We describe how to combine a minimal Trusted Computing Base (TCB) with polyinstantiated and slightly augmented Commercial Off The Shelf (COTS) software programs in separate Single Level Secure (SLS) partitions to create MultiLevel Secure (MLS) applications. These MLS applications can coordinate fine grained (intra-document) Bell LaPadula (BLP) [6] separation between information at multiple security levels. The untrusted COTS programs in the SLS partitions send at-level file edits as diff transactions to the TCB. The TCB verifies that BLP semantics will be observed and then patches these transactions into its canonical representation of the file. Finally, it releases appropriately filtered versions back to each SLS partition for re-assembly into the COTS program's standard file format. Furthermore, by judiciously restricting how the user can interact with the system the multiple SLS instantiations of the COTS program can be made to appear as if they are a single MLS instantiation. We demonstrate the utility of this approach using Microsoft Word and DokuWiki.

We present a novel technique, known as the non-delegatable authority (NDA), for distributing authority to unconfined subjects in capability systems that prevents them from sharing the exact same authority that they have been given with anyone else. T

This paper describes the security and network architecture of the Annex system, a family of technologies for secure and pervasive communication and information processing that we have developed at the Australian Government's Defence Science and Technology Organisation. Our security architecture is built on top of a distributed object-capability system, which we believe provides an ideal platform for developing very high assurance devices. Our network architecture revolves around next generation networking technologies, including Mobile IPv6 and 802.11i wireless networking, but includes a small number of important extensions to improve security, robustness and mobility in the military context. A particular and unique contribution of our work is the tight integration of our very strong security architecture with next generation networking technologies. To complete the paper we describe our reference implementation of the Annex security and networking architecture, which consists of a number of devices known collectively as the Annex Ensemble.

Summary form only given. We give an overview of two related tools that we have developed to provide more accurate measurement and modelling of the performance of message passing programs and communications on distributed memory parallel computers. MPIBench uses a very precise, globally synchronised clock to measure the performance of MPI communication routines, and can generate probability distributions of communication times, not just the average values produced by other MPI benchmarks. This allows useful insights into MPI communications performance of parallel computers, particularly the effects of network contention. PEVPM provides a simple, fast and accurate technique for performance modelling and prediction of message-passing parallel programs. It uses a virtual parallel machine to simulate the execution of the parallel program. The effects of network contention can be accurately modelled by sampling from the probability distributions generated by MPIBench. These tools are particularly useful on Beowulf clusters with commodity Ethernet networks, where relatively high latencies, network congestion and TCP problems can significantly affect communication performance, and can be difficult to model accurately using other tools. Experiments with example parallel programs demonstrate that PEVPM gives accurate performance predictions on Beowulf clusters. We also show that modelling communication performance using average times rather than sampling from probability distributions can give misleading results, particularly for a large number of processors.