Cryptographic Tool Deterministic Secret Generation
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Solution Overview
Problem
Cryptographic calculation tools, such as smart cards, are vulnerable to 'template attacks' that target the random number generator, allowing attackers to characterize its defects and biases, enabling the determination of secret keys by creating reference consumption curves.
Innovation Solution
Replacing the random number generator with a deterministic process that uses input data to generate a secret stimulus, ensuring identical output each time, thereby eliminating the need for averaging and making 'template attacks' ineffective, and incorporating a secret hash function or modified encryption algorithms like DES or AES to counter DPA attacks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a random number generator is used to generate secret information for counteracting DPA attacks, then the cryptographic tool becomes resistant to differential power analysis, but it becomes vulnerable to template attacks that can characterize the random number generator's defects and biases
Solution Approach 1:
The patent extracts and removes the random number generator from the cryptographic tool, replacing it with a deterministic process. This eliminates the source of vulnerability to template attacks while maintaining the necessary secret information generation through a different mechanism that does not rely on random number generation.
Solution Approach 2:
The patent changes the fundamental parameter of secret information generation from random (non-deterministic) to deterministic. By using a deterministic process that generates the same secret information for the same input data, the system maintains DPA attack resistance while eliminating template attack vulnerability, as template attacks rely on characterizing random number generator defects.
2Object-affected harmful factors
If a deterministic process is used to generate secret information, then template attacks become ineffective, but the system must ensure identical output for identical input which requires careful design
Solution Approach 1:
The patent introduces an intermediary deterministic process that takes input data and generates secret information without requiring a random number generator. This intermediary mechanism uses cryptographic operations and secret keys to produce the necessary secret information in a deterministic manner, simplifying the overall design while maintaining security.
3Reliability
If random numbers are mixed with data before processing, then correlations are broken and DPA attacks fail, but the random number generator must be modified in software or hardware which increases complexity
Solution Approach 1:
The patent removes the random number generator component entirely from the cryptographic tool. By extracting this vulnerable component, the system eliminates the need for complex software or hardware modifications to integrate a random number generator, while still achieving the goal of breaking correlations through the deterministic secret information generation process.
Data Source
AI summary
The secure cryptographic computing process includes processing an input (D) by a cryptographic computing tool involving at least one encryption key (K) and at least one generated secret, so as to provide an output (DC). The generation of said at least one secret (ST) includes processing said input by at least one operator (OPS) possessing at least one secret characteristic.