On Mon, 2010-08-02 at 11:02 -0400, Bill Squier wrote: > "...In his presentation at the Black Hat Conference, German GSM expert > Karsten Nohl presented a tool he calls Kraken, which he claims can crack the > A5/1 encryption used for cell phone calls within seconds." > > http://www.h-online.com/security/news/item/Quickly-decrypting-cell-phone-calls-1048850.html >
A quick list of bullet points on what is new here: * 2TB (1.7 compressed) of GSM A5/1 rainbow tables have been created * These tables leverage the fact that A5/1 suffers from "keyspace convergence". After the initial 100 warm-up clockings, only 16% of the keyspace remains valid. * The rainbow tables only sample the converged space, such samples are equivalent to sampling all of the on average 13 initial states that converge to the sampled point. * Efficient ATI GPU code has been written, that allowed us to compute the tables in 8 "GPU months", and were effectively completed in just 4 weeks, using 4 computers and 850kWh of power. * Depending on the random access speed of the storage medium, 64 bits keys for a particular conversation can be cracked in minutes or seconds. * We have made all software and the tables freely available. Frank A. Stevenson --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [email protected]
