Experimenting with Electronic Commerce on the PalmPilot

This paper describes our experience with implementing an electronic payment system for the PalmPilot. Although Palm OS lacks support for many desired security features, we are able to build a system suitable for small payments. We discuss the advantages and disadvantages of using a PDA to make secure payments as opposed to using a smartcard or a desktop PC. In addition, we describe the engineering of PDA-PayWord, our implementation of a commerce protocol that takes advantage of both elliptic curve and RSA public key cryptography to support payments efficiently on PDAs with limited processing capability.