Methods and Systems for Determining the Authenticity of a Component

1 . A method of authenticating a first supply item in an imaging device, wherein the first supply item is designated as a prover supply item, and a second supply item installed in the imaging device is designated as a verifier supply item, the method comprising:

receiving, by the verifier supply item, a challenge response from the prover supply item, and

determining, by the verifier supply item, a status of the challenge response, the status being verified or unverified, wherein when the verifier supply item determines that the received challenge response is a correct output of an algorithm when challenge data is input to the algorithm, the status is determined as verified.

2 . The method of claim 1 , further comprising:

processing, by the prover supply item, check data, said check data being from a controller of the imaging device, and

receiving, by the controller, the processed check data from the prover supply item.

3 . The method of claim 2 , further comprising:

sending, by the controller, check data to the prover supply item.

4 . The method of claim 2 , further comprising:

determining, by the controller, a status of the received processed check data, the status being verified or unverified.

5 . The method of claim 1 , further comprising:

selecting the algorithm from an available set of algorithms.

6 . The method of claim 5 , wherein all algorithms in the available set of algorithms are algorithms for which the verifier supply item is trusted by the controller.

7 . The method of claim 6 , wherein all algorithms in the available set of algorithms are algorithms which are designated as required by the controller.

8 . The method of claim 6 , wherein selecting comprises,

when the available set of algorithms includes one or more algorithms for which the prover supply item is untrusted by the controller, selecting the algorithm from the one or more algorithms for which the prover supply item is untrusted by the controller.

9 . The method of claim 8 , wherein selecting further comprises:

when the available set of algorithms does not include any algorithms for which the prover supply item is untrusted by the controller:

adding, to the available set, any algorithms for which (i) the verifier supply item is trusted by the controller and (ii) are supported by the prover supply item and selecting the algorithm from the available set at random.

10 . The method of claim 1 , further comprising:

selecting the second supply item from a set of supply items, the set including all supply items installed in the imaging device which are trusted by the controller for at least one algorithm.

11 . The method of claim 1 , further comprising:

when at least one supply item installed in the imaging device is untrusted by the controller for at least one algorithm, selecting the first supply item from a set of supply items, the set including all supply items which installed in the imaging device which are untrusted by the controller for at least one algorithm, excluding the second supply item.

12 . The method of claim 11 , wherein selecting the first supply item from the set of supply items comprises selecting the supply item with the most algorithms for which the supply item is untrusted by the controller.

13 . The method of claim 1 , further comprising:

when all supply items installed in the imaging device are trusted by the controller for all algorithms, selecting the first supply item at random from a set of supply items including all supply items installed in the imaging device except the second supply item.

14 . The method of claim 1 , further comprising:

redesignating the first supply item as the verifier supply item,

redesignating the second supply item as the prover supply item, and

receiving, by the verifier supply item, a further challenge response from the prover supply item, and

determining, by the verifier supply item, a status of the further challenge response, the status being verified or unverified, wherein when the verifier supply item determines that the received further challenge response is a correct output of a further algorithm when further challenge data is input to the further algorithm, the status of the further challenge response is determined as verified.

15 . A supply item configured to perform as a verifier supply item when installed in an imaging device, the verifier supply item being configured to receive a challenge response from a prover supply item installed in the imaging device, and determine, a status of the challenge response, the status being verified or unverified, wherein when the verifier supply item determines that the received challenge response is a correct output of an algorithm when challenge data is input to the algorithm, the status is determined as verified.

16 . A supply item according to claim 15 , wherein the verifier supply item is configured to select the algorithm from an available set of algorithms.

17 . A supply item according to claim 16 , wherein verifier supply item is configured to send an indication of the algorithm to the prover supply item.

18 . A supply item according to claim 15 , wherein the verifier supply item is configured to send an indication of the algorithm to a controller of the imaging device.

19 . A supply item according to claim 15 , wherein the verifier supply item is configured to send the status of the challenge response to a controller of the imaging device.

20 . A supply item according to claim 15 , configured to perform as the verifier supply item when trigger data is received by the supply item from a controller of the imaging device.