Crypto-dongle redux

I think the idea of a standard user configurable crypto-engine is a good one..that way people could choose (and upgrade) algorythms.. sort of like modern DSP based highspeed modems..(It could also have a socket for ROM based firmware cartridges..(RSA,IDEA,etc..) and a magstripe reader and keyboard for key entry..(This would make trading keys easy..) I think this discussion was had before,about a year ago.. Would anyone care to elaborate on it? -Chris.