Andrew Maslar asked: >I'm toying around with various protocols for key exchange, and I wonder, >if an attacker intercepted the result of the following operation: >md5(x) + md5(x + y + z) >Could s/he compute y? [knowing x and z] At 10:57 PM 12/27/98 -0800, Bill Stewart wrote: >If y is a wimpy password, it's pretty easy ("wimpy" being a highly >precise definition, of course :-). [... definition snipped] >So you still, and always, need good passwords, even if you've got >salt to help you. Not always. Many stronger key exchange protocols tolerate wimpy passwords, plain or salted, with minimal risk of network attack. But in *this* protocol, Bill is right. Ordinary use of MD5 or HMAC just doesn't do it. ------------------------- David P. Jablon Integrity Sciences, Inc. [EMAIL PROTECTED] <http://world.std.com/~dpj/>