To validate the authenticity of a consumable or replaceable item (a client) when it is connected to a system (a host), there must be some secret information stored in both the client and the host. The CryptoMemory or CryptoRF chips provide a secure location to store this secret data in the client, while the CryptoCompanion chip stores the information in the host. CryptoCompanion provides plug-and-play host-side cryptographic security for embedded systems. This plug-and-play convenience means that designers do not have to design or test the cryptographic algorithms. The companion chip implements the necessary algorithms and the entire protocol completely in hardware. The chip is fully tested and guaranteed to work with all CryptoMemory and CryptoRF chips.