Authenticator Session Key Generation via Asymmetric Key Segmentation
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Solution Overview
Problem
Current authentication systems face challenges in preventing unlawful use of secret information, especially when the authenticator has low tamper-resistance, as it can lead to exposure of high tamper-resistance secret information, and there is a need for solutions that do not require large circuit scales for public key cryptosystems.
Innovation Solution
An authenticator system that generates a session key using second key information hidden in the NAND flash memory and random number information, with the first key information being hidden in a high tamper-resistance area and not derivable from the second key information, ensuring asymmetric secrecy levels between the authenticator and authenticatee, and implementing this without requiring large circuit scales.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the authenticator uses software implementation with low tamper-resistance, then the device complexity and circuit scale are reduced, but the secret information becomes vulnerable to extraction and unlawful use
Solution Approach 1:
The secret information is segmented into two distinct parts: first key information stored in high tamper-resistance hardware (NAND flash memory) and second key information stored in low tamper-resistance software (host device memory). This segmentation allows the system to leverage both hardware security and software flexibility, reducing overall device complexity while maintaining security through the不可逆 relationship between the two key parts.
Solution Approach 2:
The patent implements asymmetric secrecy levels where the first key information has high secrecy (stored in tamper-resistant hardware) and the second key information has low secrecy (stored in software). This asymmetry resolves the contradiction by allowing the low-secrecy component to reduce device complexity while the high-secrecy component maintains security against tampering.
2Device complexity
If the first key information is derived from the second key information, then the authentication process is simplified, but the security is compromised as the high tamper-resistance secret can be extracted through the low tamper-resistance path
Solution Approach 1:
Instead of deriving the secure first key from the insecure second key (which would compromise security), the patent inverts the relationship: the insecure second key is derived from the secure first key through a one-way function. This inversion allows simplification of the authentication process while preventing secret information exposure, as the derivation direction ensures that compromising the second key does not reveal the first key.
3Reliability
If public key cryptosystem is implemented in hardware to ensure security, then the tamper-resistance is improved, but the circuit scale becomes too large for practical implementation
Solution Approach 1:
The patent extracts the complex public key cryptosystem implementation from hardware and relocates it to software in the host device. Only essential cryptographic functions are implemented in the NAND flash memory controller, significantly reducing circuit scale while maintaining security through the asymmetric key relationship and one-way derivation function.
Solution Approach 2:
The patent replaces hardware-based cryptographic mechanisms with software-based cryptographic operations in the host device. This substitution reduces the circuit scale of the authenticator while maintaining security through software implementation of cryptographic protocols, leveraging the fact that software can perform complex cryptographic operations without requiring large hardware circuits.
Data Source
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AI summary
According to one embodiment, an authenticator which authenticates an authenticatee, which stores first key information (NKey) that is hidden, includes a memory configured to store second key information (HKey) which is hidden, a random number generation module configured to generate random number information, and a data generation module configured to generate a session key (SKey) by using the second key information (HKey) and the random number information. The authenticator is configured such that the second key information (HKey) is generated from the first key information (NKey) but the first key information (NKey) is not generated from the second key information (HKey).