In security protocol analysis, the traditional choice to consider a single Dolev–Yao attacker is supported by the fact that models with multiple collaborating Dolev–Yao attackers are reducible to models with one Dolev–Yao attacker. In this paper, we take a fundamentally different approach and investigate the case of multiple non-collaborating attackers. We formalize a framework for multi-attacker scenarios and show, through a detailed case study, that concurrent competitive attacks can interfere with each other. It is then possible to exploit interference to provide a form of defense to vulnerable protocols.
