vanilla / garden

     * @param bool $throw Whether or not to throw an exception on error.

     * @return string Returns the encrypted string.

     */

    protected function encrypt($str, $method, $password, $iv = '', $throw = false) {

        if ($iv === '') {

            $iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length($method));

        }

        // Encrypt the string.

        $encrypted = openssl_encrypt($str, $method, $password, OPENSSL_RAW_DATA, $iv);

        if ($encrypted === false) {

            return $this->exception($throw, "Error encrypting the string.", 400);

        }

        $str = static::base64urlEncode($encrypted);

        $this->pushString($str, static::base64urlEncode($iv));

        return $str;

    }

    /**

     * Decrypt a string with {@link openssl_decrypt()}.

     * @param bool $throw Whether or not the throw an exception on error.

     * @return string Returns the string with signing information or null on error.

     */

    protected function hmac($str, $method, $password, $timestamp = 0, $throw = false) {

        if ($timestamp === 0) {

            $timestamp = time();

        }

        // Add the timestamp to the string.

        static::pushString($str, $timestamp);

        // Sign the string.

        $signature = hash_hmac($method, $str, $password, true);

        if ($signature === false) {

            return $this->exception($throw, "Invalid hash method $method.", 400);

        }

        // Add the signature to the string.

        static::pushString($str, static::base64urlEncode($signature));

        return $str;

    }

    /**

     * Verify the signature on a secure string.