Authentication of a Consumable

Abstract

A method authenticating a consumable is disclosed. The consumable includes a first integrated circuit operative to receive data and return the data encrypted. The method receives a random number from a trusted second integrated circuit. The random number is communicated to the first integrated circuit, and in response a first message containing the random number encrypted by the first integrated circuit is received from the first integrated circuit. Also, a second message containing the random number encrypted by the trusted integrated circuit is received from the trusted second integrated circuit. By comparing the first and second messages it is determined that the consumable is authentic when the first and second messages are the same.

1 . A method authenticating a consumable, the consumable including a first integrated circuit operative to receive data and return the data encrypted, the method comprising the steps of:
 receiving a random number from a trusted second integrated circuit;   communicating the random number to the first integrated circuit;   receiving from the first integrated circuit a first message containing the random number encrypted by the first integrated circuit;   receiving from the trusted second integrated circuit a second message containing the random number encrypted by the trusted integrated circuit;   comparing the first and second messages, the consumable being authentic when the first and second messages are the same.   
   
   
       2 . The method according to  claim 1  wherein communication to and from the first and second integrated circuits are insecure. 
   
   
       3 . The method according to  claim 1  further comprising an initial step of:
 requesting the random number from the trusted first integrated circuit.   
   
   
       4 . The method according to  claim 1  further comprising the step of:
 communicating the random number to the trusted second integrated circuit when communicating the random number to the first integrated circuit.   
   
   
       5 . The method according to  claim 1  wherein different instances of the trusted second integrated circuit contain random number generators seeded with different initial values. 
   
   
       6 . The method according to  claim 1  wherein encryption uses a key stored in the respective integrated circuits. 
   
   
       7 . The method according to  claim 6  wherein the key is secret.