Signal generator based device security
First Claim
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1. A method comprising:
- repeatedly regenerating a cryptographic key in an integrated circuit;
wherein regenerating the key includes;
for each of a series of portions of a volatile value,selecting a configuration of a plurality of fixed oscillator circuits embodied in the integrated circuit, the configuration including a first plurality of oscillator circuits and a second plurality of oscillator circuits, the oscillation frequency of each oscillator circuit depending on fabrication characteristics of the semiconductor device,generating a plurality of numerical values, including generating a first numerical value dependent on the oscillation frequency of each of the oscillator circuits of the first plurality of oscillator circuits, and generating a second numerical value dependent on the oscillation frequency of each of the oscillator circuits of the second plurality of oscillator circuits, andforming the portion of the volatile value using the first numerical value and the second numerical value; and
generating the cryptographic key using the volatile value.
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Abstract
Subsets of multiple signal generator circuits embodied in a device are selected, and then a volatile value for the device is generated from the selected subsets. The volatile value may be used for authentication of the device and/or for cryptographic procedures performed on the device. The signal generator circuits may each comprise an oscillator circuit, and the selection of the subsets may be according to a comparison of the outputs of the subsets of circuits, for example, according to a comparison of output oscillation frequencies.
76 Citations
7 Claims
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1. A method comprising:
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repeatedly regenerating a cryptographic key in an integrated circuit; wherein regenerating the key includes; for each of a series of portions of a volatile value, selecting a configuration of a plurality of fixed oscillator circuits embodied in the integrated circuit, the configuration including a first plurality of oscillator circuits and a second plurality of oscillator circuits, the oscillation frequency of each oscillator circuit depending on fabrication characteristics of the semiconductor device, generating a plurality of numerical values, including generating a first numerical value dependent on the oscillation frequency of each of the oscillator circuits of the first plurality of oscillator circuits, and generating a second numerical value dependent on the oscillation frequency of each of the oscillator circuits of the second plurality of oscillator circuits, and forming the portion of the volatile value using the first numerical value and the second numerical value; and generating the cryptographic key using the volatile value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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Specification