AES Masking Lookup Tables for Lower-Power Side-Channel Protection
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Solution Overview
Problem
Existing side-channel attack mitigation methods in cryptographic algorithms like AES consume excessive power due to complex functions, particularly those involving finite-field arithmetic, and require high redundancy levels that can lead to power leaks.
Innovation Solution
Replace functions in finite-field arithmetic with lookup tables (LUTs) and combine them with redundancy-based protection, reducing redundancy levels and power consumption while maintaining protection levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex finite-field arithmetic functions are used in AES, then cryptographic security is maintained, but power consumption increases excessively
Solution Approach 1:
The patent replaces complex finite-field arithmetic functions with pre-computed lookup tables that store the results of these operations. By copying pre-calculated values into tables, the system avoids performing power-intensive arithmetic operations during encryption, thereby reducing power consumption while maintaining cryptographic security through the use of equivalent substitution operations.
Solution Approach 2:
The patent changes the operational parameters by switching from standard byte representation to redundant representation with extended bit length (8+d bits). This parameter change allows the use of simpler lookup table operations instead of complex finite-field arithmetic, reducing power consumption while maintaining security through the redundancy property that provides resistance against side-channel attacks.
2Reliability
If high redundancy levels are used for side-channel attack mitigation, then protection level increases, but power leaks increase
Solution Approach 1:
The patent uses lookup tables to store pre-computed redundant representations, allowing the system to achieve protection against side-channel attacks without performing power-intensive operations. The copied values in the tables provide the necessary redundancy for attack mitigation while avoiding the power leaks associated with real-time computation of high-redundancy operations.
3Reliability
If redundant bytes with extended bits are used, then side-channel attack resistance improves, but computational complexity increases
Solution Approach 1:
The patent resolves the complexity issue by copying pre-computed results into lookup tables. Instead of performing complex computations with redundant bytes during encryption, the system simply retrieves pre-calculated values from tables, thereby maintaining side-channel attack resistance through redundant representation while dramatically reducing computational complexity.
4Use of energy by moving object
If lookup tables are used to replace finite-field arithmetic, then power consumption decreases, but processing frequency increases
Solution Approach 1:
The patent achieves both reduced power consumption and increased processing frequency by using lookup tables that store pre-computed values. The copying of results into tables enables rapid retrieval operations that consume less power and execute faster than real-time finite-field arithmetic, thereby improving both energy efficiency and processing speed simultaneously.
Data Source
AI summary
Techniques include replacing many of the functions used in finite-field-based arithmetic with lookup tables (LUTs) and combining such LUTs with redundancy-based protection. Advantageously, using LUTs makes it possible to dramatically decrease the redundancy level (e.g., from d=8 to d=3 or 4) and the power consumption and increase the maximal frequency, while preserving the same protection level, latency and performance. The improvement is applicable not only to AES, but also to other algorithms based on a finite field arithmetic, and in particular SM4, ARIA, and Camellia which use Sboxes very similar to or the same as the AES Sbox.