Cryptographic Masking Conversion With Forced Carry Bit Flow
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cryptographic algorithms face challenges in protecting against side channel attacks, particularly in algorithms combining Boolean and arithmetic functions, due to the need for conversions between different masking schemes which are computationally expensive and vulnerable to side-channel attacks.
Innovation Solution
A method is introduced that forces a specific type of calculation to always result in a set carry bit by extending the parameters of Boolean and arithmetic masking schemes, ensuring a uniform and data-independent program flow, thereby reducing the visibility of side-channel attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conversion between Boolean masking and arithmetic masking is performed, then protection against side channel attacks is improved, but computational complexity increases
Solution Approach 1:
The patent extracts the problematic conversion step between Boolean and arithmetic masking schemes and removes it by operating entirely within the arithmetic masking domain. This eliminates the source of computational complexity while maintaining protection against side channel attacks through consistent arithmetic masking throughout the cryptographic operations.
Solution Approach 2:
The patent changes the masking parameter representation by extending the bit-length of arithmetic masking parameters. By using extended precision arithmetic masking (e.g., operating with n+1 bits instead of n bits), the patent enables secure operations without requiring conversion to Boolean masking, thus reducing computational complexity while maintaining security.
2Reliability
If multiple masking scheme conversions are performed, then security against differential power analysis is improved, but processing time increases
Solution Approach 1:
The patent maintains continuous operation within the arithmetic masking domain without interrupting the computational flow for masking scheme conversions. By keeping all operations (AND, OR, XOR, addition, multiplication) within the same arithmetic masking framework, the patent eliminates time-consuming conversion steps while maintaining continuous cryptographic processing and security protection.
3Stability of the object's composition
If parameters are extended to force set carry bit, then uniform program flow is achieved, but data processing complexity increases
Solution Approach 1:
The patent solves the carry bit problem by adding an extra dimension (bit) to the parameter representation. By extending parameters from n bits to n+1 bits, the patent creates additional space to force the carry bit to a fixed value (typically 0), thereby achieving uniform program flow. This dimensional extension allows arithmetic operations to proceed with predictable carry behavior without complex conditional logic.
Data Source
AI summary
Solutions described herein refer to cryptographic data processing, utilizing a first masking scheme of a shared secret and a second masking scheme of the shared secret, wherein a transformation from the first masking scheme to the second masking scheme is conducted by forcing one type of calculation among at least two types of calculations.