Memory System Encryption with Physical Address for SSD
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Solution Overview
Problem
Conventional solid state drives (SSDs) using NAND flash memory require redundant address translation tables on both the host and SSD, leading to high memory resource usage and degraded I/O performance due to double address translation, as well as increased data write amounts that shorten SSD lifespan through write amplification.
Innovation Solution
The proposed solution involves a memory system where the flash storage device executes encryption and decryption operations using both an encryption key and physical address, allowing direct control of data placement and sharing of the flash translation layer (FTL) between the host and SSD, thereby eliminating the need for redundant address translation tables and reducing write amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If redundant address translation tables are maintained on both host and SSD, then data placement control is improved, but memory resource usage increases and I/O performance degrades
Solution Approach 1:
The patent extracts the address translation function from the host side and consolidates it solely on the SSD side. The host issues simple logical address requests, while the SSD's FTL handles all address translation to physical addresses internally, eliminating the need for redundant address translation tables on the host and reducing overall memory resource consumption.
Solution Approach 2:
The patent merges the address translation functionality into a single FTL module within the SSD, combining address management, translation, and data placement control functions. This consolidation eliminates duplicate address tables across host and SSD, reducing memory resource usage while maintaining full data placement control capability.
2Ease of operation
If redundant address translation tables are maintained on both host and SSD, then data placement control is improved, but I/O performance degrades due to double address translation
Solution Approach 1:
The patent removes the address translation operation from the host side, extracting it as a separate function that resides exclusively in the SSD's FTL. This eliminates the double address translation process where both host and SSD previously performed translation, thereby improving I/O performance while the FTL continues to provide comprehensive data placement control.
3Reliability
If encryption is performed using only data content, then security is improved, but identical data produces same encryption results enabling pattern recognition
Solution Approach 1:
The patent introduces asymmetry into the encryption process by combining the data content with the physical address as encryption inputs. Even when the same data is encrypted multiple times, different physical addresses produce different ciphertext outputs. This asymmetric encryption approach maintains security while preventing pattern recognition that would occur with content-only encryption.
Solution Approach 2:
The patent changes the encryption parameters from solely data content to a combination of data content and physical address. This parameter modification ensures that identical data encrypted at different physical locations produces different encryption results, enhancing security by eliminating patterns while maintaining the reliability of the encryption system.
4Adaptability or versatility
If write amplification occurs due to redundant data writes, then data placement flexibility is improved, but SSD lifespan shortens
Solution Approach 1:
The patent implements feedback mechanisms within the FTL that monitor write operations and optimize data placement decisions. By tracking write patterns and physical address allocations, the FTL can make intelligent decisions about data placement that minimize redundant writes and write amplification, thereby extending SSD lifespan while maintaining data placement flexibility through adaptive management.
Data Source
AI summary
According to one embodiment, when data is to be written to a first physical storage location that is designated by a first physical address, a memory system encrypts the data with the first physical address and a first encryption key, and writes the encrypted data to the first physical storage location. When the encrypted data is to be copied to a second physical storage location, the memory system decrypts the encrypted data with the first physical address and the first encryption key, and re-encrypts the decrypted data with a second encryption key and a copy destination physical address indicative of the second physical storage location.