Non-Volatile Memory Wear Leveling via Key Sanitization
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Solution Overview
Problem
Solid state drives (SSD), flash, and other non-volatile memory devices face premature wear and failure due to significant degradation after a few thousand erasure cycles, making secure data destruction challenging as per federal and state regulations, which existing wear leveling techniques complicate with sophisticated mapping and tracking.
Innovation Solution
A method where data is encrypted, with encryption/decryption keys stored in non-volatile or volatile memory based on classification schemes, allowing keys to be sanitized without erasing the underlying encrypted data, thus limiting erasure commands and prolonging non-volatile memory service life by classifying data for persistence and using appropriate sanitize commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple erasure commands are issued to memory locations to securely mask previous storage states, then data security is improved, but memory device reliability deteriorates due to significant degradation and failure after a few thousand erasure cycles
Solution Approach 1:
The patent segments the data protection mechanism by separating the encryption keys from the encrypted data. Keys are stored in a protected key storage area while data is stored in regular data storage areas. This segmentation allows selective erasure of only the keys rather than the entire data structure, reducing wear on memory cells while maintaining security.
Solution Approach 2:
The patent extracts the essential security element (encryption key) from the data storage system and places it in a separate protected storage area. This extraction enables the key to be independently managed and erased without affecting the underlying encrypted data, thereby reducing the number of erasure cycles required for secure data destruction.
2Duration of action of stationary object
If wear leveling techniques are implemented to track and disseminate erasure commands evenly amongst memory sectors, then memory service life is improved, but device complexity increases due to sophisticated mapping and tracking requirements
Solution Approach 1:
The patent divides the memory system into distinct functional segments: a protected key storage area for storing encryption keys and a data storage area for storing encrypted data. This segmentation simplifies wear leveling by allowing different erasure strategies for different segments, reducing the need for complex cross-segment mapping and tracking.
Solution Approach 2:
The patent applies different quality characteristics to different parts of the memory system. The key storage area is given enhanced protection and durability characteristics through separate management, while the data storage area follows standard wear leveling. This local differentiation simplifies overall system complexity by allowing targeted rather than universal complex management.
Data Source
AI summary
Methods and apparatus teach wear leveling non-volatile memory and secure erasure of data. A computing device receives data to be stored. The data is encrypted, including generation of encryption/decryption key(s). The key(s) are stored in either non-volatile or volatile memory according to a plurality of classification schemes. In a first scheme, key(s) are stored in non-volatile memory and will be retained in the event of a power cycle of the computing device. Otherwise, key(s) stored in volatile memory will be lost upon a power cycle. Upon issuance of a key destruction command, key(s) in the non-volatile memory are sanitized or erased, but the underlying encrypted data need not be erased since no key(s) exist that can recover original content. These techniques limit erasure commands to the non-volatile memory which prolongs its service life. Further embodiments note techniques in imaging devices conducting imaging operations, such as printing or scanning.