Consumable authentication protocol and system

摘要

This invention concerns a consumable authentication protocol for validating the existence of an untrusted authentication chip, as well as ensuring that the Authentication Chip lasts only as long as the consumable. In a further aspect it concerns a consumable authentication system for the protocol. In this invention we are concerned not only with validating that an authentication chip is present, but writes and reads of the authentication chip's memory space must be authenticated as well. A random number and an encrypted version of it are produced in a trusted authentication chip and passed to an untrusted authentication chip. The untrusted chip encrypts the random number to determine whether it gets the same result as the trusted chip. If so then it re-encrypts the random number together with a data message using a second key and sends it back with the data message. The trusted chip then encrypts the data message and random number with the second key for comparison.