Selective Shredding in Deduplication Storage Systems
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Solution Overview
Problem
In segment deduplication storage systems, efficient data shredding is challenging due to the sharing of segments across multiple files, making it impractical to delete decryption information used for encryption, which is typically smaller than the original data.
Innovation Solution
The solution involves encrypting data segments and destroying the appropriate decryption information by assigning decryption keys based on segment content, using a keyed hash function, and storing these keys in an encrypted database. This process includes removing decryption keys for the file to be shredded and re-encrypting the database with a new master encryption key, making it impractical to retrieve the file.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If decryption information is destroyed to achieve fast shredding, then shredding speed is improved, but the ability to securely shred shared segments is worsened
Solution Approach 1:
The patent segments the decryption information by assigning unique decryption keys to each segment rather than using a single master key. This allows selective destruction of decryption keys for specific segments without affecting other segments, enabling secure shredding of individual files while maintaining the ability to quickly destroy only the necessary decryption information.
Solution Approach 2:
The patent applies local quality by making each segment have its own decryption key, so that shredding operations can be applied locally to specific segments without affecting the entire dataset. This allows the system to destroy decryption information for only the segments that need to be shredded, improving both speed and security.
2Quantity of substance
If segments are shared across multiple files to improve storage efficiency, then storage efficiency is improved, but the complexity of selective shredding is worsened
Solution Approach 1:
The patent divides the shredding operation into segment-level operations, where each segment can be independently identified and shredded. By segmenting both the storage structure and the shredding process, the system maintains storage efficiency through segment sharing while simplifying the shredding complexity through targeted key destruction.
Solution Approach 2:
The patent introduces decryption keys as intermediary elements that mediate between segments and files. Each segment is encrypted with a unique key, and files are associated with specific keys. This intermediary structure allows the system to efficiently share segments across multiple files while enabling selective shredding by simply destroying the appropriate key without needing to manipulate the actual segment data.
Data Source
AI summary
Making a target file impractical to be retrieved comprises decrypting a directory manager file using a first directory manager file key. The directory manager file includes an encryption key for a segment that is used when reconstructing a target file. The directory manager file is modified by deleting a reference to the target file. The reference includes a file encryption key. Retrieving the target file is made impractical by the deletion of the reference to the target file in the directory manager file. The modified directory manager file is encrypted using a second directory manager file key.