Among the technologies cracked by security researchers at the show were hotel room locks, iris scanners, Google Bouncer, point of sale terminals, and near-field communication technology.

Those attending the conference and staying in hotel rooms must have found unsettling a presentation by Mozilla software developer Cody Brocious. He demonstrated a homebrewed device made for $50 that .

The gadget is similar to what hotels use to program locks to accept master key cards. However, the device works only on locks made by Onity, and it works about 33 percent of the time. On the other hand, there are from 4 to 5 million hotel rooms worldwide that have the locks to experiment on.

A highly secure biometric form of identity authentication was also undermined at Black Hat. Spanish researchers showed how they could create a of a person's eye. In tests against a top commercial recognition system, the iris scanner was fooled 80 percent of the time, according to the team from Universidad Autonoma de Madrid.