Asymmetric Cryptographic Procedure Masking Horizontal Attacks
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Solution Overview
Problem
Existing cryptographic protocols in processing devices are vulnerable to Horizontal Attacks, which allow attackers to recover secret key bits by analyzing read/write patterns, particularly in asymmetric cryptography like RSA and ECC, where attackers can exploit conditional swap operations and random bit generation to infer key bits.
Innovation Solution
Implementing an asymmetric cryptographic procedure that performs iterative operations on operands using a secret key, with conditional swaps based on a control bit value obtained through a logic XOR function with a random bit, and utilizing mask registers to randomize key bits, thereby masking the secret key and reducing leakage points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conditional swap operations are used in asymmetric cryptography, then cryptographic functionality is achieved, but vulnerability to Horizontal Attacks increases
Solution Approach 1:
The patent applies preliminary action by introducing random bit generation and mask register initialization before the main cryptographic computation. The mask registers are prepared with random values prior to the iterative operations, and the random bits are generated in advance to control the conditional swaps, thereby preemptively obscuring the relationship between secret key bits and observable operations.
Solution Approach 2:
The patent uses mask registers as intermediaries between the secret key and the cryptographic operations. These mask registers contain random values that mediate the connection between secret key bits and the operands used in conditional swap operations, preventing direct observation of key bits through side-channel analysis.
Solution Approach 3:
The patent changes parameters by introducing random bit values to control conditional swap operations instead of directly using secret key bits. The random bits serve as dynamic control parameters that change each iteration, transforming the fixed relationship between key bits and operations into a variable relationship that resists statistical analysis.
2Productivity
If secret key bits are directly used to control operations, then computational efficiency is maintained, but key leakage through read/write patterns occurs
Solution Approach 1:
The patent prepares mask registers with random values before the cryptographic computation begins. This preliminary action ensures that when conditional swaps occur during efficient iterative operations, the control decisions are based on random bits combined with key bits rather than raw key bits, preventing leakage while maintaining operational speed.
Solution Approach 2:
The patent transforms the control parameter from direct secret key bits to randomized control values derived from XORing key bits with random bits. This parameter change allows the conditional swap operations to remain computationally efficient while the randomized control values prevent attackers from inferring key bits through analysis of operation patterns.
3Reliability
If random bit generation is implemented for each iteration, then resistance to Horizontal Attacks improves, but computational overhead increases
Solution Approach 1:
The patent generates random bits in advance for each iteration before the main computational loop. By preparing these random control values preliminarily, the patent ensures that the main iterative computation can proceed efficiently without generating random bits during each expensive operation, balancing security requirements with computational performance.
Solution Approach 2:
The patent implements random bit generation selectively for control purposes rather than for all computational operations. By applying randomness only where needed for conditional swap control and not throughout the entire computation, the patent achieves adequate attack resistance while avoiding excessive computational overhead that would result from的全面 randomization.
Data Source
AI summary
A method performs cryptographic operations on data in a processing device. An iterative operation between a first operand formed by a given number of words and a second operand using a secret key is performed. The iterative operation includes, for each bit of the secret key, applying one of a first set operations and a second set of operations to the first operand and to the second operand depending on of the bit, and conditionally swapping words of the first and the second operand based on a control bit value obtained by applying a logic XOR function to a random bit.