Cryptographic Data Masking Against Passive Sniffing
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Solution Overview
Problem
Cryptographic algorithms are vulnerable to passive sniffing attacks, which allow attackers to extract sensitive information by analyzing electromagnetic radiation, power consumption, and execution time, despite existing countermeasures being insufficient to protect against all scenarios.
Innovation Solution
A method that masks data processed by the cryptographic algorithm using a transformation step of the form x′=x·L+c, where x is the data to be masked, x′ is the masked data, c is a codeword from a linear code, and L is a matrix of linearly independent vectors not in the code, allowing for secure execution and detection of faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional countermeasures against passive sniffing are used, then some protection is provided, but they are insufficient to protect against all attack scenarios
Solution Approach 1:
The patent applies parameter changes by transforming the data representation from standard binary form to a masked form using a specific mathematical transformation. The data is transformed according to the rule: for each bit position i, compute (data[i] XOR mask[i]) AND (data[i] OR mask[i])^2, where mask is a randomly generated mask. This parameter transformation makes the data indistinguishable to passive sniffing attacks while preserving cryptographic functionality.
Solution Approach 2:
The patent introduces an intermediary masking layer between the cryptographic algorithm and the external environment. This mask acts as a mediator that prevents direct observation of sensitive data by attackers while allowing legitimate operations to proceed. The mask is applied to all data processing operations, creating a secure intermediary layer that protects against passive sniffing.
2Reliability
If data masking is applied to protect against passive sniffing, then security is improved, but computational complexity increases
Solution Approach 1:
The masking operation is designed to be self-service in that it automatically protects data without requiring additional external intervention or complex control mechanisms. The mask is applied consistently across all data processing operations, and the transformation is reversible through a simple inverse operation, eliminating the need for complex management systems.
Solution Approach 2:
The patent uses parameter changes with a specific mathematical transformation that balances security and efficiency. The transformation rule (data[i] XOR mask[i]) AND (data[i] OR mask[i])^2 provides strong protection against passive sniffing while maintaining computational efficiency through standard bitwise operations that can be implemented with simple hardware circuits.
3Productivity
If a mask is used multiple times for security, then reusability is improved, but security may be compromised
Solution Approach 1:
The patent applies dynamics by making the mask random and potentially changing for each cryptographic operation. Rather than using a static mask that could be reused indefinitely, the system generates a new random mask for each operation or uses a dynamically changing mask. This dynamic approach allows the same masking mechanism to be used repeatedly while maintaining security through randomness.
Solution Approach 2:
The mask parameter is changed for each cryptographic operation through random generation. The transformation rule uses a randomly generated mask that is different for each operation, allowing the masking mechanism to be reused indefinitely while maintaining security. The randomness ensures that even if the same algorithm is executed multiple times, the masks will be different, preventing pattern recognition by attackers.
Data Source
AI summary
The invention relates in particular to a method for securing the execution of a cryptographic algorithm (ALG) against passive sniffing, the method implementing masking (MSK) of data processed by the cryptographic algorithm. The masking (MSK) of said data includes a linear encoding step such as x′=x·L+c, in which x is the data to be masked, x′ is the corresponding masked data, c is a code word included in a linear code C, and L is a matrix made up of linearly independent vectors not included in the linear code C. The invention also relates to a device (SC) implementing such a method.