Cryptographic Module Power Analysis Resistance via Alternating Data Selection
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Solution Overview
Problem
Conventional cryptographic devices are vulnerable to power analysis attacks, as the power consumption patterns reveal confidential data during cryptographic operations, making it possible to retrieve sensitive information.
Innovation Solution
A cryptographic module is designed with a selection circuit that alternately selects and outputs data from two registers, one containing input data and the other containing disturbance data unrelated to the cryptographic operation, thereby creating a power consumption pattern that masks the actual data usage, making it difficult to retrieve confidential information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a register retains data to be subjected to cryptographic operations, then the cryptographic operation can be performed, but the power consumption pattern reveals confidential data making the system vulnerable to power analysis attacks
Solution Approach 1:
The patent divides the data retention function into multiple registers: a first register for retaining input data and a second register for retaining reverse data. This segmentation allows the system to separate the retention of operational data from the retention of reverse data, enabling power analysis resistance while maintaining cryptographic functionality through coordinated operation of multiple specialized registers
Solution Approach 2:
The patent introduces a selection circuit as an intermediary component that alternately selects and outputs contents from the first register (input data) and the second register (reverse data). This intermediary mechanism masks the power consumption patterns by creating alternating selection behavior, preventing direct correlation between power consumption and confidential data operations
2Reliability
If reverse data is retained in a register, then power analysis resistance is improved, but the power consumption of the register retaining normal data and the power consumption of the register retaining reverse data do not necessarily cancel out, leaving confidential data exposed
Solution Approach 1:
The patent implements dynamic alternating selection between the first register (input data) and the second register (reverse data) through the selection circuit. This dynamic switching creates time-varying power consumption patterns that do not consistently reveal confidential data, as the selection changes based on operational requirements rather than statically retaining data that would produce consistent power leakage patterns
3Productivity
If data is completely unhidden in the register, then the cryptographic operation can proceed efficiently, but power analysis attacks can easily retrieve confidential data
Solution Approach 1:
The patent converts the potentially harmful effect of power consumption into a beneficial masking mechanism. By having the selection circuit alternately select between input data and reverse data, the system uses the power consumption of the selection process itself to mask and obscure the power consumption patterns that would otherwise reveal confidential data, turning a vulnerability into a protective feature
Data Source
AI summary
A cryptographic module that performs a cryptographic operation is provided with: a register that retains first data related to key data to be used in the cryptographic operation; a register that retains second data without dependency on the first data; a selector that alternately selects and outputs the contents of the register retaining the first data and the register retaining the second data; and a left shift circuit that performs a predetermined shift operation on data outputted from the selector.