What are the dangers of taking a small block of data - say upto 1K in size, then producing many files, each being the same data encrypted by other keys? i.e.: Plain data: 1K in size or smaller File 1: Data encrypted with Key1 File 2: Data encrypted with Key2 File 3: Data encrypted with Key3 File 4: Data encrypted with Key4 File 5: Data encrypted with Key5 File 6: Data encrypted with Key6 File 8: Data encrypted with Key8 .... File N: Data encrypted with KeyN A known plaintext attack won't help you to break the keys unless you have one of the eight keys, but will having many keys that encrypt the same data significanltly weaken the security of that tiny chunk of data? And no, I don't mean, there's N keys so the odds of brute forcing the data is now N times easier. Assume we're using 128 bit Blowfish/Idea or better, and discarding weak keys. Are there any differential or other cryptanalysis methods to use the eight resulting cyphertexts to get at the data other than brute forcing it if you don't know any of the keys? What if instead of using a private key cypher, we used a public key cypher? Would that make any difference in attack methods? The data won't contain any text, or identifiers (i.e "GIF89" in GIF files, "MZ" in wintel executables, etc...) known or guessable to the attacker... =====================================Kaos=Keraunos=Kybernetos============== .+.^.+.| Ray Arachelian |Prying open my 3rd eye. So good to see |./|\. ..\|/..|sunder@sundernet.com|you once again. I thought you were |/\|/\ <--*-->| ------------------ |hiding, and you thought that I had run |\/|\/ ../|\..| "A toast to Odin, |away chasing the tail of dogma. I opened|.\|/. .+.v.+.|God of screwdrivers"|my eye and there we were.... |..... ======================= http://www.sundernet.com ==========================