Encoding\Decoding in php?

Question

PHP

Please tell me, there is a need to encode \ decode a string,
as an example, it is desirable that it be in this form:

$key = "Ключ для шифрования";
$string = "Строка которую нужно зашифровать";
//Зашифровываем строку 
$cipher= function XXX ($key, $string,);
//Расшифровываем строку
$itog = function XXX ($key, $cipher);

I read about Mcrypt, but it requires installation on the server, which is not allowed. Does anyone have any thoughts on this?

Answer 1

Here is an interesting article: habrahabr.ru/sandbox/92985