Securing Crystals-Dilithium Verification Against Fault Attacks
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Solution Overview
Problem
The Dillithium lattice-based cryptographic scheme is vulnerable to fault attacks during the signature verification process, which could lead to the acceptance of forged signatures.
Innovation Solution
A method is introduced to secure the Dillithium signature verification process against fault attacks by detecting and preventing attacks that aim to verify conditions P1, P2, or P3, ensuring that a forged signature is not accepted even if a fault attack occurs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the Dillithium signature verification algorithm is implemented without additional security measures, then the verification process is simple and fast, but it is vulnerable to fault attacks that could lead to acceptance of forged signatures
Solution Approach 1:
The patent applies preliminary action by performing fault detection checks before the final signature acceptance decision. The verification algorithm includes intermediate checks that detect potential fault attacks early in the verification process, preventing forged signatures from being accepted while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent implements feedback mechanisms where the verification process continuously monitors intermediate results and compares them against expected values. When deviations are detected (indicating potential fault attacks), the system provides feedback to reject the signature, creating a self-correcting verification process that enhances security without significantly increasing complexity.
2Reliability
If additional verification steps are added to detect fault attacks, then security against forged signatures is improved, but the verification time and processing complexity increase
Solution Approach 1:
The patent applies partial action by implementing selective verification checks that focus on the most critical aspects of fault detection. Rather than verifying every possible parameter, the algorithm performs targeted checks on key intermediate values that are most susceptible to fault attacks, achieving adequate security with minimal additional time overhead.
Data Source
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AI summary
The present invention relates to a method for securing against fault attacks the execution of the verification of a Crystals-Dilithium post-quantum digital signature σ of a message M comprising a challenge seed c̃, a test vector z and a hint vector of polynomials h generated with a secret key sk = (ρ, K, tr, s1, s2, t0), said digital signature verification taking as inputs, said digital signature σ, said message M and a public key pk = (ρ, t1) and comprising a step of ensuring that a fault attack aiming at verifying one of the conditions P1, P2 and P3 does not lead to accept a forged signature, where : ct1.2d=0, ‖ct1.2d‖∞<βand‖LowBitsq(Az−ct1.2d,2γ2‖∞<γ2−β, ‖ct1.2d‖∞<γ2.