We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and timebin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We...

Most of the symmetric key authentication schemes deployed today are based on principles introduced by Needham and Schroeder [17] more than twenty years ago. However, since then, the computing environment has evolved from a LAN-based client-server world to include new paradigms, including wide area networks, peer-to-peer networks, mobile ad-hoc networks and ubiquitous computing. Also, there are ...

Chaos theory is the study of dynamical systems that are highly sensitive to initial conditions and exhibit seemingly random behavior. From the perspective of cryptography and information security, randomness generated from entirely deterministic systems is a very appealing property. As such, the application of chaos in modern cryptography has been a topic of much research and debate for over a ...

Most of the symmetric key authentication schemes deployed today are based on principles introduced by Needham and Schroeder [14] more than twenty years ago. However, since then, the computing environment has evolved from a LAN-based client-server world to include new paradigms, including wide area networks, peer-to-peer networks, mobile ad-hoc networks and ubiquitous computing. Also, there are ...

Confidentiality, integrity and authentication are more relevant issues in Ad hoc networks than in wired fixed networks. One way to address these issues is the use of symmetric key cryptography, relying on a secret key shared by all members of the network. But establishing and maintaining such a key (also called the session key) is a non-trivial problem. We show that Group Key Agreement (GKA) pr...

The question often arises of whether or not a given security system requires some form of automated key management, or whether manual keying is sufficient. This memo proposes guidelines for making such decisions. The presumption is that when symmetric cryptographic mechanisms are used in a protocol, then automated key management is generally but not always needed. If manual keying is proposed, ...

The question often arises of whether or not a given security system requires some form of automated key management, or whether manual keying is sufficient. This memo proposes guidelines for making such decisions. The presumption is that when symmetric cryptographic mechanisms are used in a protocol, then automated key management is generally but not always needed. If manual keying is proposed, ...

A mobile ad hoc network (MANET) is a wireless communication network, which does not rely on any centralized management or a pre-existing infrastructure. Various key management authorities distributed over the network, each with a periodically updated share of the secrete key, is usually adopted. Thus many efforts have been made to adapt key management authority’s tasks to the dynamic environmen...