Disk Sanitization via Region-Specific Encryption Keys
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Solution Overview
Problem
Existing disk sanitization methods either sanitize the entire disk or do not allow for granular control over sanitizing specific data blocks, and introduce additional hardware that complicates data access.
Innovation Solution
Implementing a method where data on a disk is encrypted with unique keys for each physical disk region, allowing for selective deletion and sanitization of specific blocks by re-encrypting other blocks with a new key and deleting the original key, without re-encrypting the blocks to be deleted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption is implemented at the disk-wide level to sanitize data, then security is improved, but hardware complexity increases due to the cryptographic interface
Solution Approach 1:
The patent divides the disk into multiple regions, each encrypted with a separate key. This segmentation allows the system to encrypt only specific regions containing sensitive data rather than the entire disk, reducing the complexity of the cryptographic interface while maintaining security for protected data.
2Reliability
If the entire disk is sanitized to protect data, then security is improved, but loss of information occurs because all data including non-sensitive data is affected
Solution Approach 1:
The patent applies encryption selectively to specific disk regions containing sensitive data rather than uniformly across the entire disk. This local quality approach ensures that only the necessary portions of data are protected and can be sanitized independently, preserving access to non-sensitive data while maintaining security for protected regions.
3Reliability
If multiple passes of media overwrite are performed to sanitize data, then security is improved, but loss of time increases due to the repeated writing operations
Solution Approach 1:
The patent replaces the mechanical process of multiple overwrite passes with a cryptographic approach. Instead of repeatedly writing data patterns to the disk, the system encrypts data with a key and then sanitizes by destroying the key. This substitution eliminates the time-consuming multiple pass operations while achieving equivalent or superior sanitization effectiveness.
Data Source
AI summary
A technique for sanitizing data storage devices, such as magnetic disks, is disclosed. Logical data storage units such as files or portions thereof may be individually deleted and sanitized on a disk. A disk is divided into physical disk regions, each comprising one or more blocks. The contents of the disk are encrypted using a separate encryption key for each physical disk region. If a file or other data structure located in a first disk region and encrypted using a first encryption key is to be deleted, the logical portions (i.e., blocks) of that region that do not belong to the file are re-encrypted using a second encryption key, and the first encryption key is deleted.