PHP AES Encryption and Decryption Using OpenSSL

AES encryption in PHP5 used the mcrypt_decrypt function, which has been deprecated after PHP 7.1; the modern replacement is OpenSSL's openssl_encrypt and openssl_decrypt. The following compact class implements both operations.

<?php
class Aes {
    public $key = '';
    public $iv = '';
    public function __construct($config) {
        foreach ($config as $k => $v) {
            $this->$k = $v;
        }
    }
    // Encryption
    public function aesEn($data) {
        return base64_encode(openssl_encrypt($data, $this->method, $this->key, OPENSSL_RAW_DATA, $this->iv));
    }
    // Decryption
    public function aesDe($data) {
        return openssl_decrypt(base64_decode($data), $this->method, $this->key, OPENSSL_RAW_DATA, $this->iv);
    }
}
?>

The class is configured with an associative array specifying the encryption key, a 16‑byte IV generated via md5(time().uniqid(), true), and the method (e.g., 'AES-128-CBC').

<?php
$config = [
    // encryption key
    'key' => 'aaaabbbbcccc',
    // ensure IV is 16 bytes
    'iv' => md5(time().uniqid(), true),
    // encryption method
    'method' => 'AES-128-CBC',
];

$obj = new Aes($config);
$res = $obj->aesEn('123456789');
// encrypted data
echo $res;
?>

To decrypt, instantiate the class with the same configuration and call aesDe on the encrypted string.

<?php
$obj = new Aes($config);
$decrypted = $obj->aesDe($res);
echo $decrypted; // outputs original data
?>

This approach allows developers to hide sensitive parameters and data by encrypting them before transmission, ensuring that only the backend can decrypt and process the original information.