- var_dump: documentation ( source)
- base64_decode: documentation ( source)
- unserialize: documentation ( source)
<?php
$signed_string = 'a:4:{s:28:"Tzo4OiJzdGRDbGFzcyI6MDp7fQ==";s:1:"1";s:9:"adminhash";N;s:4:"ajax";N;s:8:"postvars";N;}';
var_dump($signed_string, base64_decode($signed_string), unserialize(base64_decode($signed_string)));