Clock Frequency Dithering for Side-Channel Attack Countermeasures
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Solution Overview
Problem
Computing systems face vulnerabilities to side-channel attacks that exploit data-dependent power variations, which can be obscured by system noise, but existing countermeasures like single-frequency clock disabling degrade system performance.
Innovation Solution
Implementing a clock frequency dithering mechanism that randomly switches between different frequencies at random times during critical system operations, using a dither control circuit and oscillator to obscure time correlation between power and data sequences, while maintaining full system capability through minimal performance impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-frequency clock is disabled randomly to thwart side-channel attacks, then security against power variation attacks is improved, but system performance degrades due to execution time degradation
Solution Approach 1:
The patent changes the frequency parameter of the clock signal dynamically during operation. Instead of disabling the clock or using a single fixed frequency, the system varies the clock frequency among multiple available frequencies (e.g., f0, f1, f2) during critical operations. This frequency parameter change obscures power variation patterns while maintaining continuous operation and full system capability.
2Reliability
If clock frequency is varied during critical operations, then power variation patterns are obscured, but system complexity increases due to additional control circuits
Solution Approach 1:
The patent integrates the clock frequency dithering functionality into the existing clock module architecture. The channel selector and frequency control circuitry are incorporated within the standard clock module, allowing the same hardware to serve both normal clock distribution and security-enhanced frequency variation functions. This multi-functionality approach adds security capability without requiring entirely separate control systems.
Solution Approach 2:
The clock module performs the frequency variation autonomously based on control signals. The dither control circuit generates control signals that automatically switch between different clock frequencies during critical operations without requiring external intervention or complex external control logic. The system serves its own security function through integrated self-control mechanisms.
Data Source
AI summary
A computing system can be arranged to generate a range of different frequencies with at least one oscillator of a clock module prior to providing a first clock frequency to a controller with a channel selector of the clock module in response to a dither control circuit. A system operation may be executed with the controller before the first clock frequency is changed to a second clock frequency during the execution of the system operation as directed by the dither control circuit. The second clock frequency can be chosen from the range of different frequencies.The computing system may return to the first clock frequency at the conclusion of the execution of the system operation.