This open source software allows the 'cracking' of A5/1 keys used to encrypt GSM 2G calls and SMS.
The cracking utility Kraken, developed by Frank A. Stevenson, is written in C++/python and runs on AMD GPUs or CPUs.
Kraken leverages rainbow tables that were computed as a community effort.

Mailing list

A public mailing list for announcements and discussion can be found here .
You may also file bugs and support requests through the issue tracker if they are of little relevance to the majority of the mailing list subscribers.


The (read only) Kraken git can be fetched with

git clone git://

Rainbow tables

Decryption is achieved with rainbow tables , which can be downloaded through BitTorrent

Related projects

The A5/1 decryption was originally meant to be used with Airprobe), which allows interfacing with the radio waves with
the help of gnuradio.

Airprobe has, for most users, since been replaced by the cheaper Osmocom phones

Further reading on A5/1 Cryptoanalysis

Updated by Karsten almost 4 years ago ยท 16 revisions