Sharp Wizard as a Crypto Dongle?

I had the same idea, only with an HP48SX (I work for HP); the 48 is a little pricier, but cheaper than say the 95LX or similar pocket PC's. (I got as far as a DES implementation in user RPL -- I "ported" the Ferguson DES in a day or so; I haven't gotten around to slogging through converting it into system RPL or machine code). Progammable consumer products would be pretty good as *prototypes*, but not good enough for "production" use in the presence of a determined attacker due to lack of tamper-resistance. [my apologies if this came up before; I'm new to the list]. - Bill