Web of Trust (WoT) is a decentralized trust model where reputation and trustworthiness are derived from social graph relationships rather than central authorities.

How It Works

In Nostr, Web of Trust leverages the follow graph (NIP-02 contact lists) and report events to calculate trust scores:

  1. Graph Construction: A directed graph is built from pubkeys, events, and their relationships (follows, mutes, reports)
  2. Weight Assignment: Initial weights are assigned to known-trustworthy pubkeys (e.g., those with verified NIP-05 identifiers)
  3. Iterative Propagation: Trust scores flow through the network using algorithms similar to PageRank
  4. Sybil Resistance: If an attacker creates many fake accounts, the trust passed to them is divided by the number of fakes

Key Properties

  • Decentralized: No central authority determines reputation
  • Personalized: Trust can be calculated from each user’s perspective based on who they follow
  • Sybil-Resistant: Bot farms cannot easily game the system due to trust dilution
  • Composable: Can be applied to spam filtering, content moderation, relay admission, and payment directories

Applications in Nostr

  • Spam Filtering: Relays can use WoT to filter low-trust content
  • Content Discovery: Surface content from accounts trusted by your network
  • Payment Directories: Lightning address lookup with impersonation prevention
  • Relay Policies: WoT relays accept only notes from trusted pubkeys
  • Decentralized Moderation: Communities can curate based on trust scores

Implementations

Several projects implement Web of Trust for Nostr:

  • Nostr.Band Trust Rank: PageRank-style scoring for the network
  • WoT Relays: Relays filtering by social distance
  • DCoSL: Protocol for decentralized reputation systems
  • Noswot: Trust scoring based on follows and reports

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