GSM Security Broken

Researchers from the Technion Institute of Technology in Haifa, Israel have succeeded in cracking the popular GSM cellular phone network encryption code. The researchers presented their findings at the recent Crypto Conference in Santa Barbara , California . The findings were greeted with shock and widespread interest on the part of the 450 conference participants, many of whom are world leaders in encryption research and encryption industry.

The researchers, Prof. Eli Biham and doctoral student Elad Barkan, and Nathan Keller, discovered a basic flaw in the network's encryption system, and using this were able to develop a method for cracking the encryption system. "Elad discovered a serious flaw in the network's security system," explains Prof. Biham. "He found that the GSM network does not work in the proper order: First, it inflates the information passing through it in order to correct for interference and noise and only then encrypts it."

In the wake of this discovery, the three Technion researchers developed a method that enables cracking the GSM encryption system at the initial ringing stage, even before the call begins, and later on, listening in on the call. With the aid of a special device that can also broadcast, it is possible to steal calls and even to impersonate phone owners, even in the middle of an ongoing call. Recently, a new and modern encryption system was chosen as a response to previous attacks on existing encryption system. But Technion researchers also succeeded in overcoming this improvement.

Prof. Biham explains that encryption ciphers were kept absolutely secret until 1999 when a researcher called Marc Briceno succeeded to reverse engineer their algorithms. "Since then many attempts have been made to crack them, but these attempts required knowing the call's content during its initial minutes in order to decrypt its continuation, and afterwards, to decrypt additional calls. Since there was no way of knowing call content, these attempts never reached a practical stage. Our research shows the existence of the possibility to crack the codes without knowing anything about call content," he notes.

A copy of the research was sent to GSM authorities in order to correct the problem, and the method is being patented so that in future it can be used by the law enforcement agencies."

Posted to the site on 4th September 2003