Securing Causal Relationships in Distributed Systems

In a distributed system, it is often important to detect the causal relationships between events, where event e1 is causally before event e2 if e1 happened before e2 and could possibly have aaected the occurrence of e2. In this paper we argue that it can be essential to security that a process determine, in the face of malicious attack, how two events are causally related. We formulate attacks on causality detection in terms of causal denial and forgery, formalize possible security goals with respect to causality, and present simple algorithms to attain these goals in some situations.