[LINK] Australia, and GSM A5/1/2/3 protocols

stephen at melbpc.org.au stephen at melbpc.org.au
Sun Jan 3 17:36:16 AEDT 2010

GSM encryption is now effectively broken    

by David Heath Friday, 01 January 2010  

At the 26th Chaos Communication Congress (26C3) last week, Karsten Nohl 
offered new insights and methods for cracking GSM encryption.

Security researchers have long considered GSM security to be weak and 
there have been many projects aimed at exposing a variety of these 
security weaknesses.  

There are four levels of encryption available for GSM, discussed in 
detail here:  http://www.itwire.com/content/view/16824/1154/

Many countries were not given access to any form of encryption .. and 
only the most friendly (mainly Western Europe and USA) were given access 
to the strongest (called A5/1).  

Australia was not considered a favoured country and was only permitted to 
implement the fully broken A5/2 protocols.  

A Wikipedia article gives good detail of the history of attacks on A5/1.


There is an interesting report from 1994 of the political in-fighting 
which led to the selection of the knowingly weak French solution over the 
strong objections of the Germans who (at the time) shared a border with a 
number of communist countries and would have preferred very strong 


A recently reported project to create rainbow tables for GSM decryption 
has reached its end – the tables are available and at just 2TB, are 
smaller than expected.  


Karsten Nohl's presentation at 26C3 outlines the work completed thus far 
and also describes early efforts to fully crack the supposedly more 
secure A5/3 protocol.  


Much of the project management is being handled through the Trac site 
where news, source code and other resources are available. 

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