The Atmel AT88SC0104CA member of the Atmel CryptoMemory? family is a high-performance secure memory providing 1-Kbit of user memory with advanced security and cryptographic features built in. The user memory is divided into four 32-byte zones， each of which may be individually set with different security access rights or effectively combined together to provide space for one to four data files. The AT88SC0104CA features an enhanced command set that allows direct communication with microcontroller hardware 2-wire interface thereby allowing for faster firmware development with reduced code space requirements. 1.1 Smart Card Applications The AT88SC0104CA provides high security， low cost， and ease of implementation without the need for a microprocessor operating system. The embedded cryptographic engine provides for dynamic， symmetric-mutual authentication between the device and host， as well as performing stream encryption for all data and passwords exchanged between the device and host. Up to four unique key sets may be used for these operations. The AT88SC0104CA offers the ability to communicate with virtually any smart card reader using the asynchronous T = 0 protocol （Gemplus Patent） defined in ISO 7816-3.