Cloning of a GSM mobile phone

Author: Niels Jørgensen.
The top of my webpage here at Roskilde University.
Last update to the present page: May 20th, 2018.

This web page describes my research into the attack conducted in 1998 by members of the German hacker group, Chaos Computer Club, on GSM's authentification algorithm, the infamous comp128. The successful attack enabled the CCC members to "clone" a GSM mobile phone.

The Chaos Computer Club's attack, taking place in April 1998, had been described in theory by three Californian cryptologists (Briceno, Wagner and Goldberg) earlier in the same month. The cloning attack obtains the secret key of the phone's SIM-card. One can then copy the key onto another SIM-card, and make phone calls with the identify of the owner of the first SIM-card. In particular, that owner will get billed for the calls. The CCC members cloned a SIM-card held by a Spiegel-journalist who subsequently wrote about the attack in the magazine on April 27.

I would like to know the answers to questions such as: