Memory Purge Encryption Key Erasure
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Solution Overview
Problem
Memory systems face challenges in securely erasing data from Replay Protected Memory Blocks (RPMB) without executing an erase command, particularly when access to encryption keys needs to be revoked to prevent decryption.
Innovation Solution
The memory system overwrites the encryption key stored in the RPMB and then performs a purge operation, transferring valid data to another portion of the memory system, effectively erasing the encryption key by executing an authenticated write and purge operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an erase command is executed to remove data from RPMB, then data security is improved, but the device complexity increases and additional commands are required
Solution Approach 1:
The patent extracts the erase functionality from a separate command into the existing purge operation. By integrating data removal capabilities into the purge command, the system eliminates the need for a dedicated erase command while maintaining security. The purge operation now handles both data transfer and removal functions that were previously requiring separate erase commands.
Solution Approach 2:
The purge operation is enhanced to serve multiple functions: it transfers valid data to new locations and simultaneously removes obsolete data from the RPMB. This multi-functional approach consolidates what would have been separate erase operations into the existing purge workflow, reducing command complexity while improving security.
2Reliability
If encryption keys are stored in RPMB for data encryption, then data security is improved, but the risk of key exposure increases if keys cannot be securely removed
Solution Approach 1:
The system performs preliminary data transfer before key removal. Valid data is copied to new locations in the RPMB first, ensuring data preservation. Only after successful transfer does the system proceed to purge the old key locations, preventing data loss while enabling secure key removal.
Solution Approach 2:
The patent converts the limitation of not having a dedicated erase command into a benefit by enhancing the purge operation. The purge command, originally designed for data management, is extended to handle secure key removal, turning a potential security vulnerability into a strengthened security mechanism.
3Reliability
If a purge operation is performed to transfer data within RPMB, then data security is improved, but the operation time increases
Solution Approach 1:
The system performs partial purging by targeting only the specific portions of the RPMB that contain obsolete encryption keys, rather than purging the entire memory block. This selective approach transfers and removes only the necessary data segments, reducing the overall operation time while maintaining security.
Data Source
AI summary
Methods, systems, and devices for purging data from a memory device are described. A memory system may receive, from a host system, a command to write data to an address storing an encryption key in a first portion of the memory system that is configured to store secure information (e.g., a Replay Protected Memory Block). The encryption key may be configured to encrypt data associated with the host system that is stored in a second portion of the memory system. The memory system may then receive an indication of a purge command from the host system. The memory system may execute the purge command by transferring data from the first portion of the memory system to a third portion of the memory system configured to store secure information and erasing the data from the first portion of the memory system.