NCR-9508528, University of Wisconsin-Milwaukee, Multi-Sender and Multi-Receiver Network Security, PI-Yvo Desmedt: State of the art network security is based on end-to-end encryption and link encryption. In many security operations there are multiple senders and/or receivers. The straightforward application of link or end-to-end oriented techniques to network security implies either that the required bandwidth increases dramatically or that a terrible key management problem is created. Several multi-sender-multi-receiver cryptosystems have been presented previously. One of these schemes guarantees unconditionally the authenticity of broadcast. Several schemes have been developed in which the power to use a cryptosystem is shared non-interactively without the need for having a trusted party. The schemes protect against insiders conspiring with outsiders. Some of the schemes allow a majority of co-senders to co-sign a document non-interactively without enabling a minority to use the occasion to substitute a fraudulent message. Others allow a majority of co-receivers to co-decrypt a ciphertext. A minority cannot use such a decryption process to decrypt another ciphertext. Different schemes allow for different security requirements (e.g. heuristic and proven secure). Having demonstrated previously the feasibility to achieve several of the original objectives refinements are studied here including (1) how one can detect and correct internal disrupters who jam the co-production of a signature by sending erroneous data (and simi lar problems will be addressed for the joint description of ciphertext), (2) how to trace those who co-signed, in general those who used their share of cryptographic power, and (3) how to improve previously developed schemes and study bounds on performance. ***************************************************************************** Aubrey M. Bush Program Director, Acting Deputy Divison Director Division of Networking and Communications Research and Infrastructure National Science Foundation
