BlackHat 2012 proved once again to be an interesting conference full of the latest security research, training and hacks. One interesting presentation proved how insecure hotel locks are, specifically the ones utilizing the magnetic card keys. Hacker Cody Brocious used nothing more than a simple Arduino to read digital data and replay it. More specifically, a DC power port on the bottom of Onity locks allows for recharging the on-board battery and configuring a hotel specific code into the door. Using the Arduino, Brocious plugged into the DC port, read the 32bit hotel specific code and simply played it back which has the simple effect of ... unlocking the door. A full technical write-up is available at the hacker's website.