This whitepaper is called Local Session Poisoning in PHP Part 3: Bypassing Suhosin’s Session Encryption.
You can download it from the following link: https://packetstormsecurity.com/files/download/105785/php-part3.pdf
Source: https://packetstormsecurity.com/files/105785/Local-Session-Poisoning-In-PHP-Part-3.html