Leaked Age of Information of Preemptive Status Updates Against a Preemptive Eavesdropper

We consider a communication system where preemptive status updates are exchanged with a general objective of data freshness, e.g., for real-Time industrial applications. The transmitter-receiver pair (Alice and Bob) is threatened by an eavesdropper (Eve) that probabilistically intercepts some of the exchanged messages. We model the system performance through the average age of information (AoI), leveraging known results from queueing theory. Alice tunes the status update generation according to a tradeoff between achieving low average AoI at Bob's side, while at the same time keeping Eve with stale leaked information. Unlike existing investigations, we focus on the case where preemption of status updates is performed by both receivers (legitimate or not), so that the considered queues are classified as M/M/1, and we present the performance evaluation to include both freshness and confidentiality considerations.