Cryptographic Circuit Randomized Dummy Substitution Operations
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Solution Overview
Problem
Existing cryptographic systems are vulnerable to side-channel attacks, particularly when hackers monitor power consumption or timing signals during substitution operations in cryptographic algorithms, making it difficult to protect the secret key.
Innovation Solution
The implementation of a cryptographic circuit that performs a series of substitution operations, including a real substitution operation and one or more dummy operations, where the position of the real operation is randomly selected, along with randomizing the number and order of dummy operations, to obscure the secret key's manipulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy substitution operations are added to protect against side-channel attacks, then security against side-channel attacks is improved, but computational overhead increases
Solution Approach 1:
The patent applies partial action by performing a limited number of dummy substitution operations (typically 1-3) instead of excessive random operations. This provides sufficient protection against side-channel attacks while keeping the computational overhead acceptable. The dummy operations are performed in addition to the necessary real substitution operations, creating a mixed sequence that obscures the real operations without excessive delay.
Solution Approach 2:
The patent generates random values in advance to determine the number and positioning of dummy operations. This preliminary preparation of random sequences allows the system to quickly execute the mixed sequence of real and dummy operations without requiring complex real-time decision-making, thereby reducing the actual computational overhead during the cryptographic operation.
2Reliability
If the number of dummy operations is increased to better hide the real substitution operation, then security is improved, but processing time increases
Solution Approach 1:
The patent determines the optimal number of dummy operations based on security requirements rather than using excessive numbers. By carefully selecting a limited number of dummy operations (typically 1-3 per real operation), the system achieves adequate security protection while maintaining acceptable processing speed. This partial action approach avoids the productivity loss that would result from performing too many dummy operations.
3Reliability
If random positioning of real substitution operation is implemented, then security against side-channel attacks is improved, but device complexity increases
Solution Approach 1:
The patent generates random values in advance to determine the positioning of real substitution operations within the mixed sequence. This preliminary generation of random positioning information simplifies the circuit design, as the random positions are predetermined rather than requiring complex real-time random selection logic during the cryptographic operation.
Solution Approach 2:
The patent uses identical substitution operation logic for both real and dummy operations, copying the same computational structure. This approach simplifies the device design by reusing the same substitution circuitry rather than requiring different complex logic for real versus dummy operations, thereby reducing overall device complexity while maintaining security.
Data Source
AI summary
A cryptographic circuit performs a substitution operation of a cryptographic algorithm. For each substitution operation of the cryptographic algorithm, a series of substitution operations are performed by the cryptographic circuit. One of the substitution operations of the series is a real substitution operation corresponding to the substitution operation of the cryptographic algorithm. One or more other substitution operations of the series are dummy substitution operations. A position of the real substitution operation in said series is selected randomly.