Encrypt in PHP 7 decrypt in Node JS

Question

In PHP 5.6 there were plenty of solutions that worked perfectly that were based on http://php.net/manual/en/function.mcrypt-decrypt.php

For example

public function encrypt($data)
{
    //don't use default php padding which is '\0'
    $pad = $this->blocksize - (strlen($data) % $this->blocksize);
    $data = $data . str_repeat(chr($pad), $pad);
    return bin2hex(mcrypt_encrypt(MCRYPT_RIJNDAEL_128,
        $this->encryptKey,
        $data, MCRYPT_MODE_CBC, $this->iv));
}

But PHP7 has a WARNING that discourages using this function.

"This function has been DEPRECATED as of PHP 7.1.0. Relying on this function is highly discouraged."

Any ideas for safe encryption using keywords on both ends; PHP + Node.js?

Answer 1

LibMcrypt was abandoned in 2007. More information https://wiki.php.net/rfc/mcrypt-viking-funeral

You have to use openssl encrypt http://php.net/manual/en/function.openssl-encrypt.php

PHP

<?php
$textToEncrypt = "Secret Text to Encrypt";
$encryptionMethod = 'aes-256-cbc';
$secretHash = "315a5504d921f8327f73a356d2bbcbf1"; // <---- you have to use some persistent key.

$iv_size = openssl_cipher_iv_length($encryptionMethod);
$iv = openssl_random_pseudo_bytes($iv_size);

//To encrypt
$encryptedMessage = openssl_encrypt($textToEncrypt, $encryptionMethod, $secretHash, 0, $iv);

//Concatenate iv with data
$encryptedMessageWithIv = bin2hex($iv) . $encryptedMessage;

//To Decrypt
$iv_size = openssl_cipher_iv_length($encryptionMethod);
$iv = hex2bin(substr($encryptedMessageWithIv, 0, $iv_size * 2));

$decryptedMessage = openssl_decrypt(substr($encryptedMessageWithIv, $iv_size * 2), $encryptionMethod, $secretHash, 0, $iv);

echo "Encrypted: $encryptedMessageWithIv <br>Decrypted: $decryptedMessage";

Try it here https://3v4l.org/r9pYv

Node.JS (i really not a node.js programmer, there can be more efficient way)

var data = "ad699a2537ec2a7f699acbf97ca0080eh3z5EgvnTAvlc76YeR6HdWPmkDDt+pHiG//qo7xnqyQ=";
var key = "315a5504d921f8327f73a356d2bbcbf1";
var iv = new Buffer(data.substring(0,32), 'hex');
var dec = crypto.createDecipheriv('aes-256-cbc',key,iv);
var decrypted = Buffer.concat([dec.update(new Buffer(data.substring(32),'base64')), dec.final()]);
console.log('DECRYPTED TEXT: '+decrypted.toString());

Try here: https://repl.it/FQyo/2