Integrated circuit cards or smart cards are now well-known. Applications such as electronic purses (cash units stored in cards), subscriber identification cards used in cellular telephone or access keys for pay-TV and information highways emerge in many places with millions of users. More services are required by applications providers and card holders. Mainly, new integrated circuit cards evolve towards non-predefined multi-purpose, open and multi-user applications. Today, operating systems implemented into integrated circuit cards cannot respond to these new trends. They have evolved ple operating systems defining an hardware abstraction level up to file management systems or database management systems where the card behaviour was defined once at the manufacturing level or by the card issuer. The needs for open and flexible card life cycle enabling to accommodate executable code loaded by different service providers require a new generation of smart cards. Operating systems based on...