Encrypted L2P Pointer Caching for Flash Memory Security

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Solution Overview

Problem

Current memory systems face challenges in securing data access and integrity due to the exposure of physical addresses when caching logical-to-physical (L2P) pointers at the host device, which can lead to vulnerabilities and unintended modifications.

Innovation Solution

Encrypting physical addresses included with L2P pointers cached at the host device using a cryptographic key, allowing the memory system to generate and decrypt encrypted L2P pointers, thereby protecting the physical address structure and preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If L2P pointers are cached at the host device for faster access, then access speed is improved, but security is worsened due to exposure of physical addresses

Engineering Contradiction:
Improveaccess speedVSAvoidsecurity vulnerability
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an encrypted L2P pointer as an intermediary between the host device and the memory array. Instead of caching plain physical addresses, the host caches encrypted versions that cannot be used to derive other physical addresses or access unauthorized memory locations, thus maintaining security while enabling fast access.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the physical address parameter by applying encryption. The encrypted physical address retains the functional property of identifying memory locations but loses the property of being derivable or usable for unauthorized access, thereby changing the security characteristics while maintaining access functionality.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If physical addresses are exposed to the host device for direct access, then ease of operation is improved, but reliability is worsened due to unintended modifications

Engineering Contradiction:
Improvedirect access capabilityVSAvoiddata integrity
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The encrypted L2P pointer serves as a mediator that allows the host to operate with address information without having direct access to the actual physical addresses. This prevents the host from making unintended modifications while maintaining ease of operation through simplified access procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary encryption to the physical addresses before they are cached at the host. This preemptive security measure prevents potential harm by ensuring that even if the host attempts unauthorized access or modification, the encrypted addresses cannot be used to derive or access other physical locations.

Inventive Principle:
Principle #9Preliminary anti-action

3Object-affected harmful factors

If encryption is applied to L2P pointers, then security is improved, but device complexity is worsened

Engineering Contradiction:
Improvesecurity protectionVSAvoidcryptographic processing
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The memory system performs the encryption and decryption operations autonomously using stored cryptographic keys. The host device does not need to implement its own encryption logic, as the memory system handles the cryptographic processing automatically, thereby limiting the increase in overall system complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the encryption functionality with the existing L2P pointer management infrastructure. By integrating cryptographic operations into the existing address translation and caching mechanisms, the system avoids duplicating functionality and minimizes the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3814915B1Host side caching security for flash memory
Publication Date: 2024.09.11 MICRON TECHNOLOGY INC
  • EP3814915B1 patent drawingFigure 1
  • EP3814915B1 patent drawingFigure 2
  • EP3814915B1 patent drawingFigure 3

AI summary

Various examples are directed to systems and methods for managing a memory system. The memory system may generate a first encrypted physical address using a first clear physical address. The memory system may generate a first encrypted logical-to-physical (L2P) pointer indicating the first logical address and a first encrypted physical address. The memory system may send the first encrypted L2P pointer to a host device for storage at a host memory.