Indexing Encrypted Database Columns via Re-encryption
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Solution Overview
Problem
Creating indexes for encrypted columns is impossible due to the loss of sort ordering and security risks when using traditional methods, resulting in inefficient search performance and the need for full table scans.
Innovation Solution
A method that decrypts encrypted column data, re-encrypts it to maintain sort ordering, and creates indexes using a domain index architecture, allowing for efficient index scans without compromising security, supporting match and range searches independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional indexing methods are used on encrypted columns, then security is maintained, but search performance deteriorates requiring full table scans
Solution Approach 1:
The indexing process is segmented into two separate operations: (1) creating an index on encrypted column data without decryption to maintain security, and (2) creating a separate index on decrypted column data to enable efficient search. This segmentation allows both security and performance requirements to be satisfied simultaneously by using different indexing strategies for different purposes.
Solution Approach 2:
The patent introduces an intermediary mechanism where decrypted column data serves as a mediator between the encrypted storage and the search operation. The decrypted data is used temporarily to create an auxiliary index that enables fast search, while the original encrypted data remains secured. This intermediary approach allows efficient searching without permanently exposing sensitive plaintext data.
2Reliability
If encrypted column data is used directly for indexing, then security is maintained, but sort ordering is lost making indexes meaningless
Solution Approach 1:
The patent applies preliminary action by decrypting the column data before creating the index structure. This preliminary decryption step allows the index to be built on data with preserved sort ordering and meaningful values, while the decryption is performed in advance and the results are used only for index creation, not for storing plaintext.
Solution Approach 2:
The patent changes the encryption parameter state temporarily during index creation by using decrypted data to build the index structure. The decrypted data provides meaningful sort ordering and value relationships necessary for effective indexing. After index creation, the system returns to using encrypted data for storage, thus achieving both index effectiveness and security through parameter state changes.
Data Source
AI summary
The present invention relates to a method of creating indexes so that an index scan can be worked for columns in a database encrypted by means of secrete key cipher algorithm. The method of creating indexes according to the present invention comprises the steps of: re-encrypting to be able to maintain the sort ordering based on a plain text; creating new indexes based on the re-encrypted data; and configuring domain index architecture of encrypted columns so that the created index is used for the index scan in a query statement.