Sybilproof reputation mechanisms

Source: ACM DOI Authors: Alice Cheng, Eric Friedman Date: 2005

Abstract / key passage

Cheng and Friedman formalize sybilproofness for reputation systems on static graphs and show that there is no symmetric sybilproof reputation function. For nonsymmetric reputations, they describe a general path- and flow-based formulation and give conditions for sybilproofness.

Harness takeaway

This is a clean formal argument against global reputation for multiplayer harnesses. If identities are cheap, a symmetric score can be inflated by spawning linked sybils. Any trust signal that survives should therefore stay directional, observer-relative, and subordinate to provenance, commitments, credentials, and local policy evaluation rather than pretending to be a universal measure of goodness.