public static function hashPassword($password)
    {
        # Test the message and key for string validity.
        Helpers::isString($password, 'Hash', 'hashPassword');

        return \Sodium\crypto_pwhash_scryptsalsa208sha256_str(
            $password,
            Constants::PWHASH_SCRYPTSALSA208SHA256_OPSLIMIT_INTERACTIVE,
            Constants::PWHASH_SCRYPTSALSA208SHA256_MEMLIMIT_INTERACTIVE
        );
    }