249,753 research outputs found
Key Agreement for Large-Scale Dynamic Peer Group
Many applications in distributed computing systems,such as IP telephony, teleconferencing, collaborative workspaces,interactive chats and multi-user games, involve dynamic peergroups. In order to secure communications in dynamic peergroups, group key agreement protocols are needed. In this paper,we come up with a new group key agreement protocol, composedof a basic protocol and a dynamic protocol, for large-scaledynamic peer groups. Our protocols are natural extensions ofone round tripartite Diffie-Hellman key agreement protocol. Inview of it, our protocols are believed to be more efficient thanthose group key agreement protocols built on two-party Diffie-Hellman key agreement protocol. In addition, our protocols havethe properties of group key secrecy, forward and backwardsecrecy, and key independence
Secure group key agreement
As a result of the increased popularity of group-oriented applications and protocols, group communication occurs in many different settings: from network multicasting to application layer tele- and video-conferencing. Regardless of the application environment, security services are necessary to provide communication privacy and integrity. This thesis considers the problem of key management in a special class of groups, namely dynamic peer groups. Key management, especially in a group setting, is the corner stone for all other security services. Dynamic peer groups require not only initial key agreement but also auxiliary key agreement operations such as member addition, member exclusion and group fusion. We discuss all group key agreement operations and present a concrete protocol suite, CLIQUES, which offers all of these operations. By providing the first formal model for group key establishment and investigating carefully the underlying cryptographic assumptions as well as their relations, we formally prove the security of a subset of the protocols based on the security of the Decisional Diffie-Hellman assumption; achieving as a side-effect the first provably secure group key agreement protocolMit der Verbreitung offener Netze, insbesondere des Internets, fand auch
die Gruppenkommunikation eine rasante Verbreitung. Eine Vielzahl heutiger
Protokolle sind gruppen-orientiert: angefangen bei Multicast-Diensten
in der Netzwerkschicht bis hin zu Videokonferenzsystemen auf der Anwendungsschicht. Alle diese Dienste haben Sicherheitsanforderungen wie Vertraulichkeit und IntegritĂ€t zu erfĂŒllen, die den Einsatz kryptographischer
Techniken und die VerfĂŒgbarkeit gemeinsamer kryptographischen SchlĂŒssel
oft unumgÀnglich machen.
In der folgenden Doktorarbeit betrachte ich dieses grundlegendste Problem
der Gruppenkommunikation, nĂ€mlich das SchlĂŒsselmanagement, fĂŒr dynamische Gruppen, die sogenannten "Dynamic Peer-Groups';. Die Dynamik dieser Gruppen erfordert nicht nur initialen SchlĂŒsselaustausch innerhalb einer Gruppe sondern auch sichere und effiziente Verfahren fĂŒr die Aufnahme neuer und den AusschluĂ alter Gruppenmitglieder. Ich diskutiere alle dafĂŒr notwendigen Dienste und prĂ€sentiere CLIQUES, eine Familie von Protokollen, die diese Dienste implementiert. Ich gebe erstmalig eine formale Definition fĂŒ sicheres Gruppen-SchlĂŒsselmanagement und beweise die Sicherheit der genannten Protokolle basierend auf einer kryptographischen Standardannahme, der "Decisional Diffie-Hellman'; Annahme. Diese Sicherheitsbetrachtung wird durch eine detaillierte Untersuchung dieser Annahme und ihrer Relation zu verwandten Annahmen abgeschlossen
Secure group key agreement
As a result of the increased popularity of group-oriented applications and protocols, group communication occurs in many different settings: from network multicasting to application layer tele- and video-conferencing. Regardless of the application environment, security services are necessary to provide communication privacy and integrity. This thesis considers the problem of key management in a special class of groups, namely dynamic peer groups. Key management, especially in a group setting, is the corner stone for all other security services. Dynamic peer groups require not only initial key agreement but also auxiliary key agreement operations such as member addition, member exclusion and group fusion. We discuss all group key agreement operations and present a concrete protocol suite, CLIQUES, which offers all of these operations. By providing the first formal model for group key establishment and investigating carefully the underlying cryptographic assumptions as well as their relations, we formally prove the security of a subset of the protocols based on the security of the Decisional Diffie-Hellman assumption; achieving as a side-effect the first provably secure group key agreement protocolMit der Verbreitung offener Netze, insbesondere des Internets, fand auch
die Gruppenkommunikation eine rasante Verbreitung. Eine Vielzahl heutiger
Protokolle sind gruppen-orientiert: angefangen bei Multicast-Diensten
in der Netzwerkschicht bis hin zu Videokonferenzsystemen auf der Anwendungsschicht. Alle diese Dienste haben Sicherheitsanforderungen wie Vertraulichkeit und IntegritĂ€t zu erfĂŒllen, die den Einsatz kryptographischer
Techniken und die VerfĂŒgbarkeit gemeinsamer kryptographischen SchlĂŒssel
oft unumgÀnglich machen.
In der folgenden Doktorarbeit betrachte ich dieses grundlegendste Problem
der Gruppenkommunikation, nĂ€mlich das SchlĂŒsselmanagement, fĂŒr dynamische Gruppen, die sogenannten "Dynamic Peer-Groups\u27;. Die Dynamik dieser Gruppen erfordert nicht nur initialen SchlĂŒsselaustausch innerhalb einer Gruppe sondern auch sichere und effiziente Verfahren fĂŒr die Aufnahme neuer und den AusschluĂ alter Gruppenmitglieder. Ich diskutiere alle dafĂŒr notwendigen Dienste und prĂ€sentiere CLIQUES, eine Familie von Protokollen, die diese Dienste implementiert. Ich gebe erstmalig eine formale Definition fĂŒ sicheres Gruppen-SchlĂŒsselmanagement und beweise die Sicherheit der genannten Protokolle basierend auf einer kryptographischen Standardannahme, der "Decisional Diffie-Hellman\u27; Annahme. Diese Sicherheitsbetrachtung wird durch eine detaillierte Untersuchung dieser Annahme und ihrer Relation zu verwandten Annahmen abgeschlossen
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Efficient group key agreement & recovery in ad hoc networks
Ad hoc networks are dynamic peer-to-peer wireless networks composed of a collection of nodes which employ wireless transmission methods in a self-organized way without relying on fixed infrastructure or predetermined connectivity. Such networks pose great challenges in group communication. In this paper, we propose an efficient group key agreement and recovery mechanism based on key escrow systems for ad hoc networks. Nodes randomly change their operation and perform authentication services for specific groups
Identifying diferent scenarios for group access control in distributed environments
Open Access Documen
An Active Attack on a Multiparty Key Exchange Protocol
The multiparty key exchange introduced in Steiner et al.\@ and presented in
more general form by the authors is known to be secure against passive attacks.
In this paper, an active attack is presented assuming malicious control of the
communications of the last two users for the duration of only the key exchange
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