Obfuscated L2P Map Management for Memory Security
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Solution Overview
Problem
Current host-cached logical-to-physical (L2P) mapping techniques in memory devices face security issues due to the inability of controllers to control host memory, leading to potential data corruption and unauthorized modifications, while also incurring latency and power costs from frequent translation map swaps.
Innovation Solution
Implementing obfuscated L2P mappings, where physical addresses are encrypted, allowing the controller to validate requests and protect data integrity by hashing logical and physical addresses, and speculatively obfuscating regions to reduce user experience impact by time-shifting processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If host-cached L2P mapping is implemented, then data access speed is improved, but security control is worsened due to inability to control host memory
Solution Approach 1:
The patent introduces an intermediary validation mechanism where the controller validates host-provided physical addresses through hashing operations. The controller hashes the host-provided physical address and compares it with an internally generated hash to verify authenticity, acting as a mediator that maintains security control while allowing host-cached L2P mapping to function.
Solution Approach 2:
The system implements feedback through validation operations where the controller checks the integrity of host-provided physical addresses by comparing hash values. This feedback mechanism ensures that only valid, authorized physical addresses are used for data access, maintaining security while enabling fast host-cached operations.
2Adaptability or versatility
If frequent translation map swaps are performed, then data access flexibility is improved, but latency is worsened
Solution Approach 1:
The host performs preliminary action by pre-calculating and providing physical addresses along with validation data (hashes) for future data access operations. This eliminates the need for real-time translation map swaps during data access, as the host has already prepared the necessary mapping information in advance.
Solution Approach 2:
The host maintains a cached copy of L2P mapping information in its memory, copying the essential mapping data from the controller. This allows the host to provide physical addresses directly without requiring frequent swaps of translation maps between the controller and host, reducing latency while maintaining flexibility.
3Reliability
If on-the-fly obfuscation is performed, then security is improved, but power consumption is worsened
Solution Approach 1:
The obfuscation (hashing) operation is performed preliminarily by the host before data access, rather than on-the-fly during the access operation. The host calculates the hash of the physical address in advance and provides it to the controller, which then validates it without requiring computationally intensive real-time hashing operations.
Solution Approach 2:
The patent replaces the traditional mechanical approach of real-time hash calculation and comparison with a more efficient system where the host pre-calculates hashes and the controller performs simple validation by comparing pre-computed hash values, significantly reducing the computational power required during actual data access operations.
Data Source
AI summary
Devices and techniques for efficient obfuscated logical-to-physical mapping are described herein. For example, activity corresponding to obfuscated regions of an L2P map for a memory device can be tracked. A record of discontinuity between the obfuscated regions and L2P mappings resulting from the activity can be updated. The obfuscated regions can be ordered based on a level of discontinuity from the record of discontinuity. When an idle period is identified, an obfuscated region from the obfuscated regions is selected and refreshed based on the ordering.