Updatable Private Set Intersection for Arbitrary Inserts and Deletes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing protocols for private set intersection (PSI) do not efficiently support arbitrary insertions and deletions in dynamic settings, leading to inefficiencies and information leakage, particularly in applications like online advertisement statistics where user data needs frequent updates to comply with privacy laws.
Innovation Solution
A framework for updatable PSI is developed using structured encryption (StE) with server-side querying, allowing for constant round protocols with communication and computation complexity that scales linearly with the size of updates and poly-logarithmically with the size of accumulated sets, supporting arbitrary inserts and deletes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PSI protocols are used for dynamic settings with frequent updates, then privacy protection is maintained, but communication and computation complexity scales linearly with the size of the entire input sets leading to inefficiency
Solution Approach 1:
The patent segments the PSI computation into two parts: (1) an offline preprocessing phase that computes cryptographic structures (e.g., accumulators, hash trees) for the entire input set once, and (2) an online update phase that only processes the incremental updates. This segmentation allows the expensive operations to be performed once offline, while updates require only minimal online computation proportional to the update size, not the entire set size.
Solution Approach 2:
The patent performs preliminary actions by precomputing cryptographic structures (such as accumulators, Merkle trees, or other hierarchical structures) during an offline phase before the actual PSI computation is needed. These precomputed structures enable subsequent update operations to be performed efficiently with complexity proportional only to the update size, rather than the entire input set size.
2Adaptability or versatility
If arbitrary deletions are supported in updatable PSI, then flexibility for dynamic data management is improved, but protocol complexity increases compared to insert-only protocols
Solution Approach 1:
The patent introduces an intermediary cryptographic structure (such as an accumulator or hierarchical tree structure) that mediates between the insert and delete operations. This intermediary structure allows both insertions and deletions to be handled uniformly through standardized operations, maintaining protocol complexity at a manageable level while supporting full bidirectional updates.
Solution Approach 2:
The patent changes the parameter representation by using cryptographic accumulators or hierarchical structures where set membership is represented through compact mathematical parameters. This allows insertions and deletions to be performed by updating these parameters efficiently, supporting arbitrary deletions without proportionally increasing protocol complexity.
3Reliability
If PSI is computed repeatedly as sets grow and shrink over time, then up-to-date intersection results are obtained, but communication overhead accumulates linearly with the size of the entire sets
Solution Approach 1:
The patent performs preliminary computation of cryptographic structures during an offline phase, so that repeated PSI computations over time only require exchanging and processing the incremental updates. This eliminates the need to retransmit entire sets in each round, reducing communication overhead to be proportional only to the update size while maintaining accurate intersection results.
Solution Approach 2:
The patent enables continuous update of the PSI result by maintaining cryptographic structures that can be incrementally updated. Instead of performing complete PSI computations from scratch each time, the system continuously updates the intersection by processing only the changes, maintaining reliability while minimizing communication overhead.
Data Source
AI summary
Provided are systems and methods for implementing an updatable private set intersection (UPSI) that supports arbitrary deletions, where one is not known to date. Various embodiments leverage this new UPSI to enable and improve a variety of privacy-preserving applications where PSI is currently employed. For example, various embodiments provide a constant round protocol with worst-case communication and computation complexity that grows linearly in the size of the updates and only poly-logarithmically with the size of the accumulated sets, and provides the first implementation to support arbitrary inserts and deletes for updatable PSI. Any one of these functionalities improve over current solutions.