Re: Encrypt and decrypt cookie

I am not a specialist, but I discovered the parameter iv and the related function create_iv. Most likely you must provide an created iv before encryption, store the cypher and the iv together in the cookie and at retreaval, use both in decrypt. So in between: /* Terminate encryption handler */ mcrypt_generic_deinit ($td); /* Initialize encryption module for decryption */ mcrypt_generic_init ($td, $key, $iv); you store and retreave from the cookie both $iv and $td. $key must be on your server. $iv must be some random stuff that changes between encryption and decryption (between sessions). Play with it and you will find out.