Abstract. Rampart is a toolkit of protocols to facilitate the development ofhigh-integrity services, i.e., distributed services that retain their availability and correctness despite the malicious penetration of some component servers by an attacker. At the core of Rampart are new protocols that solve several basic problems in distributed computing, including asynchronous group membership, reliable multicast (Byzantine agreement), and atomic multicast. Using these protocols, Rampart supports the development of high-integrity services via the technique of state machine replication, and also extends this technique with a new approach to server output voting. In this paper we give a brief overview of Rampart, focusing primarily on its protocol architecture. We also sketch its performance in our prototype implementation and ongoing work. 1

In this note we address the short-term security o ered by the use of a 512-bit RSA modulus. Following recent tremendous improvements to the practicality of the generalized number eld sieve, it must be expected that by the end of next year, a 512-bit RSA number will have been factored. However, for those elded systems which use 512-bit RSA, what are the implications? Some systems may well continue using 512-bit RSA long after one particular 512-bit RSA number has been factored. In this note, we present data which might provide answers to questions about the continuing use of a 512-bit RSA modulus.

Abstract: Security of public key cryptography is steadily threatened by advancements in algorithmics and computing power. In this work we propose a novel approach to long-term secure key exchange based on security assumptions that are independent of strong complexity assumptions. We present a key propagation scheme that sets up a network of distributed keys. Whenever two parties meet, they exchange new keys (e.g. using near field communication) and pass on all keys received so far. This establishes a dense key network growing and spreading with each meeting of protocol participants. Even two parties that have never met in person can use this network to obtain a common secret. A notable security feature of our scheme is the anonymity of the established keys, making it hard for an adversary to track movements of protocol participants. Keywords: Key Propagation, Mobile Ad-Hoc Networks, Key Exchange. 1