Differential power analysis
AssigneeCryptography Research, Inc.
InventorsPaul C. Kocher, Joshua M. Jaffe, Benjamin C. Jun
Life of this patent
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Abstract
Information leaked from smart cards and other tamper resistant cryptographic devices can be statistically analyzed to determine keys or other secret data. A data collection and analysis system is configured with an analog-to-digital converter connected to measure the device's consumption of electrical power, or some other property of the target device, that varies during the device's processing. As the target device performs cryptographic operations, data from the A/D converter are recorded for each cryptographic operation. The stored data are then processed using statistical analysis, yielding the entire key, or partial information about the key that can be used to accelerate a brute force search or other attack.
Claims23
A cryptographic processing device for securely performing a cryptographic processing operation in a manner resistant to discovery of a secret by external monitoring of said device's power consumption, comprising:
- (a) an interface for receiving data to be cryptographically processed;
- (b) an interface for receiving an external clock signal;
- (c) an interface for receiving a variable amount of power, said power consumption varying measurably during said performance of said operation;
- (d) an analog source of unpredictable information;
- (e) an oscillator using an analog process to generate an internal clock signal:
- (i) said process incorporating said unpredictable information to adjust the frequency of said clock signal generated by said oscillator;
- and
- (f) a processor:
- (i) configured to cryptographically process said data;
- and
- (ii) clocked by said internal clock signal to produce unpredictable temporal differences in power consumption variations among said cryptographic processing operations, thereby increasing the difficulty of determining said secret by collecting power consumption measurements.
A device for securely performing a cryptographic processing operation in a manner resistant to discovery of a secret by external monitoring of variations in the amount of power consumed, comprising:
- (a) an interface for receiving data to be cryptographically processed;
- (b) a first processor:
- (i) configured to perform cryptographic operations involving a secret quantity;
- and
- (ii) characterized in having a measurable power consumption while performing said cryptographic operations;
- and
- (c) a second processor:
- (i) performing additional operations simultaneously with at least some of said cryptographic operations of said first processor;
- and
- (ii) characterized in having a measurable power consumption while performing said additional operations;
- wherein
- (d) said device is configured so that at least one of said processors:
- (i) is connected to a source of unpredictable information;
- and
- (ii) is configured to utilize said unpredictable information to consume unpredictable amounts of power, thereby increasing the difficulty of determining said secret quantity from external measurements of power consumption.
Dependencies are inferred from the claim text.