Token-Based Mutual Friend Authentication via Private Set Intersection
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Solution Overview
Problem
Existing privacy-preserving mechanisms for identifying shared friends or interests are vulnerable to attacks where malicious users can falsely claim common connections, leading to unjustified trust and privacy risks.
Innovation Solution
A system utilizing an authentication server that generates and manages tokens with encrypted information about user relationships, allowing devices to perform private set intersection to verify the authenticity and closeness of shared friends, using social network data to ensure genuine connections and trust establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If privacy-preserving mechanisms are used to identify shared friends, then user privacy is protected, but the system becomes vulnerable to malicious users who can falsely claim common connections
Solution Approach 1:
The system performs preliminary authentication by requiring both users to possess valid tokens before any privacy-preserving operations occur. The authenticating authority pre-issues tokens to users based on their actual friendship relationships, ensuring that only genuinely connected users can participate in the private set intersection protocol. This preliminary verification step prevents malicious users from falsely claiming connections while maintaining privacy during the actual intersection computation.
Solution Approach 2:
The patent introduces an authenticating authority as an intermediary that issues cryptographic tokens to users. These tokens serve as proof of friendship relationships without revealing the actual friendship data. The intermediary verifies user identities and relationships before enabling private set intersection, thereby ensuring authentication reliability while preserving user privacy through cryptographic abstraction.
2Reliability
If tokens with encrypted relationship information are used, then genuine connections can be verified, but the system complexity increases due to cryptographic operations
Solution Approach 1:
The patent extracts the complex cryptographic verification logic from the user devices and concentrates it in the authenticating authority. The authority handles key generation, token issuance, and verification, while user devices only need to store tokens and participate in simplified private set intersection operations. This extraction reduces device complexity while maintaining reliable connection verification through centralized cryptographic management.
3Adaptability or versatility
If private set intersection is performed to identify common friends, then shared interests can be discovered, but malicious users can still exploit the mechanism to learn about other users' connections
Solution Approach 1:
The system applies preliminary anti-action by requiring tokens that prove genuine friendship relationships before allowing any set intersection operations. The cryptographic tokens embed verification mechanisms that prevent malicious users from participating in or exploiting the private set intersection protocol. This preliminary defensive measure ensures that even if the intersection protocol is executed, malicious users cannot learn about other users' connections because they lack valid tokens to initiate or participate in the protocol.
Data Source
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AI summary
Systems and techniques for authenticating joint friends of users of wireless devices. An authenticating authority delivers a token to a wireless device for each party identified as a friend of a user of the wireless device, such as through relationships in an online social network. Two wireless devices can use information relating to the tokens to determine information relating to joint friends of the users of the devices, such as the identities of joint friends or simply the numbers of joint friends. Tokens can be further refined to allow for analysis that provides information relating to the degree of intimacy of the relationship between a user and a party identified as a friend.