Key Version Tag for Secure Cloud Storage Erasure
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Solution Overview
Problem
Cloud storage systems face challenges in securely erasing data to repurpose storage allocations between customers, as existing methods like instant secure erase (ISE) can leave randomized data, causing issues with data integrity checks and user data patterns, especially when returning storage units to a new user with known patterns.
Innovation Solution
The method involves inserting a key version tag into an encrypted data stream, which is stored alongside the data. During an ISE operation, the encryption keys and key version tag are changed, and upon reading, the tags are compared. If they mismatch, the data and protection information are replaced with a predetermined pattern, ensuring secure and efficient data erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If instant secure erase (ISE) is used to erase data by changing encryption keys, then data security is improved, but data integrity checks fail and randomized data patterns remain
Solution Approach 1:
A key version tag is introduced as an intermediary element that mediates between the encryption keys and the data integrity verification process. The tag is stored with the data and compared during read operations to determine whether data should be replaced with default patterns, thereby preserving data integrity while maintaining security through key changes
Solution Approach 2:
The system changes the parameter of the key version tag (comparing its value against stored tags) to determine the state of erased data. By monitoring changes in this parameter rather than directly examining data patterns, the system can verify data erasure status without being affected by the randomized patterns left by ISE
2Loss of information
If all data is overwritten with default patterns to maintain user confidence, then data integrity is improved, but time consumption increases
Solution Approach 1:
Instead of completely overwriting all data with default patterns, the system performs a partial action by only replacing data with default patterns when the key version tag mismatch indicates erasure has occurred. This selective approach maintains data integrity while avoiding the time-consuming process of overwriting entire storage units
Solution Approach 2:
The system extracts the key version tag from the encryption key store and compares it with tags stored alongside data. By separating the verification mechanism (tag comparison) from the data itself, the system can efficiently identify and handle only the portions of data that require replacement, rather than processing all data uniformly
Data Source
AI summary
A method includes adding a key version tag to an encryption key store that stores encryption keys. The key version tag is inserted into a data stream. The data stream including the key version tag is written to media. The data in the data stream is erased by scrambling the encryption keys and incrementing the key version tag in the encryption store by a digit. The data stream is replaced with a replacement data pattern when the key version tag stored in the encryption store and the key version tag located in the data stream mismatch.