Method an apparatus for adjusting the time of a clock if it is determined that the degree of adjustment is within a limit based on the clocks initial time
First Claim
1. A method of operating a free-running secure clock, wherein the clock has been initially set to a time, comprisingreceiving a request to adjust the time of the clock,determining if the degree of requested adjustment summed with prior adjustments, is within a limit based on the time to which the clock was initially set, andfor all requests to adjust the time of the clock, permitting such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
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Accused Products
Abstract
A free-running secure clock in a computing device that is adjustable by a user of the device so long as cumulative adjustments do not exceed a predicted clock drift. The clock may be initially set by the user or by a trusted time authority or the like. Such a clock may be required in a trust-based system that measures a temporal requirement against the clock.
38 Citations
16 Claims
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1. A method of operating a free-running secure clock, wherein the clock has been initially set to a time, comprising
receiving a request to adjust the time of the clock, determining if the degree of requested adjustment summed with prior adjustments, is within a limit based on the time to which the clock was initially set, and for all requests to adjust the time of the clock, permitting such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
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3. A method of operating a free-running secure clock, comprising
setting the clock to an initial time, receiving a request to adjust the time of the clock, determining if the degree of requested adjustment summed with prior adjustments is within a limit based on the time to which the clock was initially set, and for all requests to adjust the time of the clock, permitting such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
- 7. A free-running secure clock, the clock having been initially set to a time, wherein the clock, in response to a request to adjust its time determines if the degree of requested adjustment summed with prior adjustments is within a limit based on the time to which the clock was initially set and, for all requests to adjust the time of the clock, permits such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
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9. A free-running secure clock, wherein the clock has been initially set to a time, comprising
means for receiving a request to adjust the time of the clock, means for determining if the degree of requested adjustment summed with prior adjustments is within a limit based on the time to which the clock was initially set, and means for permitting, for all requests to adjust the time of the clock, such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
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11. A free-running secure clock, comprising
means for setting the clock to a time, means for receiving a request to adjust the time of the clock, means for determining if the degree of requested adjustment summed with prior adjustments is within a limit based on the time to which the clock was initially set, and means for permitting, for all requests to adjust the time of the clock, such a request if the degree of requested adjustment summed with prior adjustments is within the limit.
Specification