opencart 1.5.6.4 PHP 7.2+

encryption.php

<?php
final class Encryption {
	private $key;
	
	public function __construct($key) {
		$this->key = hash('sha256', $key, true);
	}
	
	public function encrypt($value) {
		return strtr(base64_encode(openssl_encrypt($value, 'aes-128-cbc', $this->key)), '+/=', '-_,');
	}
	
	public function decrypt($value) {
		return trim(openssl_decrypt(base64_decode(strtr($value, '-_,', '+/=')), 'aes-128-cbc', $this->key));
	}
}