Privacy-Preserving Publish-Subscribe Protocol Using Pseudonym Matching
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Solution Overview
Problem
Current publish-subscribe protocols lack effective security and privacy guarantees, particularly in scenarios with honest-but-curious participants, leading to potential privacy violations and inadequate protection of sensitive information.
Innovation Solution
A method involving a server, client, and third party uses pseudonymization and encryption, where the server computes interest and topic pseudonyms using symmetric keys, and the third party determines message delivery based on pseudonym equality, ensuring privacy without revealing subscriber interests to the publisher or other clients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If publish-subscribe protocols are used for data distribution, then message delivery efficiency is improved, but subscriber privacy is violated
Solution Approach 1:
The patent introduces a third party (trusted mediator) that acts as an intermediary between publishers and subscribers. This third party receives published items, computes topic pseudonyms, and selectively forwards items to subscribers based on pseudonym matching without revealing subscriber interests to publishers. The intermediary resolves the contradiction by enabling efficient message distribution while maintaining privacy through cryptographic pseudonymization and selective forwarding.
2Measurement precision
If subscriber interests are revealed to publishers, then message matching accuracy is improved, but privacy protection is worsened
Solution Approach 1:
The patent creates cryptographic copies (pseudonyms) of subscriber interests and topic names. Instead of using actual interest strings that can be read by publishers, the system uses pseudonymized versions that maintain the ability to match interests with topics while being computationally indistinguishable from random strings to anyone without the decryption key. This copying approach preserves matching accuracy while eliminating privacy leaks.
Solution Approach 2:
The patent transforms the parameter representation from plain text interest strings to encrypted pseudonyms. By changing the parameter format from readable interest categories to cryptographic pseudonyms, the system maintains the structural ability to match topics with interests while fundamentally altering the semantic accessibility, preventing publishers from learning actual subscriber preferences.
3Loss of information
If a third party is introduced for privacy protection, then subscriber privacy is improved, but system complexity is worsened
Solution Approach 1:
The third party performs multiple functions: receiving published items, computing topic pseudonyms, matching with subscriber interest pseudonyms, and selectively forwarding items. By consolidating these multiple functions into a single intermediary component, the patent reduces overall system complexity compared to having separate privacy-preserving mechanisms for each function. The universal third party handles all privacy-critical operations centrally.
Data Source
AI summary
A server receives from a client at least one interest pseudonym produced by a double application of a pseudo random function to at least one interest of the client. The server encrypts an item. The server computes at least one intermediate topic pseudonym for at least one topic associated with the item by applying the function to each of the at least one topic associated with the item. The server transmits the at least one intermediate topic pseudonym, the at least one interest pseudonym, and the encrypted item to a third party. The third party may apply the function to the at least one intermediate topic pseudonym to produce at least one topic pseudonym associated with the item and transmit the encrypted item to the client for decryption when one of the at least one masked topic pseudonym is equal to one of the at least one interest pseudonym of the client.