Wordpress login cookie creation through django

I am trying to integrate wordpress into django. What I am planning is to create the wp user table using django and when a person logs into django, I will create a wordpress cookie with username%expiry%md5ofphpasshash to create it. To experiment that this method works, i installed cookie plugin(edit cookie) for chrome and logged into the site. I was able to modify the hash and still able to sustain logged in state. But the problem is with the expiry. A sample cookie looks like this. The current epoch time is 1366518444 Cookie contents from login: admin%7C1366690893%7C9d0c3062da26fd5c67c874f390e32c28 When I modify the second field 7C1366690893 even by a second I get logged out although it is far ahead of the epoch time. Why am I getting logged out, does wordpress remember the expiry time or is this some setting error? Please help. This is the only problem that is stopping me from single login.

To recreate the problem I am trying to solve, login to a wordpress site. Open any cookie edit software. Find the wordpress_logged_in_adfaljewe322423**** cookie. Modify the timestamp by a second or so. The time stamp is the field after the first occurence of %7C. Now save the cookie and refresh the page, you should be logged out of the site. Please tell me how to solve this. If I can’t get the logic behind the timestamp, i cannot make single login possible.
admin%7C1366690893%7C9d0c3062da26fd5c67c874f390e32c28