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Multicast communication is becoming the basis for a growing number of applications. It is therefore critical to provide sound security mechanisms for multicast communication. Yet, existing security protocols for multicast offer only partial solutions. We first present a taxonomy of multicast scenarios on the Internet and point out relevant security(More)
Ordinary digital signatures have an inherent weakness: if the secret key is leaked, then all signatures, even the ones generated before the leak, are no longer trustworthy. Forward-secure digital signatures were recently proposed to address this weakness: they ensure that past signatures remain secure even if the current secret key is leaked. We propose the(More)
We propose a new notion of signer-base intrusion-resilient (SiBIR) signatures, which generalizes and improves upon both forward-secure [And97, BM99] and key-insulated [DKXY02] signature schemes. Specifically, as in the prior notions, time is divided into predefined time periods (e.g., days); each signature includes the number of the time period in which it(More)
We consider the problem of electing a leader on a ring of nameless processors by de terministic and self stabilizing protocols A processor can read the state of its neighbors and its own state to determine if it is enabled A central demon scheduler picks an enabled processor to make an atomic move In an atomic move the processor changes to a new state which(More)
We study the limitations of steganography when the sender is not using any properties of the underlying channel beyond its entropy and the ability to sample from it. On the negative side, we show that the number of samples the sender must obtain from the channel is exponential in the rate of the stegosystem. On the positive side, we present the first(More)
Signer-Base Intrusion-Resilient (SiBIR) signature schemes were defined in [IR02]. In this model, as in the case of forward security, time is divided into predefined time periods (e.g., days); each signature includes the number of the time period in which it was generated; while the public key remains the same, the secret keys evolve with time. In addition,(More)
We propose a new notion of intrusion-resilient signature schemes, which generalizes and improves upon both forward-secure [And97, BM99] and key-insulated [DKXY02] signature schemes. Specifically, similarly to the prior notions, time is divided into predefined time periods (e.g., days) so that a signature includes the time period number, changing which(More)
Vertex and edge connectivity are special cases of mixed connectivity, in which all edges and a specified set of vertices play a similar role. Certificates of k-connectivity for a graph are obtained by removing a subset of its edges, while preserving its connectivity up to k. We unify the previous work on connectivity certificates and extend it to handle(More)
We survey the development of forward security and relate it to other concepts and trends in modern cryptography. Ordinary digital signatures have an inherent weakness: if the secret key is leaked, then all signatures, even the ones generated before the leak, are no longer trustworthy. Forward-secure digital signatures were proposed to address this weakness:(More)