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US 11,691,429 B2Granted
Supply authentication via timing challenge response
AssigneeHewlett-Packard Development Company, L.P.
InventorsJefferson P. Ward, Stephen D. Panshin
Life of this patent
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Abstract
In an example implementation, a print supply cartridge comprises a microcontroller to receive a timing challenge and enable authentication of the cartridge by providing a challenge response. The challenge response is provided in a challenge response time that falls within an expected time window.
Claims20
A device to facilitate authentication of a replaceable supply device, the device separate from a host, the device comprising:
- electrical contacts that communicate data with the host during operation, the electrical contacts to obtain a timing challenge from the host;
- at least one memory having stored thereon a base key, a challenge response time, and a calculation count for the challenge response time;
- processor circuitry to execute first instructions to generate a plurality of session keys based on the base key, respective session keys specific to particular communication exchanges between the CPU and the host;
- and
- a dedicated hardware logic circuit to execute second instructions to:
- perform an initial calculation based on a mathematical function with a random seed and one of the plurality of sessions keys as inputs;
- perform a number of additional calculations with the output of a prior calculation as input, the number of additional calculations based on the calculation count;
- and
- determine a challenge response based on an output of a last of the additional calculations, within the challenge response time;
- and
- the processor circuitry to cause communication of the challenge response to the host via the electrical contacts.
8 more elements
A print cartridge comprising:
- a print material supply chamber;
- at least one memory to store a plurality of calculation counts and a plurality of time windows corresponding to the plurality of calculation counts;
- and
- logic circuitry to execute instructions to:
- perform a first challenge calculation of a plurality of challenge calculations, the first challenge calculation to be performed with input parameters to produce an output, the input parameters including a session key that is different for each time challenge calculation session,
- repeatedly perform a number of subsequent challenge calculations, respective subsequent challenge calculations using an output of a preceding calculation, the number of subsequent calculations based on one of the plurality of calculation counts and affecting the response time, and
- use an output of a last challenge calculation for a timing response value, the plurality of challenge calculations to be performed within one of the plurality of time windows that corresponds to the one of the plurality of calculation counts;
- and
- provide the timing response value within the time window to authenticate the print cartridge.
6 more elements
A print cartridge comprising:
- a print material supply chamber;
- at least one memory to store at least one time window and at least one calculation count, respective ones of the at least one calculation count corresponding to respective ones of the at least one time window;
- and
- logic circuitry to execute instructions to:
- perform a first challenge calculation of a plurality of challenge calculations, the first challenge calculation to be performed with input parameters to produce an output, the input parameters including a session key that is different for each time challenge calculation session,
- repeatedly perform a number of subsequent challenge calculations, respective subsequent challenge calculations using an output of a preceding calculation, the number of subsequent calculations based on one of the at least one calculation count and affecting the response time, and
- use an output of a last challenge calculation for a timing response value, the plurality of challenge calculations to be performed within one of the at least one time window that corresponds to the one of the at least one calculation count;
- and
- provide the timing response value within the time window to authenticate the print cartridge.
6 more elements
A device to facilitate authentication of a replaceable print cartridge supply device, the print cartridge supply device including electrical contacts to obtain a timing challenge from a host, the device separate from the host, the device comprising:
- dedicated hardware logic circuitry designed to run a timing challenge calculation;
- at least one memory having stored thereon:
- a base key;
- instructions for the device to perform cryptographic operations;
- a calculation count to define a number of calculations of the timing challenge calculation;
- and
- a challenge response time within which the dedicated hardware logic circuitry is to output the response value of the timing challenge calculation;
- and
- processor circuitry to execute the instructions to:
- generate a plurality of session keys based on the base key, respective session keys specific to particular communication exchanges between the processor circuitry and the host;
- receive the timing challenge and initiate the dedicated hardware logic circuitry to run the timing challenge calculation;
- and
- cause communication of the timing challenge response value, as calculated by the dedicated hardware logic circuitry, to the host via the electrical contacts;
- wherein the dedicated hardware logic is designed and fabricated to:
- perform an initial calculation based on a random seed and one of the plurality of sessions keys as inputs;
- perform a number of additional calculations with the output of a prior calculation as input, the number of additional calculations based on the calculation count;
- and
- within the response time, calculate and output the timing challenge response value from a last of the additional calculations.
15 more elements
Dependencies are inferred from the claim text.