by Michael Kassner...
For all intents and purposes most everyone including the GSMA—an organization representing most of the mobile phone operators—considered and still considers GSM very secure. In reality A5/1, the technology used to encrypt GSM communications has been vulnerable for at least a decade. The sense of security seems to be based on the fact that the original attack venues require a great deal of computing power, time, and therefore money to accomplish the crack. So an organization would have to be particularly motivated to even want to crack GSM traffic. Care to guess who has enough motivation?
It appears that researchers David Hulton and Steve Miller have recently developed techniques to greatly reduce the time and required computing power needed to crack A5/1 encryption. The two researchers have even patented their work personally. The efficient modifications of the original crack open all sorts of doors making it easier for both black and white hat types to decode GSM conversations. (more)
