Public Communication can Facilitate Low-Risk Coordination under Surveillance

TL;DR

This paper demonstrates that public communication, leveraging inherent noise, enables rebels in a surveillance environment to estimate their population fraction with minimal risk of detection, unlike peer-to-peer methods.

Contribution

It introduces a distributed framework showing how public communication patterns facilitate covert estimation of population size under surveillance, highlighting the importance of communication noise.

Findings

Public communication allows covert population estimation.

Peer-to-peer protocols are less efficient or non-covert.

Simple estimation protocols can be executed under extreme surveillance.

Abstract

Consider a sub-population of rebels that wish to initiate a revolution. In order to avoid initializing a failed revolution, rebels would first strive to estimate their relative "power", which is often correlated with their fraction in the population. However, and especially in non-democratic countries, rebels refrain from disclosing themselves. This poses a significant challenge for rebels: estimating their fraction in the population while minimizing the risk of being identified as rebels. This paper introduces a distributed computing framework aiming to study this question. Our main takeaway message is that the communication pattern has a crucial role in achieving such a task. Specifically, we show that relying on the inherent noise in the communication, "public communication", characterized by the fact that each message announced by an individual can be viewed by all its neighbors, allows rebels to estimate their fraction in the population while keeping a negligible risk of each rebel being identified as such. The suggested estimation protocol, inspired by historical events, is extremely simple and can be executed covertly even under extreme conditions of surveillance. Conversely, we show that under peer-to-peer communication, protocols of similar simplicity are either inefficient or non-covert.