Signed Cryptography Masking Without Sign Bit Leakage
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Solution Overview
Problem
Side-Channel Analysis (SCA) attacks pose a significant threat to cryptographic implementations by exploiting information from power consumption or electromagnetic radiation, and existing countermeasures like masking increase overhead costs in terms of power, area, and latency.
Innovation Solution
A method that eliminates the sign bit in masking operations by altering the order of cryptographic operations, ensuring all results are positive, thus preventing probing attacks that rely on sign bit distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If masking operations are performed using conventional methods with sign bit, then cryptographic operations can be performed, but security is compromised due to sign bit leakage to SCA attacks
Solution Approach 1:
The patent extracts and eliminates the sign bit from the masking operations. By removing the sign bit that causes information leakage, the invention prevents SCA attacks while maintaining the functional correctness of cryptographic operations through alternative unsigned arithmetic approaches
Solution Approach 2:
The patent changes the parameter representation by using unsigned arithmetic instead of signed arithmetic. This parameter change eliminates the sign bit while maintaining the mathematical correctness of masking operations, thereby preventing sign bit leakage to side-channel attacks
2Reliability
If conventional masking is applied to mitigate SCA attacks, then security is improved, but overhead costs increase in terms of power, area, and latency
Solution Approach 1:
By extracting and removing the problematic sign bit component, the invention achieves security against SCA attacks without requiring the full overhead of conventional masking schemes. This selective removal reduces computational complexity while maintaining security
Solution Approach 2:
The patent uses disposable random values (masking constants) that are generated and then discarded after use. This approach provides security through single-use masking without requiring complex reusable masking structures, reducing overall system overhead
Data Source
AI summary
Generally discussed herein are devices, systems, and methods for secure cryptographic masking. A method can include generating a first random number, determining a result of the first random number modulo a prime number resulting in a second random number, subtracting the second random number from the prime number resulting in a first subtraction result, adding a private key value to the first subtraction result resulting in a first split, and responsive to determining the private key value is less than the random number, providing the first split and the second random number as splits of the private key.