On Tue, Jan 04, 2011 at 12:57:28PM +0200, Omar Atia wrote: > Dears, > > Why you are creating rainbow tables ? I have read what is in Airprobe > sniffing ways it is missing how do you decrypt the cipher text with Kc ? do > you have this stage or you are only creating these tables ?
The tables had been finished in last years summer and they work as intended. > > How can I start the study ? wikipedia: Rainbow Table http://reflextor.com/trac/a51/wiki/BackclockA51 > > Are you writing all possibilities on a disk ? of the 2^64 keyspace, 2^53 data points are computed and 2^38 are stored on disk. The 2^53 data points that are effectively contained in the tables map about 2^56.5 data points of the keyspace. Since each chain has an average length of 2^15 the number of data points stored is 2^38, even though the table contains 2^53 data points. 2^56.5 is enough because a single gsm burst lets you do 51 independent lookups in the tables (Time Memory Data Tradeoff). 2^53 table values cover 2^56.5 of the keyspace, because in gsm A5/1 is clocked 100 times before the keystream is used to encrypt the plaintext stream and the A5/1 cipher by its structure converges to a smaller subset of the state space when it is clocked. Meaning that of the 2^64 possible states, 2^3 are unreachable after 100 clocks and thus can be ignored. _______________________________________________ A51 mailing list A51@lists.reflextor.com http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
