> No. Unless you know something I don't, This is voodoo. To do it once might > add something, but to do it multiple times, with strongly correlated inputs > seems potentially dangerous. Especially since you are XORing them. Does > anyone elsewhere in the cryptographic world do something like this?
Yes, there is one other thing that does this. freebsd md5 crypt -- It back-feeds inner state and outer state in loop and data-dependent ways; it is a true miracle. Noone should do that. These Cryptographic primitives are only strongd when they are used exactly as intended.