SCALPS: Smart card for limited payment systems

Secure money-transfer cards continue to find acceptance in commerce. Currently, three main types of these cards coexist: magnetic stripe, mass memory, and smart. We describe another approach: merging the processor and coprocessor on a small chip dedicated to public-key cryptography. We added parts needed to obtain a low-cost smart card compatible with the ISO 7816-3 standard. By developing the processor for specific applications, we drastically reduced the complexity without affecting the chip´s usefulness. To prove the feasibility of such a chip, we built one for use in a payment application with prepaid tokens