Quote from: n2liquid on June 18, 2011, 11:27:09 AM

So the USB Wallets should be easily expansible to support changes in the Bitcoin cryptosystem. FPGA's, I think, are generally better suited for that than a microprocessor like Arduino/Atmel's AVR (wish I'm not sure can even handle signing a transaction in, like, less than a minute), or even some powerful ARM processor.

I think an FPGA is something really worth having in a USB Wallet, but that's something we can all discuss, try out, etc.

The link I posted above says that the atmega8 (an 8-bit low-end microcontroller) can do

Quote

On-token private key operations (ECDSA Sign) with acceptable speed (~2seconds/sign for prime192v1 NIST curve)

Also consider that there are faster drop-in replacement like the atmega328 (cost < $3)