“At the Black Hat security conference Tuesday evening, a Mozilla software developer and 24-year old security researcher named Cody Brocious plans to present a pair of vulnerabilities he’s discovered in hotel room locks from the manufacturer Onity, whose devices are installed on the doors of between four and five million hotel rooms around the world according to the company’s figures. Using an open-source hardware gadget Brocious built for less than $50, he can insert a plug into that DC port and sometimes, albeit unreliably, open the lock in a matter of seconds.”
Read more about cracking open keycard locks with a homemade $50 device on one brand of hotel security lock.