An Active Attack on a Multiparty Key Exchange Protocol

TL;DR

This paper presents an active attack on a previously secure multiparty key exchange protocol, exploiting malicious control over communication channels during the key exchange process.

Contribution

The paper introduces a novel active attack method that compromises the security of a known multiparty key exchange protocol under specific malicious conditions.

Findings

Active attack successfully breaches the protocol's security

Attack requires control over communication of last two users

Protocol is vulnerable during the key exchange phase

Abstract

The multiparty key exchange introduced in Steiner et al.\@ and presented in more general form by the authors is known to be secure against passive attacks. In this paper, an active attack is presented assuming malicious control of the communications of the last two users for the duration of only the key exchange.