Delay Tolerant Network

A delay tolerant network (DTN) is a store and forward network where end-to-end connectivity is not assumed and where opportunistic links between nodes are used to transfer data. An emerging application of DTNs are rural area DTNs, which provide Internet connectivity to rural areas in developing regions using conventional transportation mediums, like buses. Potential applications of these rural area DTNs are e-governance, telemedicine and citizen journalism. Therefore, security and privacy are critical for DTNs. Traditional cryptographic techniques based on PKI-certified public keys assume continuous network access, which makes these techniques inapplicable to DTNs. We present the first anonymous communication solution for DTNs and introduce a new anonymous authentication protocol as a part of it. Furthermore, we present a security infrastructure for DTNs to provide efficient secure communication based on identity-based cryptography. We show that our solutions have better performance than existing security infrastructures for DTNs.

Epidemic forwarding protocol in Delay Tolerant Networks maximizes successful data delivery probability but at the same time incurs high costs in terms of redundancy of packet copies in the system and energy consumption. Two-hop routing on the other hand minimizes the packet flooding and the energy costs but degrades the delivery probability. This paper presents a framework to achieve a tradeoff between the successful data delivery probability and the energy costs. Each mobile has to decide which routing protocol it wants to use for packet delivering. In such a problem, we consider a non-cooperative game theory approach. We explore the scenario where the source and the destination mobiles are enclosed in two different regions, which are partially overlapped. We study the impact of the proportion of the surface covered by both regions on the Nash equilibrium and price of anarchy. We also design a fully distributed algorithm that can be employed for convergence to the Nash equilibrium. This algorithm does not require any knowledge of some parameter of the system as the number of mobiles or the rate of contacts between mobiles.

Congestion control is an important feature that directly affects network performance. Network congestion may cause loss of data or long delays. Although this problem has been studied extensively in the Internet, the solutions for Internet congestion control do not apply readily to ...

Rural Internet kiosks typically provide weak security guar-antees and therefore cannot support secure web access or transaction-oriented applications such as banking and bill payment. We present a practical, unobtrusive and easy-to-use security architecture for rural Internet kiosks that uses a combination of physical and cryptographic mechanisms to protect user data and kiosk infrastructure. Our contribu-tions include (a) a detailed threat analysis of rural Internet kiosks, (b) a security architecture for rural Internet kiosks that does not require any specialized hardware features in kiosks, and (c) an application-independent and backward-compatible security API for securely sending and receiving data between kiosks and the Internet that can operate over disconnection-tolerant links.

—CubeSats operating in a swarm are characterized by a mix of scheduled intermittent connectivity, high delays, and high failure rates. Each CubeSat is limited in size, usually has low data rates and has a low mass. Consequently, they have limited space for solar panels, and thus limit their available energy. Profitably, CubeSats can function in swarms using inter-CubeSat links as well as ground links. Accordingly, any routing protocols developed for CubeSats must be energy aware. We propose two novel Shortest and Energy Reliable Path (SERP) routing protocols; namely, SERP-Breadth-First Search (SERP-BFS) and SERP-Dijkstra. Both algorithms aim to minimize the overall energy cost and maintain connectivity over time. Both choose shortest paths that have CubeSats energy levels higher than or equal to an energy reliability threshold. We have compared our SERP algorithms with Epidemic algorithm. The results show the outperformance of our proposed algorithms in terms of saving the overall energy cost.