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US 11,027,554 B2Granted
Supply authentication via timing challenge response
AssigneeHewlett-Packard Development Company, L.P.
InventorsJefferson P. Ward, Stephen D. Panshin
Life of this patent
Estimating the term…
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.
Claims9
A replaceable supply device comprising:
- a print cartridge including printing fluid;
- and
- an electronic device on the print cartridge to facilitate authentication of the replaceable supply device, the electronic device including:
- electrical contacts that communicate data with a host device during operation;
- and
- a microcontroller including:
- a memory including:
- a plurality of calculation counts,
- a base key, and
- a plurality of reference response time windows secured with a digital signature, the plurality of time windows corresponding to the plurality of calculation counts;
- a Central Processing Unit (CPU) in communication with the electrical contacts, the CPU to perform the operations of:
- responding to a timing challenge from the host device via the electrical contacts, and
- generating different session keys from the base key for respective communication sessions;
- and
- a hardware logic circuit in communication with the CPU, the circuit to perform a calculation including the operations of:
- receiving input from the CPU based on the timing challenge received by the CPU from the host device via the electrical contacts, the input including a random seed and one of the session keys, the session key being different for each calculation,
- performing an initial iteration of a mathematical calculation based on the input from the CPU,
- performing a number of additional iterations of the mathematical calculation based on an output of an immediately prior iteration, the number of iterations based on a selected calculation count of the plurality of calculation counts, and
- providing an output from a last of the additional iterations to the CPU, the CPU to prepare a challenge response for transmission to the host device via the electrical contacts within the reference response time window of the plurality of time windows, the reference response time window corresponding to the selected calculation count, for authentication of the replaceable supply device.
16 more elements
Dependencies are inferred from the claim text.