NAND Flash Memory Authentication via Asymmetric Key Segmentation
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Solution Overview
Problem
Current authentication methods in information security, particularly in devices like SD cards and semiconductor memory devices, face challenges in preventing unlawful use of secret information, especially when the authenticator has low tamper-resistance, leading to potential exposure of hidden information and unauthorized access.
Innovation Solution
A memory system configuration where the NAND flash memory acts as an authenticatee with high tamper-resistance, hiding first key information and generating session keys asymmetrically with the host device, ensuring that even if secret information leaks from the host device, it cannot be used to disguise the NAND flash memory, thereby preventing unlawful use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the authenticator (host device) stores secret information for authentication, then authentication functionality is enabled, but the host device's low tamper-resistance leads to potential exposure of secret information and unauthorized access
Solution Approach 1:
The patent extracts the most critical secret information (first key and secret identification information) from the host device and stores it in the NAND flash memory, which has high tamper-resistance. This separates the storage of critical secrets from the low tamper-resistance host device, preventing secret information exposure while maintaining authentication functionality.
Solution Approach 2:
The NAND flash memory acts as an intermediary with high tamper-resistance that securely holds the first key and secret identification information. This intermediary protects the secret information from the host device's low tamper-resistance, enabling secure authentication without direct exposure of secrets in the host device.
2Device complexity
If symmetric authentication keys are used between host device and NAND flash memory, then authentication is simplified, but leakage of host device secrets compromises the NAND flash memory's security
Solution Approach 1:
The patent implements asymmetric authentication where the NAND flash memory holds the first key and secret identification information, while the host device holds different authentication data. This asymmetric structure ensures that even if host device secrets leak, the NAND flash memory's security remains intact because it possesses unique secret information that cannot be derived from the host device's data.
Solution Approach 2:
The first key and secret identification information are pre-stored in the NAND flash memory during manufacturing, establishing a secure foundation before any authentication operations. This preliminary setup ensures that the high tamper-resistance property is established first, protecting subsequent authentication operations from host device vulnerabilities.
3Ease of operation
If secret identification information is stored in accessible memory areas, then read/write operations are flexible, but security is compromised allowing unauthorized access
Solution Approach 1:
The patent segments the memory into distinct areas with different security levels. The first memory area stores the first key and secret identification information with restricted access (prohibited from read/write outside the device), while other areas allow normal operations. This segmentation enables flexible access where needed while protecting critical secrets.
Solution Approach 2:
Different memory areas are assigned different security qualities: the first memory area has high security (prohibited from external read/write) for storing critical secret information, while other memory areas have lower security restrictions allowing normal read/write operations. This local quality differentiation enables both security and operational flexibility.
Data Source
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AI summary
According to one embodiment, an authentication method includes generating, by the memory, first authentication information by calculating secret identification information with a memory session key in one-way function operation, transmitting encrypted secret identification information, a family key block, and the first authentication information to a host, and generating, by the host, second authentication information by calculating the secret identification information generated by decrypting the encrypted secret identification information with the host session key in one-way function operation. The method further includes comparing, by the host, the first authentication information with the second authentication information.