"PoPI Drops Mic: 1,000 Fake Identities Now Require 1,000 Bodies, Sybil Attacks Just Got a Lot More Legwork"

Researchers propose Physical Proof of Proximity (PoPI) to combat Sybil attacks by introducing physical constraints into decentralized systems. PoPI requires nodes to physically react within real-world limits, making attacks more expensive. This mechanism relies on physical signals, such as radio or acoustic signals, to verify proximity. By shifting the attack surface from computation to logistics, PoPI aims to prevent fake identities and artificial consensus influence, particularly in local environments like mesh networks and IoT clusters, where physical presence is already a given, thereby increasing the cost of attacks.