1. Kryptotag - Workshop über Kryptographie

Der Report enthält eine Sammlung aller Beiträge der Teilnehmer des 1. Kryptotages am 1. Dezember 2004 in Mannheim

[[alternative]]The Study of Key Agreement in Dynamic Groups without Trusted Third Party

計畫編號：NSC90-2213-E032-017研究期間：200108~200207研究經費：327,000[[sponsorship]]行政院國家科學委員

Heterogeneous Tree Based Authenticated Group Key Transfer Protocol

Message passing from one source to another has become a key for many upcoming technologies. This is already achieved by introduction of topics of KEYS, AUTHENTICATIONS etc. Secret key transfer is being done presently by using mutually trusted key generation centre (KGS). By this selection of session key by which encryption is done for information passing is selected. This paper discusses about the advancement of this technology by extending this service to group instead of a single key. The whole group with authenticated users can access the information. The proposed protocol considers the heterogeneity of the peer resources as QOS factor in key generation phase and shared key mechanism as primary process to achieve security in group key sharing

Group Rekeying Schemes for Secure Group Communication in Wireless Sensor Networks

Wireless sensor networks are promising solutions for many applications. However, wireless sensor nodes suffer from many constraints such as low computation capability, small memory, limited energy resources, and so on. Grouping is an important technique to localize computation and reduce communication overhead in wireless sensor networks. In this paper, we use grouping to refer to the process of combining a set of sensor nodes with similar properties. We propose two centralized group rekeying (CGK) schemes for secure group communication in sensor networks. The lifetime of a group is divided into three phases, i.e., group formation, group maintenance, and group dissolution. We demonstrate how to set up the group and establish the group key in each phase. Our analysis shows that the proposed two schemes are computationally efficient and secure

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