Validation protocol and system
AssigneeSilverbrook Research Pty Ltd
InventorsSimon Robert Walmsley, Paul Lapstun
Life of this patent
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Abstract
This invention concerns a validation protocol for determining whether an untrusted authentication chip is valid, or not. The protocol may be used to determine the physical presence of a valid authentication chip and from that determine whether a consumable containing the chip is valid. In another aspect the invention also concerns a system for validating the chip. The invention involves generating a random number in a trusted authentication chip, then applying a keyed one way function to the random number in both the trusted authentication chip and an untrusted authentication chip and comparing the outcomes. A match indicates that the untrusted chip is valid.
Claims10
A validation protocol performed in a system for determining whether an untrusted authentication chip in communication with the system is valid, or not, including the steps of:
- generating a random number in a trusted authentication chip in communication with the system;
- applying, in the trusted authentication chip, a keyed one way function to the random number using a first secret key from the trusted authentication chip to produce a first encrypted outcome;
- applying, in the untrusted authentication chip, a keyed one way function to the random number using a second secret key from the untrusted authentication chip to produce a second encrypted outcome;
- comparing, using the system, the first encrypted outcome and the second encrypted outcome, without knowledge of the first and second secret keys, and in the event of a match considering the untrusted chip to be valid;
- otherwise considering the untrusted chip to be invalid.
A validation system for determining whether an untrusted authentication is valid, or not, where the system comprises:
- a random number generator to generate a random number;
- a trusted authentication chip, the trusted authentication chip including a keyed one-way function and a first secret key for the one-way function, the trusted authentication chip applying the keyed one way function to the random number using the first secret key to produce a first encrypted outcome;
- an untrusted authentication chip, the untrusted authentication chip including the keyed one way function and a second secret key, the untrusted authentication chip applying the keyed one way function to the random number using the second secret key to produce a second encrypted outcome;
- and
- comparison means to compare the first encrypted outcome and the second encrypted outcome, without knowledge of the first and second secret keys;
- whereby, in the event of a match between the outcomes from the trusted chip and the untrusted chip, the untrusted chip is considered to be valid.
Dependencies are inferred from the claim text.