- rtrim: documentation ( source)
- base64_decode: documentation ( source)
<?php
$cookie = "lZCqNoEVm1xjBan01HZYv6hf9zAS3NK3VmaSOC3ENL3B5db6zSURkVVo+xv9ZLLwEXNfonxG60/B78gCOBGM04TzfR8hKa4KSCJlnEa3Vv8=";
$secret_key = "11111111";
$secreto_revelado = rtrim(mcrypt_decrypt(MCRYPT_DES, $secret_key, base64_decode($cookie), MCRYPT_MODE_ECB),"\0");
print rtrim($secreto_revelado,"\0");
print strlen($secreto_revelado);