# How Servers Automatically Connect Users Based on Mutual Friend Lists

> A method for servers to automatically create secure communication links between two users only if they have both added each other to their respective contact or buddy lists.

- **Patent:** US RE45254
- **Original title:** USRE45254E1 - Implicit population of access control lists
- **Owner:** Facebook Inc
- **Granted:** 2014
- **Status:** Active
- **Times cited:** 7
- **Field:** software, telecommunications, ai_ml

## What it does

The patent describes a server-side process that checks if two users have mutually added each other to their contact lists. When both users have the other person on their list, the server interprets this as an implicit trust relationship. Based on this mutual confirmation, the server automatically enables a direct communication pathway, such as a peer-to-peer connection or a virtual private network (VPN), between their devices. This removes the need for manual approval or complex configuration every time two known contacts want to communicate securely.

## What it does NOT cover

- Does not cover connections where only one user has added the other to their list.
- Does not cover manual connection requests that require explicit user-to-user permission prompts.
- Does not cover systems that rely on third-party identity verification rather than user-maintained lists.
- Does not cover local device-to-device discovery that occurs without server-side verification of contact lists.

## The clever bit

It treats the existence of a mutual entry in two separate, private user lists as a cryptographic-like proxy for trust, allowing the network to self-configure connectivity.

## Real-world examples

1. Instant messaging buddy lists
2. Social media direct messaging systems
3. Peer-to-peer file sharing applications
4. Encrypted chat platforms

## Why it matters

This patent addresses the friction of establishing secure, direct communication in early social networking and instant messaging platforms. By automating the 'trust' handshake, it allowed services to scale peer-to-peer features without overwhelming users with security prompts. It represents a shift toward using social graph data to manage network-level connectivity.

## Frequently asked questions

### What does How Servers Automatically Connect Users Based on Mutual Friend Lists cover?

A method for servers to automatically create secure communication links between two users only if they have both added each other to their respective contact or buddy lists.

### Who owns patent US RE45254?

Facebook Inc owns this patent, granted in 2014.

### When does this patent expire?

This patent is expected to expire on November 18, 2034, when the invention enters the public domain.

### What is patent US RE45254 cited by?

This patent has been cited by 7 later patents that build on its ideas.

### What problem does this patent solve?

This patent addresses the friction of establishing secure, direct communication in early social networking and instant messaging platforms. By automating the 'trust' handshake, it allowed services to scale peer-to-peer features without overwhelming users with security prompts. It represents a shift toward using social graph data to manage network-level connectivity.

### What does this patent NOT cover?

Does not cover connections where only one user has added the other to their list.

**Full plain-English explainer:** https://patentbrief.org/patent/us/RE45254/google-docs

**Original patent:** https://patents.google.com/patent/USRE45254

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._