Most hotel locks these days feature an electronic key system rather than a physical lock and key. This presents an opportunity for the intrepid hacker to gain unauthorized access to hotel rooms. One such hacker, Cody Brocious, gave a demonstration at the Black Hat security conference this year demonstrating a way to read the memory of some of these locks made by the company Onity. His system was large and could only open a small percentage of the locks, and Onity had released a fix for this exploit. However, due to the expensive nature of the fix, it is likely that many hotels still haven't implemented the fix. Matthew Jakubowski, a security researcher for Trustwave, has released a new exploit that packs everything needed to access more than 4 million locks into a dry erase marker, a far more inconspicuous package than that used by Cody.