hi, thanx for the replies. one doubt escpecially on this. > >But every algorithm has some >statistical >signature and if you've got enough cipher text you >can compare that >signature with known algorithms to home in on fewer >choices.
can u pls explain how they have statistical signatures,pls- may be using SPN's, i have tried ANSI X9.17 key generation with GOST-it did have a negligably small skew-it makes me wonder what statistical signature they have.The negligable skew is a weakness but not high enough to compramise the security of the key used from the ANSI x9.17 key gen method. pls explain. thank u veru much. Regards Data. --- Mike Rosing <[EMAIL PROTECTED]> wrote: > On Thu, 11 Jul 2002, gfgs pedo wrote: > > > suppose a cryptanalysis only has encrypted > data-how is > > going 2 know which is the encrytion algorithm used > 2 > > encrypt the data ,so that he can effeciently > > cryptanalyse if > > > > 1:>he has large amount of cipher text only > > 2:>has large amount of plain text and > corresponding > > cipher text. > > > > There r so many encryption algorithms,how does he > know > > which algorithm was used? > > Depends on how they got the source. They may know > it's one of 5 > possible choices because of the person who sent (or > received) it. > If it's just found on a disk in a garbage dump with > no connections > to anyone, it's a bit tougher. But every algorithm > has some statistical > signature and if you've got enough cipher text you > can compare that > signature with known algorithms to home in on fewer > choices. > > I'm not sure having the plaintext helps much more, > but you could > use random keys to create several ciphertexts with > known algorithms and > compare the statistics just to see if they compare > better. > > It's definitly challenging :-) > > Patience, persistence, truth, > Dr. mike > > __________________________________________________ Do You Yahoo!? Yahoo! Autos - Get free new car price quotes http://autos.yahoo.com
