Key Generation with Nonce Masking Against Side-Channel Attacks
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Solution Overview
Problem
The PACE protocol is vulnerable to side-channel attacks, particularly due to unprotected processing of the nonce s and point Gc′ in key generation steps, which can reveal secret information through power consumption or electromagnetic radiation.
Innovation Solution
The method for key generation in the client processor device avoids operations that depend exclusively on the nonce s and public values by incorporating at least one non-public value into each operation, thereby blurring side-channel emissions and making side-channel attacks more difficult or impossible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the nonce s and point Gc' are processed unprotected in key generation steps, then the key generation is simple and fast, but side-channel information (power consumption, electromagnetic radiation) reveals secret information
Solution Approach 1:
The patent introduces an intermediary masking value that is combined with the nonce during point multiplication operations. This masking value acts as a mediator that obscures the relationship between the secret nonce and the computed points, preventing direct extraction of secret information from side-channel measurements while maintaining the mathematical correctness of the cryptographic operations
Solution Approach 2:
The patent changes the parameter representation by introducing masked versions of the nonce and generator point. Instead of using the raw secret nonce directly in computations, the system transforms it into a masked form that preserves functional equivalence for key generation while eliminating the direct correlation between power consumption patterns and the secret nonce value
2Reliability
If masking operations are added to protect against side-channel attacks, then security is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary masking actions where the masking value is prepared and combined with the nonce before the critical point multiplication operations. By performing the masking preparation in advance and integrating it seamlessly into the computation flow, the patent minimizes additional processing time while ensuring that the actual secret-dependent operations are already protected against side-channel analysis
Data Source
AI summary
A method for key generation is arranged in a client processor device, by means of which a second public client key Pc′ of the client is generated. The public key Pc′ is formed by a calculation, or sequence of calculations, which does not contain any operation whose result depends exclusively on the nonce s and at least one public value, or the public key Pc′ being formed by a calculation, or sequence of calculations, where into each operation in which the nonce s enters, at least one non-public value enters the first private client key kc or the second private client key kc′, for example as a result of the calculation Pc′=(kc′·s)•G+(kc′·kc)•Pt.