Cryptography Circuit Customized Masking Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cryptography circuits are vulnerable to observation attacks, where physical quantities like power consumption and electromagnetic radiation reveal sensitive information, compromising security, especially against higher-order attacks that exploit variance in leak information.
Innovation Solution
A cryptography circuit protected by masking, where binary words are unmasked before nonlinear processing and remasked after, using a set of specific masks stored in ROM memory, with secondary masks generated through permutation and random selection, reducing complexity and making attacks more difficult.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If masking is applied to protect against observation attacks, then security against first-order attacks is improved, but circuit complexity increases
Solution Approach 1:
The circuit is divided into multiple functional blocks (e.g., S-boxes, linear transformation units) that process masked data independently. Each block operates on shares of secret data rather than the full secret, allowing parallel processing and reducing the complexity of individual components while maintaining overall security.
Solution Approach 2:
The patent transforms the representation of secret data by splitting it into multiple shares (parameters) that can be processed separately. By changing from a single secret value to multiple shares, the circuit can apply masking techniques that protect against observation attacks without requiring complete redesign of the cryptographic algorithm.
2Reliability
If random masking is used to prevent cataloging attacks, then security against higher-order attacks is improved, but the cost of implementing protection increases
Solution Approach 1:
Masking values are pre-computed and stored in lookup tables before the cryptographic operation begins. This preliminary preparation allows the main computation to proceed efficiently without real-time masking overhead, reducing both implementation cost and computational complexity while maintaining protection against cataloging attacks.
Solution Approach 2:
The patent uses multiple copies of the same cryptographic function operating in parallel, each processing different shares of the secret data. This copying approach allows the circuit to achieve higher-order security through composition of first-order protected operations without requiring fundamentally new high-order masking techniques.
3Measurement precision
If more measurements are taken to overcome noise in observation attacks, then attack effectiveness is improved, but the time required for attacks increases
Solution Approach 1:
The patent introduces random masking values as intermediaries between the secret data and the physical implementation. These masking values act as a mediator that obscures the relationship between secret data and observable physical quantities (power consumption, electromagnetic radiation), making statistical analysis and measurement-based attacks significantly more difficult and time-consuming.
Data Source
AI summary
A cryptography circuit protected by masking, said circuit including means for encrypting binary words using at least one key krc, means for applying linear processing operations and nonlinear processing operations to said words and means for masking said words. The binary words are unmasked upstream of the nonlinear processing operations by using a mask kri and masked downstream of said processing operations by using a mask kr+1i, the masks kri and kr+1i being chosen from a set of masks that is specific to each instance of the circuit.