Maintaining the Security and Availability of a Stream of Time-Dependent Secret Information in an Ad-Hoc Network.

Abstract

In this thesis we present a system called Ad Hoc Security for maintaining the security and availability of a stream of time-dependent secret data in an ad-hoc network. Time-dependence refers to how each piece of data is only useful during a unique time window. The goal is to determine the effectiveness of the Ad Hoc Security system for distributing and securing secret information in a mobile ad-hoc network under a variety of connectivity scenarios, with different sets of behavior parameters. Ad Hoc Security makes use of threshold cryptography for both decryption of the data as well as authentication of the participating devices. It is implemented and tested in the network simulator called ns3. The results of these tests are compared to show how different connectivity scenarios and behavior parameters affect the overall performance and security. The tests demonstrate its ability to adaptively shift between higher security and higher reliability based on its surroundings. Ad Hoc Security is compared to a similar, theoretical system that is tuned for perfect reliability at the cost of security. Compared to the perfectly reliable system, Ad Hoc Security consistently has half the vulnerable time and half as much decryption material saved with a minimum (and often avoidable) decrease in reliability. Most of the unreliability was from rapid, random group separation that the system could not predict or adapt to fast enough. At the end we also present three potential ways of improving reliability.