Encryption Processing with Masked Tables for Side-Channel Resistance
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Solution Overview
Problem
Existing encryption methods face challenges in balancing resistance to side-channel attacks while maintaining processing speed and minimizing circuit size, with conventional methods either compromising on speed or resistance.
Innovation Solution
An encryption processing apparatus that generates and uses multiple random mask values and masked non-linear transformation tables concurrently with encryption operations, selecting and rearranging them randomly to enhance resistance to side-channel attacks without significant speed or size penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the masking method is implemented to resist side-channel attacks, then security against side-channel attacks is improved, but processing speed decreases due to dynamic generation of masked non-linear transformation tables
Solution Approach 1:
The patent pre-generates multiple masked non-linear transformation tables using different mask values before the encryption process. These tables are stored in advance, eliminating the need to dynamically generate tables during encryption operations. This preliminary action resolves the contradiction by maintaining security through multiple masked tables while avoiding the processing time penalty of dynamic table generation.
Solution Approach 2:
The patent dynamically selects and rearranges mask values and corresponding masked non-linear transformation tables during encryption operations. The selection unit randomly chooses from pre-generated tables, and the rearrangement unit shuffles the order of table usage across different encryption operations. This dynamic approach maintains security by preventing predictable patterns while using pre-generated tables to avoid processing speed degradation.
2Reliability
If multiple mask values and masked non-linear transformation tables are used to enhance security, then resistance to side-channel attacks is improved, but device complexity increases
Solution Approach 1:
The patent segments the masking function into separate components: a selection unit that chooses mask values and corresponding tables, and a rearrangement unit that shuffles their usage order. This segmentation allows the system to manage multiple mask values and tables in an organized manner, reducing the complexity burden while maintaining enhanced security through diverse masking strategies.
Solution Approach 2:
The patent changes the parameter of mask values dynamically during encryption operations. By randomly selecting from multiple pre-generated mask values and rearranging table usage patterns, the system creates variability in the encryption process without requiring additional hardware complexity. This parameter change approach maintains security through unpredictability while avoiding circuit size increases.
3Reliability
If mask values are rearranged randomly for each encryption operation, then resistance to side-channel attacks is improved, but processing speed decreases due to additional selection and rearrangement operations
Solution Approach 1:
The patent performs the selection and rearrangement of mask values and tables as preliminary actions before the main encryption computation. The selection unit pre-determines which tables to use, and the rearrangement unit pre-shuffles their order based on random seeds. This preliminary preparation eliminates the need for complex runtime decisions during encryption, maintaining security through randomization while preserving processing speed.
Data Source
AI summary
An encryption processing apparatus includes a table generation unit configured to generate a masked non-linear transformation table using a random number as a mask value, a storage unit configured to store the mask value and the masked non-linear transformation table, a first selection unit configured to select, from among the mask value and the masked non-linear transformation table that are stored in the storage unit, one set of a mask value and a masked non-linear transformation table that are to be rewritten, an operation unit configured to perform an operation using the mask value and the masked non-linear transformation table, and a second selection unit configured to select, from among the mask value and the masked non-linear transformation table that are stored in the storage unit, the mask value and the masked non-linear transformation table that are to be used by the operation unit.