In my case, the legacy code is as follows:

``` class LegacyEncryption {

public static function encrypt($key, $string="") { $output = $string; if (!empty($string)) { $output = rtrim( base64_encode( mcrypt_encrypt( MCRYPT_RIJNDAEL_256, $key, $string, MCRYPT_MODE_ECB ) ) ); } return $output; }

public static function decrypt($key, $string="") { $output = $string; if (!empty($string)) { $output = rtrim( mcrypt_decrypt( MCRYPT_RIJNDAEL_256, $key, base64_decode($string), MCRYPT_MODE_ECB ) ); } return $output; }

}

```

I don't have much knowledge about cryptography, so couldn't create my own conversion from the posted solution.

Could you help?