ParagonIE_Sodium_Compat::crypto_pwhash_scryptsalsa208sha256_str

    public static function crypto_pwhash_scryptsalsa208sha256_str($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'
        );
    }