gistfile1.txt

private function encrypt($message, $key, $encode = true) {
        $method = 'aes-256-ctr';

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

        $cipherText = openssl_encrypt(
            $message,
            $method,
            $key,
            OPENSSL_RAW_DATA,
            $iv
        );

        if ($encode) {
            return base64_encode($iv.$cipherText);
        }

        return $iv.$cipherText;
    }

    private function decrypt($message, $key, $encoded = true) {
        $method = 'aes-256-ctr';

        if($encoded) {
            $message = base64_decode($message, true);
            if($message === false) {
                throw new Exception('Encryption fail at base64_decode');
            }
        }

        $ivSize = openssl_cipher_iv_length($method);
        $iv = mb_substr($message, 0, $ivSize, '8bit');
        $cipherText = mb_substr($message, $ivSize, null, '8bit');

        $plainText = openssl_decrypt(
            $cipherText,
            $method,
            $key,
            OPENSSL_RAW_DATA,
            $iv
        );

        return $plainText;
    }