The security of GSM phone calls dropped again late Monday with word that the standard's second, more guarded encryption standard has been broken. Following a first crack of the simpler standard, researchers at the Weizmann Institute of Science say they have cracked the A5/3 security cipher (nicknamed Kasumi) by using what's known as a "sandwich" attack. The group accomplished its goal by creating a distinguishing trait for the key and using just four related keys to determine the key for Kasumi itself.
