Privacy-preserving logical vector clocks using secure computation techniques

Abstract

Systems of logical clocks are commonly found in distributed systems for establishing causality between events occurring in concurrent communicating processes. Vector clocks are a popular type of logical clocks which require processes to attach to each message a logical timestamp that contains information about the sender process's view of the state of the distributed computation at the time of message sending. Causality between two events can then be determined by comparing their two logical timestamps. However, by doing so, processes leak potentially sensitive information about the advancement of their computation and the computations performed by the processes they communicate with. The contribution presented in this paper is a protocol, based on secure computation techniques, which preserves the privacy of each process's local logical clock while being strictly equivalent to regular vector clocks.