Variable Power Supply Voltage for Covert Channel Attack Defense
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Solution Overview
Problem
Existing electronic circuits are vulnerable to covert channel attacks, which involve analyzing electrical consumption and electromagnetic radiation to infer the operation of encryption circuits, and existing countermeasures are either complex to implement or insufficiently effective.
Innovation Solution
An electronic circuit with a voltage generator that supplies a variable power supply voltage with fluctuating electrical characteristics, including a fixed offset voltage, periodic voltages with variable frequencies and amplitudes, and phase shifts, generated by a number generator to introduce noise and make detection more complex.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed power supply voltage is used, then the circuit operation is stable and predictable, but the circuit becomes vulnerable to covert channel attacks through power analysis
Solution Approach 1:
The patent applies the dynamics principle by transforming the static power supply voltage into a dynamic one that varies over time according to a pseudorandom sequence. The power supply voltage Vcc is modulated by adding a variable component Vnoise that changes at each time step, making power analysis attacks ineffective while maintaining circuit functionality through proper asynchronous design
Solution Approach 2:
The patent implements parameter changes by modifying the power supply voltage parameter from a constant value to a time-varying value. The voltage parameter Vcc(t) = Vcc0 + Vnoise(t) changes its magnitude dynamically based on the pseudorandom sequence generated by the noise generator, thereby altering the electrical characteristics observed during power analysis
2Reliability
If a random number generator and digital-to-analog converter are added to create voltage fluctuations, then covert channel attacks are thwarted, but the circuit surface and power consumption increase
Solution Approach 1:
The patent applies self-service by using the circuit's own power supply line to generate the noise signal. The pseudorandom noise is injected directly into the power supply voltage, and the same power supply that feeds the logic circuit also carries the noise signal, eliminating the need for separate noise injection circuitry and reducing overall circuit area
Solution Approach 2:
The power supply circuit serves multiple functions: it provides the operating voltage to the logic circuit, generates the pseudorandom noise sequence, and distributes the noisy voltage throughout the circuit. This multi-functionality reduces the need for dedicated noise generation components, thereby minimizing circuit surface area
3Reliability
If current consumption modules are added to mask electrical consumption, then power analysis becomes more difficult, but the circuit complexity and power consumption increase significantly
Solution Approach 1:
The patent converts the harmful effect of power consumption into a beneficial security feature. Instead of trying to reduce or mask power consumption through additional components, the method uses the power supply line itself to inject noise, transforming the power consumption signature from a vulnerability into a source of security through the pseudorandom modulation
Data Source
AI summary
The electronic circuit comprises a logic module performing a first function. A number generator generates a series of first numbers. A voltage generator supplies the logic module with a first minimum operating voltage of the logic module and a variable additional second voltage having electrical characteristics that are functions at least of the first series of first numbers. The variable additional second voltage comprises at least a fixed voltage defined by an offset voltage value and a first periodic voltage defined at least by a first frequency and a first amplitude. The voltage generator is configured so that the value of the offset voltage, of the first frequency and/or of the first amplitude are defined at least from the series of first numbers.