The Atmel AT88SA102S is a member of the Atmel CryptoAuthentication family of cost-effective authentication chips designed to securely authenticate an item to which it is attached. It can also be used to exchange session keys with some remote entity so that the system microprocessor can securely encrypt/decrypt data. Each AT88SA102S chip contains a pre-programmed serial number which is guaranteed to be unique. In addition, it has been designed to permit secure personalization so that third parties can build devices containing an OEM secret without concern for the theft of that secret. It is the first small standard product to implement the SHA-256 hash algorithm, which is part of the latest set of recommended algorithms by the US Government. The 256-bit key space renders any exhaustive attacks impossible. The CryptoAuthentication family uses a standard challenge response protocol to simplify programming. The system generates a random number challenge and sends it to the Atmel AT88SA102S chip. The chip hashes that with a 256-bit key using the SHA-256 algorithm to generate a keyed 256-bit response which is sent back to the system.