On Sat, 2010-01-09 at 23:39 +0100, sascha wrote: > Another question is whether it is possible to convert an illegal state > that produces the correct keystream to a legal state > that produces the same keystream. When i generated some chains with > a simple increment function generating the start values i got 92% chain > merges in a 10M chains table which suggests that those states that > produce the same keystream are only a few bit flips apart.
I am not sure if a simple bit flip will do it, but perhaps it is possible by applying single or few clockings of some direction to some of the LFSRs, so you get a "legal" state, but yet produce the same output. Unfortunately when I found my false positives, I had thrown away the original keys, and had no basis to compare the false positive with the correct state. We should keep this in mind when we start testing the lookup code at a bigger scale: to keep the correct keys for reference and helping us understand better what the situation is with the false positives. f _______________________________________________ A51 mailing list A51@lists.reflextor.com http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
