Consumable authentication protocol and system
First Claim
1. A consumable authentication protocol for validating the authenticity of an untrusted authentication chip, the protocol includes the steps of:
- generating a random number and applying a keyed one-way function to the random number using a first secret key to produce a first outcome, in a trusted authentication chip;
passing the random number and the first outcome to the untrusted authentication chip;
applying the keyed one-way function to the random number using the first secret key to produce a second outcome, in the untrusted authentication chip, and then comparing the first and second outcomes;
in the event that the first and second outcomes match, applying the keyed one-way function to the random number together with a data message read from the untrusted chip using a second secret key to produce a third outcome, in the untrusted chip;
passing the third outcome together with the data message to the trusted chip;
applying the keyed one-way function to the random number together with a data message read from the untrusted chip using the second secret key to produce a fourth outcome, in the trusted chip;
comparing the third and fourth outcomes in the trusted chip, and in the event of a match, considering the untrusted chip and the data message to be valid;
otherwise considering the untrusted chip and the data message to be invalid.
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Accused Products
Abstract
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.
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Citations
23 Claims
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1. A consumable authentication protocol for validating the authenticity of an untrusted authentication chip, the protocol includes the steps of:
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generating a random number and applying a keyed one-way function to the random number using a first secret key to produce a first outcome, in a trusted authentication chip;
passing the random number and the first outcome to the untrusted authentication chip;
applying the keyed one-way function to the random number using the first secret key to produce a second outcome, in the untrusted authentication chip, and then comparing the first and second outcomes;
in the event that the first and second outcomes match, applying the keyed one-way function to the random number together with a data message read from the untrusted chip using a second secret key to produce a third outcome, in the untrusted chip;
passing the third outcome together with the data message to the trusted chip;
applying the keyed one-way function to the random number together with a data message read from the untrusted chip using the second secret key to produce a fourth outcome, in the trusted chip;
comparing the third and fourth outcomes in the trusted chip, and in the event of a match, considering the untrusted chip and the data message to be valid;
otherwise considering the untrusted chip and the data message to be invalid. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification