Security Issues and Solutions in Multicast Environment through Tree based Scheme

Multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires it. Multicasting security is hard because of Open group membership, everyone gets same pack ets, Senders need not be members. We first present taxonomy of mu lticast scenarios on the Internet and point out relevant security concerns. Next we address two major security problems of multicast communication: source authentication, and key revocation. Maintaining authenticity in multicast protocols is a much more complex problem than for unicast, in particular known solutions are prohibitively inefficient in many cases. We present a solution that is reasonable for a range of scenarios. Our approach can be regarded as a midpoi nt between traditional Message Authentication Codes and digital signatures. We also present an improved solution to the key revocation problem

Efficient Key Distribution Schemes for Large Scale Mobile Computing Applications

In emerging networks consisting of large-scale deployments of mobile devices, efficient security mechanisms are required to facilitate cryptographic authentication. While computation and bandwidth overheads are expensive for mobile devices, the cost of storage resources continue to fall at a rapid rate. We propose a simple novel key predistribution scheme, \textit{key subset and symmetric certificates} (KSSC) which can take good advantage of inexpensive storage resources, and has many compelling advantages over other approaches for facilitating ad hoc establishment of pairwise secrets in mobile computing environments. We argue that a combination of KSSC with a variant of an elegant KDS proposed by Leighton and Micali is an appealing choice for securing large scale deployments of mobile devices

Hash Families and Cover-Free Families with Cryptographic Applications

This thesis is focused on hash families and cover-free families and their application to problems in cryptography. We present new necessary conditions for generalized separating hash families, and provide new explicit constructions. We then consider three cryptographic applications of hash families and cover-free families. We provide a stronger de nition of anonymity in the context of shared symmetric key primitives and give a new scheme with improved anonymity properties. Second, we observe that nding the invalid signatures in a set of digital signatures that fails batch veri cation is a group testing problem, then apply and compare many group testing algorithms to solve this problem e ciently. In particular, we apply group testing algorithms based on cover-free families. Finally, we construct a one-time signature scheme based on cover-free families with short signatures

On key storage in secure networks

We consider systems where the keys for encrypting messages are derived from the pairwise intersections of sets of private keys issued to the users. We give improved bounds on the storage requirements of systems of this type for secure communication in a large network

On key storage in secure networks

Abstract: "We consider systems where the keys for encrypting messages are derived from the pairwise intersections of sets of private keys issued to the users. We give improved bounds on the storage requirements of systems of this type for secure communication in a large network.