The DS28C22 is a DeepCover® secure authenticator with I²C interface that uses the SHA-256 algorithm for bidirectional authentication. Additional features, including a 3Kb user EEPROM array, multiple memory protection methods and advanced physical security, combine to provide the ultimate in cost-effective IP protection, clone prevention, and authentication. This document describes operating principles of the device, its special features, and its typical application environment.
With a size of 256 bits each for the secret, challenge, and MAC, SHA-256 is a significant improvement over older SHA-1 authentication. This article presented a modern, secure authentication system that matches a host system (host controller with SHA-256 secure coprocessor) with a sensor/peripheral module (the SHA-256 secure authenticator). SHA-256 security has never been easier.