    public static function crypto_sign_detached(
        $message,
        #[\SensitiveParameter]
        $secretKey
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($secretKey, 'string', 2);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($secretKey) !== self::CRYPTO_SIGN_SECRETKEYBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SIGN_SECRETKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_detached($message, $secretKey);
        }
        if (self::use_fallback('crypto_sign_detached')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_detached', $message, $secretKey);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Crypto32::sign_detached($message, $secretKey);
        }
        return ParagonIE_Sodium_Crypto::sign_detached($message, $secretKey);
    }

    
    public static function crypto_sign_verify_detached($signature, $message, $publicKey)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($signature, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($publicKey, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($signature) !== self::CRYPTO_SIGN_BYTES) {
            throw new SodiumException('Argument 1 must be CRYPTO_SIGN_BYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($publicKey) !== self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SIGN_PUBLICKEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_sign_verify_detached($signature, $message, $publicKey);
        }
        if (self::use_fallback('crypto_sign_verify_detached')) {
            return (bool) call_user_func(
                '\\Sodium\\crypto_sign_verify_detached',
                $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);
    }

    
    public static function crypto_sign_ed25519_pk_to_curve25519($pk)
    {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($pk, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($pk) < self::CRYPTO_SIGN_PUBLICKEYBYTES) {
            throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_PUBLICKEYBYTES long.');
        }
        if (self::useNewSodiumAPI()) {
            if (is_callable('crypto_sign_ed25519_pk_to_curve25519')) {
                return (string) sodium_crypto_sign_ed25519_pk_to_curve25519($pk);
            }
        }
        if (self::use_fallback('crypto_sign_ed25519_pk_to_curve25519')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_ed25519_pk_to_curve25519', $pk);
        }
        if (PHP_INT_SIZE === 4) {
            return ParagonIE_Sodium_Core32_Ed25519::pk_to_curve25519($pk);
        }
        return ParagonIE_Sodium_Core_Ed25519::pk_to_curve25519($pk);
    }

    
    public static function crypto_sign_ed25519_sk_to_curve25519(
        #[\SensitiveParameter]
        $sk
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($sk, 'string', 1);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($sk) < self::CRYPTO_SIGN_SEEDBYTES) {
            throw new SodiumException('Argument 1 must be at least CRYPTO_SIGN_SEEDBYTES long.');
        }
        if (self::useNewSodiumAPI()) {
            if (is_callable('crypto_sign_ed25519_sk_to_curve25519')) {
                return sodium_crypto_sign_ed25519_sk_to_curve25519($sk);
            }
        }
        if (self::use_fallback('crypto_sign_ed25519_sk_to_curve25519')) {
            return (string) call_user_func('\\Sodium\\crypto_sign_ed25519_sk_to_curve25519', $sk);
        }

        $h = hash('sha512', ParagonIE_Sodium_Core_Util::substr($sk, 0, 32), true);
        $h[0] = ParagonIE_Sodium_Core_Util::intToChr(
            ParagonIE_Sodium_Core_Util::chrToInt($h[0]) & 248
        );
        $h[31] = ParagonIE_Sodium_Core_Util::intToChr(
            (ParagonIE_Sodium_Core_Util::chrToInt($h[31]) & 127) | 64
        );
        return ParagonIE_Sodium_Core_Util::substr($h, 0, 32);
    }

    
    public static function crypto_stream(
        $len,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($len, 'int', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_STREAM_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_stream($len, $nonce, $key);
        }
        if (self::use_fallback('crypto_stream')) {
            return (string) call_user_func('\\Sodium\\crypto_stream', $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);
    }

    
    public static function crypto_stream_xor(
        #[\SensitiveParameter]
        $message,
        $nonce,
        #[\SensitiveParameter]
        $key
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_stream_xor($message, $nonce, $key);
        }
        if (self::use_fallback('crypto_stream_xor')) {
            return (string) call_user_func('\\Sodium\\crypto_stream_xor', $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);
    }

    
    public static function crypto_stream_keygen()
    {
        return random_bytes(self::CRYPTO_STREAM_KEYBYTES);
    }


    
    public static function crypto_stream_xchacha20(
        $len,
        $nonce,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($len, 'int', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_STREAM_XCHACHA20_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_stream_xchacha20($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);
    }

    
    public static function crypto_stream_xchacha20_xor(
        #[\SensitiveParameter]
        $message,
        $nonce,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 3);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_XCHACHA20_KEYBYTES long.');
        }

        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_stream_xchacha20_xor($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);
    }

    
    public static function crypto_stream_xchacha20_xor_ic(
        #[\SensitiveParameter]
        $message,
        $nonce,
        $counter,
        #[\SensitiveParameter]
        $key,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($message, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($nonce, 'string', 2);
        ParagonIE_Sodium_Core_Util::declareScalarType($counter, 'int', 3);
        ParagonIE_Sodium_Core_Util::declareScalarType($key, 'string', 4);

        /* Input validation: */
        if (ParagonIE_Sodium_Core_Util::strlen($nonce) !== self::CRYPTO_STREAM_XCHACHA20_NONCEBYTES) {
            throw new SodiumException('Argument 2 must be CRYPTO_SECRETBOX_XCHACHA20_NONCEBYTES long.');
        }
        if (ParagonIE_Sodium_Core_Util::strlen($key) !== self::CRYPTO_STREAM_XCHACHA20_KEYBYTES) {
            throw new SodiumException('Argument 3 must be CRYPTO_SECRETBOX_XCHACHA20_KEYBYTES long.');
        }

        if (is_callable('sodium_crypto_stream_xchacha20_xor_ic') && !$dontFallback) {
            return sodium_crypto_stream_xchacha20_xor_ic($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);
    }

    
    public static function crypto_stream_xchacha20_keygen()
    {
        return random_bytes(self::CRYPTO_STREAM_XCHACHA20_KEYBYTES);
    }

    
    public static function hex2bin(
        #[\SensitiveParameter]
        $string,
        $ignore = ''
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($string, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($ignore, 'string', 2);

        if (self::useNewSodiumAPI()) {
            if (is_callable('sodium_hex2bin')) {
                return (string) sodium_hex2bin($string, $ignore);
            }
        }
        if (self::use_fallback('hex2bin')) {
            return (string) call_user_func('\\Sodium\\hex2bin', $string, $ignore);
        }
        return ParagonIE_Sodium_Core_Util::hex2bin($string, $ignore);
    }

    
    public static function increment(
        #[\SensitiveParameter]
        &$var
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($var, 'string', 1);

        if (self::useNewSodiumAPI()) {
            sodium_increment($var);
            return;
        }
        if (self::use_fallback('increment')) {
            $func = '\\Sodium\\increment';
            $func($var);
            return;
        }

        $len = ParagonIE_Sodium_Core_Util::strlen($var);
        $c = 1;
        $copy = '';
        for ($i = 0; $i < $len; ++$i) {
            $c += ParagonIE_Sodium_Core_Util::chrToInt(
                ParagonIE_Sodium_Core_Util::substr($var, $i, 1)
            );
            $copy .= ParagonIE_Sodium_Core_Util::intToChr($c);
            $c >>= 8;
        }
        $var = $copy;
    }

    
    public static function is_zero(
        #[\SensitiveParameter]
        $str
    ) {
        $d = 0;
        for ($i = 0; $i < 32; ++$i) {
            $d |= ParagonIE_Sodium_Core_Util::chrToInt($str[$i]);
        }
        return ((($d - 1) >> 31) & 1) === 1;
    }

    
    public static function library_version_major()
    {
        if (self::useNewSodiumAPI() && defined('SODIUM_LIBRARY_MAJOR_VERSION')) {
            return SODIUM_LIBRARY_MAJOR_VERSION;
        }
        if (self::use_fallback('library_version_major')) {
            
            return (int) call_user_func('\\Sodium\\library_version_major');
        }
        return self::LIBRARY_VERSION_MAJOR;
    }

    
    public static function library_version_minor()
    {
        if (self::useNewSodiumAPI() && defined('SODIUM_LIBRARY_MINOR_VERSION')) {
            return SODIUM_LIBRARY_MINOR_VERSION;
        }
        if (self::use_fallback('library_version_minor')) {
            
            return (int) call_user_func('\\Sodium\\library_version_minor');
        }
        return self::LIBRARY_VERSION_MINOR;
    }

    
    public static function memcmp(
        #[\SensitiveParameter]
        $left,
        #[\SensitiveParameter]
        $right
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($left, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($right, 'string', 2);

        if (self::useNewSodiumAPI()) {
            return sodium_memcmp($left, $right);
        }
        if (self::use_fallback('memcmp')) {
            return (int) call_user_func('\\Sodium\\memcmp', $left, $right);
        }
        
        
        return ParagonIE_Sodium_Core_Util::memcmp($left, $right);
    }

    
    public static function memzero(
        #[\SensitiveParameter]
        &$var
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($var, 'string', 1);

        if (self::useNewSodiumAPI()) {
            
            sodium_memzero($var);
            return;
        }
        if (self::use_fallback('memzero')) {
            $func = '\\Sodium\\memzero';
            $func($var);
            if ($var === null) {
                return;
            }
        }
        // This is the best we can do.
        throw new SodiumException(
            'This is not implemented in sodium_compat, as it is not possible to securely wipe memory from PHP. ' .
            'To fix this error, make sure libsodium is installed and the PHP extension is enabled.'
        );
    }

    
    public static function pad(
        #[\SensitiveParameter]
        $unpadded,
        $blockSize,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($unpadded, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, 'int', 2);

        $unpadded = (string) $unpadded;
        $blockSize = (int) $blockSize;

        if (self::useNewSodiumAPI() && !$dontFallback) {
            return (string) sodium_pad($unpadded, $blockSize);
        }

        if ($blockSize <= 0) {
            throw new SodiumException(
                'block size cannot be less than 1'
            );
        }
        $unpadded_len = ParagonIE_Sodium_Core_Util::strlen($unpadded);
        $xpadlen = ($blockSize - 1);
        if (($blockSize & ($blockSize - 1)) === 0) {
            $xpadlen -= $unpadded_len & ($blockSize - 1);
        } else {
            $xpadlen -= $unpadded_len % $blockSize;
        }

        $xpadded_len = $unpadded_len + $xpadlen;
        $padded = str_repeat("\0", $xpadded_len - 1);
        if ($unpadded_len > 0) {
            $st = 1;
            $i = 0;
            $k = $unpadded_len;
            for ($j = 0; $j <= $xpadded_len; ++$j) {
                $i = (int) $i;
                $k = (int) $k;
                $st = (int) $st;
                if ($j >= $unpadded_len) {
                    $padded[$j] = "\0";
                } else {
                    $padded[$j] = $unpadded[$j];
                }
                
                $k -= $st;
                $st = (int) (~(
                            (
                                (
                                    ($k >> 48)
                                        |
                                    ($k >> 32)
                                        |
                                    ($k >> 16)
                                        |
                                    $k
                                ) - 1
                            ) >> 16
                        )
                    ) & 1;
                $i += $st;
            }
        }

        $mask = 0;
        $tail = $xpadded_len;
        for ($i = 0; $i < $blockSize; ++$i) {
            # barrier_mask = (unsigned char)
            #     (((i ^ xpadlen) - 1U) >> ((sizeof(size_t) - 1U) * CHAR_BIT));
            $barrier_mask = (($i ^ $xpadlen) -1) >> ((PHP_INT_SIZE << 3) - 1);
            # tail[-i] = (tail[-i] & mask) | (0x80 & barrier_mask);
            $padded[$tail - $i] = ParagonIE_Sodium_Core_Util::intToChr(
                (ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]) & $mask)
                    |
                (0x80 & $barrier_mask)
            );
            # mask |= barrier_mask;
            $mask |= $barrier_mask;
        }
        return $padded;
    }

    
    public static function unpad(
        #[\SensitiveParameter]
        $padded,
        $blockSize,
        $dontFallback = false
    ) {
        /* Type checks: */
        ParagonIE_Sodium_Core_Util::declareScalarType($padded, 'string', 1);
        ParagonIE_Sodium_Core_Util::declareScalarType($blockSize, 'int', 2);

        $padded = (string) $padded;
        $blockSize = (int) $blockSize;

        if (self::useNewSodiumAPI() && !$dontFallback) {
            return (string) sodium_unpad($padded, $blockSize);
        }
        if ($blockSize <= 0) {
            throw new SodiumException('block size cannot be less than 1');
        }
        $padded_len = ParagonIE_Sodium_Core_Util::strlen($padded);
        if ($padded_len < $blockSize) {
            throw new SodiumException('invalid padding');
        }

        # tail = &padded[padded_len - 1U];
        $tail = $padded_len - 1;

        $acc = 0;
        $valid = 0;
        $pad_len = 0;

        $found = 0;
        for ($i = 0; $i < $blockSize; ++$i) {
            # c = tail[-i];
            $c = ParagonIE_Sodium_Core_Util::chrToInt($padded[$tail - $i]);

            # is_barrier =
            #     (( (acc - 1U) & (pad_len - 1U) & ((c ^ 0x80) - 1U) ) >> 8) & 1U;
            $is_barrier = (
                (
                    ($acc - 1) & ($pad_len - 1) & (($c ^ 80) - 1)
                ) >> 7
            ) & 1;
            $is_barrier &= ~$found;
            $found |= $is_barrier;

            # acc |= c;
            $acc |= $c;

            # pad_len |= i & (1U + ~is_barrier);
            $pad_len |= $i & (1 + ~$is_barrier);

            # valid |= (unsigned char) is_barrier;
            $valid |= ($is_barrier & 0xff);
        }
        # unpadded_len = padded_len - 1U - pad_len;
        $unpadded_len = $padded_len - 1 - $pad_len;
        if ($valid !== 1) {
            throw new SodiumException('invalid padding');
        }
        return ParagonIE_Sodium_Core_Util::substr($padded, 0, $unpadded_len);
    }

    
    public static function polyfill_is_fast()
    {
        if (extension_loaded('sodium')) {
            return true;
        }
        if (extension_loaded('libsodium')) {
            return true;
        }
        return PHP_INT_SIZE === 8;
    }

    
    public static function randombytes_buf($numBytes)
    {
        /* Type checks: */
        if (!is_int($numBytes)) {
            if (is_numeric($numBytes)) {
                $numBytes = (int) $numBytes;
            } else {
                throw new TypeError(
                    'Argument 1 must be an integer, ' . gettype($numBytes) . ' given.'
                );
            }
        }
        
        if (self::use_fallback('randombytes_buf')) {
            return (string) call_user_func('\\Sodium\\randombytes_buf', $numBytes);
        }
        if ($numBytes < 0) {
            throw new SodiumException("Number of bytes must be a positive integer");
        }
        return random_bytes($numBytes);
    }

    
    public static function randombytes_uniform($range)
    {
        /* Type checks: */
        if (!is_int($range)) {
            if (is_numeric($range)) {
                $range = (int) $range;
            } else {
                throw new TypeError(
                    'Argument 1 must be an integer, ' . gettype($range) . ' given.'
                );
            }
        }
        if (self::use_fallback('randombytes_uniform')) {
            return (int) call_user_func('\\Sodium\\randombytes_uniform', $range);
        }
        return random_int(0, $range - 1);
    }

    
    public static function randombytes_random16()
    {
        if (self::use_fallback('randombytes_random16')) {
            return (int) call_user_func('\\Sodium\\randombytes_random16');
        }
        return random_int(0, 65535);
    }

    
    public static function ristretto255_is_valid_point(
        #[\SensitiveParameter]
        $p,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_is_valid_point($p);
        }
        try {
            $r = ParagonIE_Sodium_Core_Ristretto255::ristretto255_frombytes($p);
            return $r['res'] === 0 &&
                ParagonIE_Sodium_Core_Ristretto255::ristretto255_point_is_canonical($p) === 1;
        } catch (SodiumException $ex) {
            if ($ex->getMessage() === 'S is not canonical') {
                return false;
            }
            throw $ex;
        }
    }

    
    public static function ristretto255_add(
        #[\SensitiveParameter]
        $p,
        #[\SensitiveParameter]
        $q,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_add($p, $q);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_add($p, $q);
    }

    
    public static function ristretto255_sub(
        #[\SensitiveParameter]
        $p,
        #[\SensitiveParameter]
        $q,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_sub($p, $q);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_sub($p, $q);
    }

    
    public static function ristretto255_from_hash(
        #[\SensitiveParameter]
        $r,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_from_hash($r);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_from_hash($r);
    }

    
    public static function ristretto255_random($dontFallback = false)
    {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_random();
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_random();
    }

    
    public static function ristretto255_scalar_random($dontFallback = false)
    {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_random();
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_random();
    }

    
    public static function ristretto255_scalar_invert(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_invert($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_invert($s);
    }
    
    public static function ristretto255_scalar_negate(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_negate($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_negate($s);
    }

    
    public static function ristretto255_scalar_complement(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_complement($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_complement($s);
    }

    
    public static function ristretto255_scalar_add(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_add($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_add($x, $y);
    }

    
    public static function ristretto255_scalar_sub(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_sub($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_sub($x, $y);
    }

    
    public static function ristretto255_scalar_mul(
        #[\SensitiveParameter]
        $x,
        #[\SensitiveParameter]
        $y,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_mul($x, $y);
        }
        return ParagonIE_Sodium_Core_Ristretto255::ristretto255_scalar_mul($x, $y);
    }

    
    public static function scalarmult_ristretto255(
        #[\SensitiveParameter]
        $n,
        #[\SensitiveParameter]
        $p,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_scalarmult_ristretto255($n, $p);
        }
        return ParagonIE_Sodium_Core_Ristretto255::scalarmult_ristretto255($n, $p);
    }

    
    public static function scalarmult_ristretto255_base(
        #[\SensitiveParameter]
        $n,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_scalarmult_ristretto255_base($n);
        }
        return ParagonIE_Sodium_Core_Ristretto255::scalarmult_ristretto255_base($n);
    }

    
    public static function ristretto255_scalar_reduce(
        #[\SensitiveParameter]
        $s,
        $dontFallback = false
    ) {
        if (self::useNewSodiumAPI() && !$dontFallback) {
            return sodium_crypto_core_ristretto255_scalar_reduce($s);
        }
        return ParagonIE_Sodium_Core_Ristretto255::sc_reduce($s);
    }

    
    public static function runtime_speed_test($iterations, $maxTimeout)
    {
        if (self::polyfill_is_fast()) {
            return true;
        }
        
        $end = 0.0;
        
        $start = microtime(true);
        
        $a = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 << 16));
        for ($i = 0; $i < $iterations; ++$i) {
            
            $b = ParagonIE_Sodium_Core32_Int64::fromInt(random_int(3, 1 << 16));
            $a->mulInt64($b);
        }
        
        $end = microtime(true);
        
        $diff = (int) ceil(($end - $start) * 1000);
        return $diff < $maxTimeout;
    }

    
    public static function sub(
        #[\SensitiveParameter]
        &$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('values must have the same length');
        }
        $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);
        $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);

        $c = 0;
        for ($i = 0; $i < $val_len; $i++) {
            $c = ($A[$i] - $B[$i] - $c);
            $A[$i] = ($c & 0xff);
            $c = ($c >> 8) & 1;
        }
        $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);
    }

    
    public static function version_string()
    {
        if (self::useNewSodiumAPI()) {
            return (string) sodium_version_string();
        }
        if (self::use_fallback('version_string')) {
            return (string) call_user_func('\\Sodium\\version_string');
        }
        return (string) self::VERSION_STRING;
    }

    
    protected static function use_fallback($sodium_func_name = '')
    {
        static $res = null;
        if ($res === null) {
            $res = extension_loaded('libsodium') && PHP_VERSION_ID >= 50300;
        }
        if ($res === false) {
            // No libsodium installed
            return false;
        }
        if (self::$disableFallbackForUnitTests) {
            // Don't fallback. Use the PHP implementation.
            return false;
        }
        if (!empty($sodium_func_name)) {
            return is_callable('\\Sodium\\' . $sodium_func_name);
        }
        return true;
    }

    
    protected static function useNewSodiumAPI()
    {
        static $res = null;
        if ($res === null) {
            $res = PHP_VERSION_ID >= 70000 && extension_loaded('sodium');
        }
        if (self::$disableFallbackForUnitTests) {
            // Don't fallback. Use the PHP implementation.
            return false;
        }
        return (bool) $res;
    }
}