Microcircuit Decoy Function for Power Analysis Attack Defense
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Solution Overview
Problem
Existing methods for protecting microcircuits against power consumption analysis-based attacks are ineffective as attackers can detect and disrupt the execution of protection functions by analyzing electrical signatures, allowing them to prevent the setting of a 'kill-card' flag that prohibits microprocessor operation.
Innovation Solution
Implementing a decoy function that simulates the electrical signature of the protection function, including writing operations in non-volatile memory, to deceive attackers into thinking the protection function is being executed, thereby maintaining the microcircuit's operation and preventing power supply cutoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection function is implemented to detect and respond to attacks by setting a kill-card flag in non-volatile memory, then the microcircuit's security is improved, but the electrical consumption signature becomes distinctive and detectable by attackers
Solution Approach 1:
The patent creates a decoy function that copies the electrical consumption signature of the protection function. The decoy function performs dummy write operations to a different memory address that consume the same amount of electrical power as the actual protection function, making it indistinguishable to power analysis attacks. This copying of the signature without copying the actual protective action neutralizes the attack detection capability.
2Reliability
If write operations are performed in non-volatile memory to set the kill-card flag, then the protection function becomes effective, but the distinctive electrical consumption allows attackers to detect and disrupt the operation
Solution Approach 1:
The patent introduces a decoy function as an intermediary that mediates between the attacker's detection capability and the actual protection function. The decoy performs dummy operations that consume the same electrical power, acting as a shield that prevents the attacker from detecting when the real protection function is executing. This intermediary layer masks the distinctive signature of the protective write operations.
3Object-generated harmful factors
If the decoy function has the same electrical consumption signature as the protection function, then attacker detection becomes impossible, but the system complexity increases
Solution Approach 1:
The patent segments the memory addressing space into at least two different addresses: one for the actual kill-card flag and another for the decoy function. This segmentation allows the system to perform distinguishable operations (writing to different addresses) that produce the same electrical consumption signature. The segmentation simplifies the implementation by using a straightforward address comparison mechanism rather than requiring complex signature generation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The decoy function effectively neutralizes the attack by maintaining the microcircuit's operation and preventing power supply disruption, as the attacker cannot distinguish between the decoy and protection functions based on electrical consumption, thus rendering the attack ineffective.
Implementation Method 1
power consumption analysis ('side channel attacks with power analysis')
Implementation Method 2
different operations consume different amounts of electricity. These different operations thus have different signatures in terms of electrical consumption
Data Source
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Figure 3
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AI summary
The method for protecting a microcircuit against an attack comprises: - a step (205) of determining whether an attack is detected, - if an attack is detected, a step (210, 510) of implementing a protection function, and - if no attack is detected, a step (215, 515) of implementing a decoy function simulating the protection function and being perceptible, from outside the microcircuit, in a manner substantially identical to the protection function. In some embodiments, the decoy function has a power consumption substantially identical to that of the protection function, the protection function performs a step of writing predetermined data to a first address of non-volatile memory, and the decoy function performs a step of writing to non-volatile memory at a second address different from the first address.