either a cipher can be trusted or not. using two ciphers is nonsence. also the believ that choosing one of four ciphers will actualy increase the strength or your cryptography is pure nonsence. You will add the weakness of all four cyphers, if one of them has a problem, your software has a problem.
adding more elements to a chain will not make it longer. no matter how strong they are, the propability that one of them is faulty increases. however where a chain is getting longer with more elements and in the real world the lenght of a chain is important, in cryptography it is not. Using more cyphers is not an improvement, no matter whether you pick one of them or you use several of them at the same time. > Isn't it true that a cipher of ciphers with 2 bits used to select one > out of four base ciphers and 128 bit representing the key for the > selected base cipher is stronger than each of the base ciphers. no, it is not true. it is wrong. adding that 2 bits for selecting ciphers make the whole system more fragile, and not stronger. > http://www.counterpane.com/crypto-gram-0303.html: > > "The Doghouse: Random Cryptography Companies > ..... > PMC Ciphers. The theory description is so filled with > pseudo-cryptography that it's funny to read. Hypotheses are presented as > conclusions. Current research is misstated or ignored. The first link is > a technical paper with four references, three of them written before > 1975. Who needs thirty years of cryptographic research when you have > polymorphic cipher theory? > <http://www.ciphers.de/products/polymorphic_cipher_theory.html> > <http://www.ciphers.de/products/bpp_disk.html>" ah, what a nice summary of what you are doing. did you reply to that? is that reply available somewhere? if you replied to schneier, did he reply as well? that would be a very interesting discussion to read. my knowledge of crypto is limited to the basics, but still it is good enough to see the snake oil in your system. However... all crypto people I value admit, that any cypher or system might have a weakness, only no one has found it so far. > Now where's the bug? > To be honest, there is one! sure. And that guy in nigeria really needs my help and will make me rich. > Now let's see if this debate can gain some quality... we both now there are very good places for an honest discussion of cryptology like sci.crypt newsgroup or the cypherpunkt mailing list. what you tried to post your advertising here and hope that noone will see the snake oil in it. so that didn't work. If you want an honest discussion, try it where the experts are and where we can hear both sides. if you can defend your polymorphic cypher in one of these places it might change my ming. Regards, Andreas