Storage Device Secure Delete via Key Switching
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Solution Overview
Problem
Existing storage devices do not adequately ensure the security of data deletion operations, as deleted data may not be physically erased and can be retrieved by malicious users.
Innovation Solution
A storage device is designed to allocate a secure region and a user region, where data is encrypted using different keys. During a secure delete operation, valid data is decrypted using an old key, re-encrypted with a new key, and stored in another block, while the old key is deleted, ensuring that the deleted data cannot be recovered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data is deleted by removing mapping relationships only, then storage space is freed and operation is simple, but data can still be retrieved by malicious users compromising security
Solution Approach 1:
The patent extracts the encryption key from the storage system to achieve secure deletion. By removing the key rather than just the data mapping, the system ensures that deleted data becomes unrecoverable while maintaining operational simplicity through automated key management
Solution Approach 2:
The patent changes the encryption parameter by switching encryption keys. When data is marked for deletion, a new encryption key is generated and applied to remaining data, rendering previously stored encrypted data unreadable and effectively securing the deletion process
2Reliability
If encryption keys are retained for data recovery, then data accessibility is maintained, but security of deleted data is compromised
Solution Approach 1:
The patent performs preliminary key deletion before data can be accessed. By deleting the encryption key as part of the deletion process, the system proactively prevents any future recovery attempts, ensuring deleted data remains unrecoverable while maintaining ease of operation through automated key management
3Reliability
If all data in a data block is physically erased to ensure security, then data deletion security is improved, but valid data in the same block is lost and storage efficiency decreases
Solution Approach 1:
The patent segments the data block into individual data units that can be independently encrypted and decrypted. This allows selective deletion where only specific data units are affected by key changes while other valid data units remain accessible, maintaining storage efficiency while achieving secure deletion
Solution Approach 2:
The patent applies different encryption keys to different data units within the same data block. This local differentiation allows the system to secure specific deleted data by changing its encryption key while leaving other valid data in the same block unaffected and accessible, preserving storage efficiency
Data Source
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AI summary
Disclosed is a method of operating a storage device which communicates with a host device. The method includes allocating a secure region and a user region, storing first data encrypted by using a first encryption key in a first data block of the secure region, receiving a first request indicating a first secure delete operation of the first data from the host device, decrypting at least one valid data of the first data block by using the first encryption key based on the first request, wherein the at least one valid data do not include the first data, encrypting the decrypted at least one valid data by using a second encryption key different from the first encryption key, storing the encrypted at least one valid data in a second data block of the secure region, and deleting the first encryption key.