Encrypted Database Partial Linking via Range Search Keys
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing encrypted database systems face the challenge of linking between tables without decrypting data, while preventing unnecessary data leakage, as they often link rows beyond the intended result, exposing correlated information.
Innovation Solution
An encrypted database system that uses a client terminal and server with a partial link function, employing a secret key to encrypt data and generate range search keys for linking rows within specific value ranges, ensuring only necessary data is linked and kept encrypted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional linking methods are used on encrypted tables, then data privacy is protected, but the ability to perform selective linking based on value ranges is lost
Solution Approach 1:
The patent segments the linking operation into two distinct phases: first, range-based filtering using encrypted comparison operators (>=, <=, >, <) on the a-th column to identify candidate rows; second, equality-based joining on encrypted b-th and c-th columns for the filtered rows. This segmentation allows selective linking based on value ranges while maintaining encryption throughout, resolving the contradiction between adaptability and information loss.
Solution Approach 2:
The patent introduces encrypted comparison operators and encrypted equality operators as intermediaries that enable range-based filtering and joining operations without decrypting the data. These operators act as mediators between the encrypted data and the linking operation, allowing the system to perform selective linking while preserving data privacy through homomorphic encryption properties.
2Productivity
If all rows are linked between encrypted tables, then complete linking is achieved, but unnecessary data leakage occurs
Solution Approach 1:
The patent implements partial linking by first filtering rows based on range conditions (a-th column between p and q) and then performing equality-based joining only on the filtered subset. This partial action approach links only the necessary rows that meet the specified criteria, avoiding the harmful effect of linking all rows which would cause unnecessary data leakage while still achieving productive linking of relevant data.
3Measurement precision
If decryption is performed before linking, then linking accuracy is improved, but security is compromised
Solution Approach 1:
The patent replaces the mechanical decryption step with cryptographic operations. Instead of decrypting data to perform comparisons and joins, the system uses encrypted comparison operators and encrypted equality operators that work directly on ciphertext. This substitution maintains linking accuracy through proper cryptographic comparison while preserving security by eliminating the decryption step entirely.
Data Source
AI summary
This encrypted database system is constituted by the connection of client terminal, which encrypts and outputs a first table having row a and row b data that has been input and a second table having row c data by means of a secret key stored in advance and sends a partial connection command that connects the row b and row c as a key for data in which the value for row a is greater than or equal to p and less than q in this table to the outside with a range search key generated from the secret key, and an encrypted database server, which receives and records the encrypted first and second tables, extracts data for each in which the values for row a from the encrypted first and second tables are greater than or equal to p and less than q using the range search key, and connects and returns row b and row c for this extracted data as a key.