Weak everyday security

June 26, 2009

Ever own a Ford or Lincoln car with one of those keypad entry systems. They usually have 5 buttons, each with two numbers on them. 1/2, 3/4, 5/6, 7/8, 9/0 If you’ve ever owned one, you probably know that pressing the last two buttons locks the doors. Yes, this is the same on every single car I’ve ever seen with this system. Another thing you may not realize is that it uses a rolling input buffer for screening your input. Lets call these buttons by their first digit for ease of analysis.

keypad


So we have buttons 1, 3, 5, 7, 9. Now each code is 5 digits long. Now whats interesting is if we enter 31715791, we’ve just tried 4 different unlock codes – 31715, 17157, 71579, and 15791. If we continue this process each additional key press will attempt a new combination. Simple math tells us that there are only 3125 ( 55 ) possible combinations. So, we should be able to accomplish every combination in 4 + 3125 key presses using a mathematical process developed by Nicolaas Govert de Bruijn. Anyway, enough about the math behind this… here is the sequence. 3129 keypress. If you can manage about 3 every 2 seconds it should take you a maximum of about 30 minutes to find the sequence. Obviously this is for educational purposes only!

9 9 9 9 1 1 1 1 1 3 1 1 1 1 5 1 1 1 1 7 1 1 1 1 9 1 1 1 3 3 1 1 1 3 5 1 1 1 3 7 1 1 1 3 9 1 1 1 5 3 1 1 1 5 5 1 1 1 5 7 1 1 1 5 9 1 1 1 7 3 1 1 1 7 5 1 1 1 7 7 1 1 1 7 9 1 1 1 9 3 1 1 1 9 5 1 1 1 9 7 1 1 1 9 9 1 1 3 1 3 1 1 3 1 5 1 1 3 1 7 1 1 3 1 9 1 1 3 3 3 1 1 3 3 5 1 1 3 3 7 1 1 3 3 9 1 1 3 5 3 1 1 3 5 5 1 1 3 5 7 1 1 3 5 9 1 1 3 7 3 1 1 3 7 5 1 1 3 7 7 1 1 3 7 9 1 1 3 9 3 1 1 3 9 5 1 1 3 9 7 1 1 3 9 9 1 1 5 1 3 1 1 5 1 5 1 1 5 1 7 1 1 5 1 9 1 1 5 3 3 1 1 5 3 5 1 1 5 3 7 1 1 5 3 9 1 1 5 5 3 1 1 5 5 5 1 1 5 5 7 1 1 5 5 9 1 1 5 7 3 1 1 5 7 5 1 1 5 7 7 1 1 5 7 9 1 1 5 9 3 1 1 5 9 5 1 1 5 9 7 1 1 5 9 9 1 1 7 1 3 1 1 7 1 5 1 1 7 1 7 1 1 7 1 9 1 1 7 3 3 1 1 7 3 5 1 1 7 3 7 1 1 7 3 9 1 1 7 5 3 1 1 7 5 5 1 1 7 5 7 1 1 7 5 9 1 1 7 7 3 1 1 7 7 5 1 1 7 7 7 1 1 7 7 9 1 1 7 9 3 1 1 7 9 5 1 1 7 9 7 1 1 7 9 9 1 1 9 1 3 1 1 9 1 5 1 1 9 1 7 1 1 9 1 9 1 1 9 3 3 1 1 9 3 5 1 1 9 3 7 1 1 9 3 9 1 1 9 5 3 1 1 9 5 5 1 1 9 5 7 1 1 9 5 9 1 1 9 7 3 1 1 9 7 5 1 1 9 7 7 1 1 9 7 9 1 1 9 9 3 1 1 9 9 5 1 1 9 9 7 1 1 9 9 9 1 3 1 3 3 1 3 1 3 5 1 3 1 3 7 1 3 1 3 9 1 3 1 5 3 1 3 1 5 5 1 3 1 5 7 1 3 1 5 9 1 3 1 7 3 1 3 1 7 5 1 3 1 7 7 1 3 1 7 9 1 3 1 9 3 1 3 1 9 5 1 3 1 9 7 1 3 1 9 9 1 3 3 1 5 1 3 3 1 7 1 3 3 1 9 1 3 3 3 3 1 3 3 3 5 1 3 3 3 7 1 3 3 3 9 1 3 3 5 3 1 3 3 5 5 1 3 3 5 7 1 3 3 5 9 1 3 3 7 3 1 3 3 7 5 1 3 3 7 7 1 3 3 7 9 1 3 3 9 3 1 3 3 9 5 1 3 3 9 7 1 3 3 9 9 1 3 5 1 5 1 3 5 1 7 1 3 5 1 9 1 3 5 3 3 1 3 5 3 5 1 3 5 3 7 1 3 5 3 9 1 3 5 5 3 1 3 5 5 5 1 3 5 5 7 1 3 5 5 9 1 3 5 7 3 1 3 5 7 5 1 3 5 7 7 1 3 5 7 9 1 3 5 9 3 1 3 5 9 5 1 3 5 9 7 1 3 5 9 9 1 3 7 1 5 1 3 7 1 7 1 3 7 1 9 1 3 7 3 3 1 3 7 3 5 1 3 7 3 7 1 3 7 3 9 1 3 7 5 3 1 3 7 5 5 1 3 7 5 7 1 3 7 5 9 1 3 7 7 3 1 3 7 7 5 1 3 7 7 7 1 3 7 7 9 1 3 7 9 3 1 3 7 9 5 1 3 7 9 7 1 3 7 9 9 1 3 9 1 5 1 3 9 1 7 1 3 9 1 9 1 3 9 3 3 1 3 9 3 5 1 3 9 3 7 1 3 9 3 9 1 3 9 5 3 1 3 9 5 5 1 3 9 5 7 1 3 9 5 9 1 3 9 7 3 1 3 9 7 5 1 3 9 7 7 1 3 9 7 9 1 3 9 9 3 1 3 9 9 5 1 3 9 9 7 1 3 9 9 9 1 5 1 5 3 1 5 1 5 5 1 5 1 5 7 1 5 1 5 9 1 5 1 7 3 1 5 1 7 5 1 5 1 7 7 1 5 1 7 9 1 5 1 9 3 1 5 1 9 5 1 5 1 9 7 1 5 1 9 9 1 5 3 1 7 1 5 3 1 9 1 5 3 3 3 1 5 3 3 5 1 5 3 3 7 1 5 3 3 9 1 5 3 5 3 1 5 3 5 5 1 5 3 5 7 1 5 3 5 9 1 5 3 7 3 1 5 3 7 5 1 5 3 7 7 1 5 3 7 9 1 5 3 9 3 1 5 3 9 5 1 5 3 9 7 1 5 3 9 9 1 5 5 1 7 1 5 5 1 9 1 5 5 3 3 1 5 5 3 5 1 5 5 3 7 1 5 5 3 9 1 5 5 5 3 1 5 5 5 5 1 5 5 5 7 1 5 5 5 9 1 5 5 7 3 1 5 5 7 5 1 5 5 7 7 1 5 5 7 9 1 5 5 9 3 1 5 5 9 5 1 5 5 9 7 1 5 5 9 9 1 5 7 1 7 1 5 7 1 9 1 5 7 3 3 1 5 7 3 5 1 5 7 3 7 1 5 7 3 9 1 5 7 5 3 1 5 7 5 5 1 5 7 5 7 1 5 7 5 9 1 5 7 7 3 1 5 7 7 5 1 5 7 7 7 1 5 7 7 9 1 5 7 9 3 1 5 7 9 5 1 5 7 9 7 1 5 7 9 9 1 5 9 1 7 1 5 9 1 9 1 5 9 3 3 1 5 9 3 5 1 5 9 3 7 1 5 9 3 9 1 5 9 5 3 1 5 9 5 5 1 5 9 5 7 1 5 9 5 9 1 5 9 7 3 1 5 9 7 5 1 5 9 7 7 1 5 9 7 9 1 5 9 9 3 1 5 9 9 5 1 5 9 9 7 1 5 9 9 9 1 7 1 7 3 1 7 1 7 5 1 7 1 7 7 1 7 1 7 9 1 7 1 9 3 1 7 1 9 5 1 7 1 9 7 1 7 1 9 9 1 7 3 1 9 1 7 3 3 3 1 7 3 3 5 1 7 3 3 7 1 7 3 3 9 1 7 3 5 3 1 7 3 5 5 1 7 3 5 7 1 7 3 5 9 1 7 3 7 3 1 7 3 7 5 1 7 3 7 7 1 7 3 7 9 1 7 3 9 3 1 7 3 9 5 1 7 3 9 7 1 7 3 9 9 1 7 5 1 9 1 7 5 3 3 1 7 5 3 5 1 7 5 3 7 1 7 5 3 9 1 7 5 5 3 1 7 5 5 5 1 7 5 5 7 1 7 5 5 9 1 7 5 7 3 1 7 5 7 5 1 7 5 7 7 1 7 5 7 9 1 7 5 9 3 1 7 5 9 5 1 7 5 9 7 1 7 5 9 9 1 7 7 1 9 1 7 7 3 3 1 7 7 3 5 1 7 7 3 7 1 7 7 3 9 1 7 7 5 3 1 7 7 5 5 1 7 7 5 7 1 7 7 5 9 1 7 7 7 3 1 7 7 7 5 1 7 7 7 7 1 7 7 7 9 1 7 7 9 3 1 7 7 9 5 1 7 7 9 7 1 7 7 9 9 1 7 9 1 9 1 7 9 3 3 1 7 9 3 5 1 7 9 3 7 1 7 9 3 9 1 7 9 5 3 1 7 9 5 5 1 7 9 5 7 1 7 9 5 9 1 7 9 7 3 1 7 9 7 5 1 7 9 7 7 1 7 9 7 9 1 7 9 9 3 1 7 9 9 5 1 7 9 9 7 1 7 9 9 9 1 9 1 9 3 1 9 1 9 5 1 9 1 9 7 1 9 1 9 9 1 9 3 3 3 1 9 3 3 5 1 9 3 3 7 1 9 3 3 9 1 9 3 5 3 1 9 3 5 5 1 9 3 5 7 1 9 3 5 9 1 9 3 7 3 1 9 3 7 5 1 9 3 7 7 1 9 3 7 9 1 9 3 9 3 1 9 3 9 5 1 9 3 9 7 1 9 3 9 9 1 9 5 3 3 1 9 5 3 5 1 9 5 3 7 1 9 5 3 9 1 9 5 5 3 1 9 5 5 5 1 9 5 5 7 1 9 5 5 9 1 9 5 7 3 1 9 5 7 5 1 9 5 7 7 1 9 5 7 9 1 9 5 9 3 1 9 5 9 5 1 9 5 9 7 1 9 5 9 9 1 9 7 3 3 1 9 7 3 5 1 9 7 3 7 1 9 7 3 9 1 9 7 5 3 1 9 7 5 5 1 9 7 5 7 1 9 7 5 9 1 9 7 7 3 1 9 7 7 5 1 9 7 7 7 1 9 7 7 9 1 9 7 9 3 1 9 7 9 5 1 9 7 9 7 1 9 7 9 9 1 9 9 3 3 1 9 9 3 5 1 9 9 3 7 1 9 9 3 9 1 9 9 5 3 1 9 9 5 5 1 9 9 5 7 1 9 9 5 9 1 9 9 7 3 1 9 9 7 5 1 9 9 7 7 1 9 9 7 9 1 9 9 9 3 1 9 9 9 5 1 9 9 9 7 1 9 9 9 9 3 3 3 3 3 5 3 3 3 3 7 3 3 3 3 9 3 3 3 5 5 3 3 3 5 7 3 3 3 5 9 3 3 3 7 5 3 3 3 7 7 3 3 3 7 9 3 3 3 9 5 3 3 3 9 7 3 3 3 9 9 3 3 5 3 5 3 3 5 3 7 3 3 5 3 9 3 3 5 5 5 3 3 5 5 7 3 3 5 5 9 3 3 5 7 5 3 3 5 7 7 3 3 5 7 9 3 3 5 9 5 3 3 5 9 7 3 3 5 9 9 3 3 7 3 5 3 3 7 3 7 3 3 7 3 9 3 3 7 5 5 3 3 7 5 7 3 3 7 5 9 3 3 7 7 5 3 3 7 7 7 3 3 7 7 9 3 3 7 9 5 3 3 7 9 7 3 3 7 9 9 3 3 9 3 5 3 3 9 3 7 3 3 9 3 9 3 3 9 5 5 3 3 9 5 7 3 3 9 5 9 3 3 9 7 5 3 3 9 7 7 3 3 9 7 9 3 3 9 9 5 3 3 9 9 7 3 3 9 9 9 3 5 3 5 5 3 5 3 5 7 3 5 3 5 9 3 5 3 7 5 3 5 3 7 7 3 5 3 7 9 3 5 3 9 5 3 5 3 9 7 3 5 3 9 9 3 5 5 3 7 3 5 5 3 9 3 5 5 5 5 3 5 5 5 7 3 5 5 5 9 3 5 5 7 5 3 5 5 7 7 3 5 5 7 9 3 5 5 9 5 3 5 5 9 7 3 5 5 9 9 3 5 7 3 7 3 5 7 3 9 3 5 7 5 5 3 5 7 5 7 3 5 7 5 9 3 5 7 7 5 3 5 7 7 7 3 5 7 7 9 3 5 7 9 5 3 5 7 9 7 3 5 7 9 9 3 5 9 3 7 3 5 9 3 9 3 5 9 5 5 3 5 9 5 7 3 5 9 5 9 3 5 9 7 5 3 5 9 7 7 3 5 9 7 9 3 5 9 9 5 3 5 9 9 7 3 5 9 9 9 3 7 3 7 5 3 7 3 7 7 3 7 3 7 9 3 7 3 9 5 3 7 3 9 7 3 7 3 9 9 3 7 5 3 9 3 7 5 5 5 3 7 5 5 7 3 7 5 5 9 3 7 5 7 5 3 7 5 7 7 3 7 5 7 9 3 7 5 9 5 3 7 5 9 7 3 7 5 9 9 3 7 7 3 9 3 7 7 5 5 3 7 7 5 7 3 7 7 5 9 3 7 7 7 5 3 7 7 7 7 3 7 7 7 9 3 7 7 9 5 3 7 7 9 7 3 7 7 9 9 3 7 9 3 9 3 7 9 5 5 3 7 9 5 7 3 7 9 5 9 3 7 9 7 5 3 7 9 7 7 3 7 9 7 9 3 7 9 9 5 3 7 9 9 7 3 7 9 9 9 3 9 3 9 5 3 9 3 9 7 3 9 3 9 9 3 9 5 5 5 3 9 5 5 7 3 9 5 5 9 3 9 5 7 5 3 9 5 7 7 3 9 5 7 9 3 9 5 9 5 3 9 5 9 7 3 9 5 9 9 3 9 7 5 5 3 9 7 5 7 3 9 7 5 9 3 9 7 7 5 3 9 7 7 7 3 9 7 7 9 3 9 7 9 5 3 9 7 9 7 3 9 7 9 9 3 9 9 5 5 3 9 9 5 7 3 9 9 5 9 3 9 9 7 5 3 9 9 7 7 3 9 9 7 9 3 9 9 9 5 3 9 9 9 7 3 9 9 9 9 5 5 5 5 5 7 5 5 5 5 9 5 5 5 7 7 5 5 5 7 9 5 5 5 9 7 5 5 5 9 9 5 5 7 5 7 5 5 7 5 9 5 5 7 7 7 5 5 7 7 9 5 5 7 9 7 5 5 7 9 9 5 5 9 5 7 5 5 9 5 9 5 5 9 7 7 5 5 9 7 9 5 5 9 9 7 5 5 9 9 9 5 7 5 7 7 5 7 5 7 9 5 7 5 9 7 5 7 5 9 9 5 7 7 5 9 5 7 7 7 7 5 7 7 7 9 5 7 7 9 7 5 7 7 9 9 5 7 9 5 9 5 7 9 7 7 5 7 9 7 9 5 7 9 9 7 5 7 9 9 9 5 9 5 9 7 5 9 5 9 9 5 9 7 7 7 5 9 7 7 9 5 9 7 9 7 5 9 7 9 9 5 9 9 7 7 5 9 9 7 9 5 9 9 9 7 5 9 9 9 9 7 7 7 7 7 9 7 7 7 9 9 7 7 9 7 9 7 7 9 9 9 7 9 7 9 9 7 9 9 9 9 9

Related posts

This website uses IntenseDebate comments, but they are not currently loaded because either your browser doesn't support JavaScript, or they didn't load fast enough.

{ 1 comment… read it below or add one }

Matt Watson June 27, 2009 at 12:32 am

Hrm, interesting.. a crowbar only takes 2 seconds though :)

Reply

Leave a Comment

Previous post:

Next post: