Updatable Private Set Intersection with Encrypted Residual Subsets
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Solution Overview
Problem
Existing PSI protocols are resource-intensive when sets are updated frequently, requiring each party to process and compare their entire sets, leading to significant computational and communication overhead.
Innovation Solution
Implement updatable PSI protocols that allow parties to determine the updated intersection by iteratively processing partial intersections and using encrypted binary tree structures, reducing the need to re-compute the entire sets each time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing PSI protocols process entire sets to determine intersection, then privacy protection is maintained, but computational and communication overhead becomes significant
Solution Approach 1:
The patent segments the sets into residual subsets (elements not in intersection) and new subsets (elements added to sets). Instead of processing entire sets, the protocol processes only the residual subsets to determine updates to the intersection. This segmentation allows privacy protection to be maintained while significantly reducing computational and communication overhead when sets are updated.
2Measurement precision
If PSI protocols re-process entire sets on updates, then intersection accuracy is maintained, but computation time scales linearly with total set size
Solution Approach 1:
The patent performs preliminary actions by maintaining residual subsets that track elements not in the intersection. When updates occur, the protocol uses these pre-maintained residual subsets to quickly determine the updated intersection without re-processing the entire original sets. This preliminary organization of data enables fast updates while maintaining intersection accuracy.
3Reliability
If parties exchange encrypted versions of entire sets, then privacy is preserved, but communication cost increases linearly with set size
Solution Approach 1:
The patent extracts only the necessary information for determining the updated intersection by working with residual subsets rather than entire sets. The protocol exchanges encrypted representations of only the residual subsets, which contain the information needed to compute intersection updates. This extraction significantly reduces communication cost while preserving privacy, as only the minimal necessary data is transmitted.
Data Source
AI summary
“Updatable” private set intersection (PSI) protocols allow parties that each have an updatable private set to determine the intersection of their sets after an update without the need to compare each element of each set and without compromising privacy. In some protocols, a first party can determine an update to the intersection by determining an intersection of elements that were previously in the first party's set with elements that were added to the second party's set and determining an intersection of elements that were added to the first party's set with elements that are in the second party's (updated) set. In some protocols, both parties can determine the updated intersection.