7. Conclusion
This article describes the 4PR protocol, which provides privacy preserving probabilistic prediction-based routing in mobile delay tolerant networks. 4PR is similar to prior prediction-based protocols (e.g., PRoPHET and Bubble), which take advantage of the mobility patterns of nodes to route messages. Our experimental evaluation using a well established community-based mobility model demonstrates that 4PR is comparable to the above noted protocols in terms of performance. Yet, 4PR preserves the privacy of nodes by hiding their individual mobility patterns, whereas the prior protocols do not. The 4PR protocol is the successor of our 3PR protocol, which to the best of our knowledge, was the first protocol to hide the encounter probabilities of nodes in MDTNs. However, 4PR differs fundamentally from 3PR in how messages are exchanged and the protocols that execute in the background. 4PR’s approach gains multiple advantages over 3PR, which include 1) the upper bound of encounter probabilities is not divulged, thus better privacy preservation; 2) private computation of probability requires a single round of computation, whereas private maximum in 3PR required multiple rounds; 3) the probability of at least one node in the community encountering the destination (as in 4PR) is a more accurate measure for routing path prediction than the maximum probability in the community (as in 3PR).
