When a sensor network is deployed in a hostile environment, an adversary may launch such attacks as eavesdropping the communications and compromising sensor nodes. Using the compromised nodes, he may inject false sensing reports or modify the reports sent by other nodes. To defend against these attacks, researchers have proposed symmetric group key-based schemes. In these schemes, however, if a...

We investigate the key management problem for broadcasting applications. Previous work showed that batch rekeying can be more cost-effective than individual rekeying. Under the assumption that every user has probability p of being replaced by a new user during a batch rekeying period, we study the structure of the optimal key trees. Constant bounds on both the branching degree and the subtree s...

Secure group communications are increasingly used in the continuous growth of the Internet applications. In a secure multicast environment, an identical data can be efficiently delivered from a source to multiple receivers within a dynamic group. A simple solution is to encrypt the transmitted data using a symmetric key. However, scalable group rekeying is the main challenge for large and dynam...

Existing ad hoc routing protocols are either unicast or multicast. In this paper we propose a simple extension to the Dynamic Source Routing Protocol (DSR) to cater for group communications where all node addresses are unicast addresses and there is no single multicast address. The proposed sliding window protocol for multiple communications results in significant improvement in total packet de...

In this paper we address the problem of efficiently securing multicast communication in energy constrained wireless ad hoc networks. We show that existing scalable key distribution techniques that rely on logical hierarchies, are energy inefficient. We show that great energy savings can occur when physical location information is considered in the key distribution scheme construction. We also s...

Group key management is a critical task to make the secure multicast application. Group manager is responsible for changing and re-distributing (rekeying) the group key whenever it deems necessary. Many applications will require a security infrastructure that ensures multiple levels of access control for group members and also require very fast rekeying so that it is not disruptive to their per...

We investigate the group key management problem for broadcasting applications. Previous work showed that, in handling key updates, batch rekeying can be more cost-effective than individual rekeying. One model for batch rekeying is to assume that every user has probability p of being replaced by a new user during a batch period with the total number of users unchanged. Under this model, it was r...

Scalable group rekeying is one of the important problems that needs to be addressed in order to support secure multicast communications for large and dynamic groups. One of the challenging issues that arises in scalable group rekeying is the problem of delivering the updated keys to the members of the group in a reliable and timely manner. In this paper, we present a new scalable and reliable k...

Secure group communication is important for applications such as pay-per-view. Other authors have proposed the key tree approach to distribute a shared group key in a way such that the rekeying cost scales linearly with the logarithm of the group size for a join or depart request. The efficiency of the key tree approach depends critically on whether the key tree remains balanced. Periodic rebal...

We have developed a self-healing key distribution scheme for secure multicast group communications for wireless sensor network environment. We present a strategy for securely distributing rekeying messages and specify techniques for joining and leaving a group. Access control in multicast system is usually achieved by encrypting the content using an encryption key, known as the group key (sessi...