Apparatus for validating the presence of an authorized accessory
AssigneeSilverbrook Research Pty Ltd
InventorKia Silverbrook
Life of this patent
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Abstract
An apparatus for validating the presence of an authorized accessory of the apparatus includes an integrated circuit which stores a secret key K, is configured to define a random number generator which returns R and is configured to apply a function F[R] to return FK[R], based on the secret key K. The apparatus includes a control system which is configured to request FK[R] from the integrated circuit and from a further integrated circuit positioned on the accessory and to compare FK[R] from both the integrated circuits.
Claims4
An apparatus for validating the presence of an authorized consumable unit of a printing device, the consumable unit having a first authentication integrated circuit that is configured to store a secret key KA and data on a printing consumable of the consumable unit, the apparatus comprising:
- a second integrated circuit which stores a public key KT and is configured to hold a random number function which returns random number R, the second integrated circuit being configured to apply a function F[R] to return FKT[R], based on the public key KT, and the first integrated circuit being configured to apply a function D[FKT[R]] to return DKA[FKT[R]], based on the secret key KA;
- and
- a control system which is configured to request FKT[R] from the second integrated circuit, to request DKA[FKT[R]] from the first integrated circuit to obtain RA, and to compare R return by the second integrated circuit with RA returned by the first integrated circuit.
A method of validating the presence of an authorized consumable unit of a printing device, the method comprising the steps of:
- storing a secret key, KT, in an integrated circuit of the printing device and storing a secret key, KA, in an integrated circuit of the consumable unit which also stores data on a printing consumable of the consumable unit;
- generating a random number R with the integrated circuit of the printing device;
- applying a function F to R using KT at the integrated circuit of the printing device to return FK and applying a function D to FK using KA at the integrated circuit of the consumable unit to return RA;
- and
- comparing R from the integrated circuit of the device with RA from the integrated circuit of the consumable unit.
Dependencies are inferred from the claim text.