ABSTRACT
We consider an UWSN that consists of N sensor nodes. It can be formulated as an undirected graph G E( ,N ), and each sensor si has nbi neighbors. There is a mobile sink that visits the UWSN periodically to collect data. The time interval between the current visit and the previous visit is denoted as T . The sensor si generates data at each round, and the data generated at round r is denoted as Di
r. Once a data Di
r is generated, it is stored locally, and waits until an authorized mobile sink offloads them. Each sensor has the ability to perform one-way hashing and symmetric key encryption. We assume that the mobile sink is a trusted party which cannot be compromised. Additionally, the mobile sink will re-initialize the secret keys and reset the round counters when the mobile sink visits the network.
