This document discusses and compares two public key cryptosystems - RSA and Elliptic Curve Cryptography (ECC) - for use in smart cards. It finds that ECC provides equivalent security to RSA but with significantly smaller key sizes, making it more efficient and suitable for smart cards with limited storage and processing capabilities. The document outlines the principles, key generation algorithms, and encryption/signature schemes for both RSA and ECC, including specific algorithms like Menezes-Vanstone and Nyberg-Rueppel. It analyzes the security level, efficiency, and space requirements of RSA and ECC, finding that ECC requires keys 10 times smaller than RSA for the same security level and its operations are an order of magnitude faster.