Skraken

Skraken is a tool to break the A5/1 ciphering used in GSM. It is a partial rewrite of Kraken that solves its stability issues. The attack is based on a CPU/storage tradeoff that attempts to find the internal state of the A5/1 registers given an observed keystream. The storage component requires a set of 40 rainbow tables that totals ~1.7 TB, although any subset of the tables can be used with a reduced success rate. Using all the tables, the success rate of finding the internal state that generates a GSM burst is around 20%.

For further information, see the README in the Code section.