A secure card system with biometrics capability

The smart card is widely used in E-commerce. We describe the building of a smart card system with embedded biometrics data to strengthen security. First of all, we would like to make the in-card processor do the entire authentication and verification steps so that the card can encapsulate all the critical information, including the biometric data, and performs all the comparison securely inside the card without any data leaking out. However, knowing that the in-card processor has a limited computational power and storage, we would like to seek for a compromise in the time complexity and space complexity for conducting the biometrics comparison and storage entirely by smart card. A domain-specific fixed-point non-integral arithmetic for the card processor is derived as the smart card processor supports only integer arithmetic.