Privacy-Preserving Client State Matching via Set Intersection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing systems that monitor a client's state periodically face increased processing burdens due to the need for frequent state transitions and estimation, especially when using oblivious automaton evaluation methods, which disclose privacy concerns.

Innovation Solution

Implementing a privacy-preserving set-intersection protocol that allows a server to determine if a client's state matches a predetermined state without revealing the client's state or the server's automaton, using ciphertext and homomorphic encryption to reduce processing and maintain privacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If oblivious automaton evaluation is used to check client state without disclosure, then privacy is preserved, but processing burden increases significantly over time

Engineering Contradiction:

Improveprivacy preservationVSAvoidprocessing burden

Core Design Contradiction:

Loss of informationVSProductivity

Solution Approach 1:

The server pre-computes and stores encrypted representations of expected states in advance, allowing direct comparison with current client states without re-executing the full automaton evaluation process during periodic monitoring

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of executing the original automaton evaluation process repeatedly, the system creates encrypted copies of the automaton's expected states and compares these with encrypted client states, reducing processing requirements while maintaining privacy

Inventive Principle:

Principle #26Copying

2Measurement precision

If periodic state monitoring is implemented, then state detection is achieved, but client state may be estimated on the server side

Engineering Contradiction:

Improvestate detection accuracyVSAvoidstate privacy

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

An intermediary encryption layer is introduced between the server and client state representations. The server works with encrypted state data throughout the comparison process, ensuring that even though the server performs monitoring, it cannot estimate or infer the actual client state, only verify membership in encrypted form

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9178779B2System for detecting whether client state matches predetermined state

Publication Date: 2015.11.03 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A server connectable to a client able to manage successively transitioned-to states. The server has a set storage unit for storing a set including a predetermined state; a server-side communication unit for communicating with the client using a privacy-preserving set-intersection protocol for detecting whether an element in a mutual set is a common element between mutual sets while preserving privacy; and a determining unit for determining whether the state of the client is included in the set stored by the set storage unit on the basis of ciphertext received in accordance with the privacy-preserving set-intersection protocol. Also provided is an information processing method which is able to manage successively transitioned-to-states.