# Centralized vs Decentralized Multi-Agent Guesswork

## TL;DR

This paper analyzes how multiple agents, both coordinated and uncoordinated, perform guesswork attacks on a secret, showing that collaboration reduces the exponential growth rate of required guesses, with implications for security strategies.

## Contribution

It introduces the concept of guesswork exponent in multi-agent attacks and compares centralized versus decentralized strategies, revealing the benefits of coordination.

## Key findings

- Multi-agent attacks lower the guesswork exponent compared to single-agent attacks.
- Decentralized multi-agent guesswork is less efficient than coordinated attacks.
- Coordination among two agents further reduces the guesswork exponent.

## Abstract

We study a notion of guesswork, where multiple agents intend to launch a coordinated brute-force attack to find a single binary secret string, and each agent has access to side information generated through either a BEC or a BSC. The average number of trials required to find the secret string grows exponentially with the length of the string, and the rate of the growth is called the guesswork exponent. We compute the guesswork exponent for several multi-agent attacks. We show that a multi-agent attack reduces the guesswork exponent compared to a single agent, even when the agents do not exchange information to coordinate their attack, and try to individually guess the secret string using a predetermined scheme in a decentralized fashion. Further, we show that the guesswork exponent of two agents who do coordinate their attack is strictly smaller than that of any finite number of agents individually performing decentralized guesswork.