The ATSHA204A is a Secure Hash Algorithm (SHA)-based CryptoAuthentication crypto element. It integrates the SHA-256 hash algorithm with a 4.5Kb EEPROM and provides robust hardware authentication using secure key/data storage. By offloading key storage and algorithm execution from the microcontroller, it significantly reduces system cost and complexity.
The 4.5Kb EEPROM is divided into 16 slots, which can be used for storage of keys, miscellaneous read/write, read-only, password or secret data, and consumption tracking. Access to the various sections of memory can be restricted in a variety of ways and then the configuration locked to prevent changes.