Matthew J Ghio says:
Karl Barrus wrote:
Well, you do have to be careful: a large number of keys doesn't mean a cipher is hard to break, there may be a faster method than brute force.
Quite true! However, as I pointed out, I tried very hard to eliminate all such possibilities that would allow simplifying the key search process.
Matt, pardon my saying this, but you sound rather foolish. Did you, for instance, deliberately make any attempt to prevent differential cryptanalysis? linear cryptanalysis? Related key attacks? Can you define any of these? If the answer to any of these is "no" then you probably aren't in a position to try to design a cryptosystem. Frankly, I understand all the attacks and I wouldn't trust anything of my own design -- maybe after letting Biham have a crack at it for a couple of months I'd feel that I hadn't done anything obviously wrong and after a year or two of seeing lots of people try to attack it and fail I'd consider using it -- if there weren't other systems around that I was more confident in. Given how easy it is to code up an IDEA or mixed IDEA/DES multround beast, I see no real advantage to trying to build my own, and lots of disadvantages. Perry