Amanda Walker wrote:
I'm considering DES-EDE (the easy option), Blowfish (also pretty easy), or the DES variant Bruce Schneier describes in Applied Cryptography, 2nd ed. (the one with independent subkeys).
This might be a bad idea. Rumor has it that independent subkeys are eaten alive by related-key attacks (not very practical usually). I think I saw this in a post by Matt Blaze about last November on coderpunks. That post suggested 2 key schedule strategies: 1) planned, like DES, by people who know how a particular schedule affects related-key attacks 2) scrambled, like Turtle & Blowfish, so that key bits all depend on each other in a messy way I mark the margin of my AC book with snippets like this. I don't seem to have kept the post in question. -- Peter Allan peter.allan@aeat.co.uk