With the increasing growth of electronic communications, it is becoming important to provide a mechanism for enforcing various security policies on network communications. This paper discusses our implementation of several previously proposed protocols that enforce the Bell-LaPadula (1973) security model. We also introduce a new protocol called "Quantized Pump" that offers several advantages, and present experimental results to support our claims.

Security and privacy are growing concerns in the Internet community, due to the Internet's rapid growth and the desire to conduct business over it safely. This desire has led to the advent of several proposals for security standards, such as secure IP, secure HTTP, and the Secure Socket Layer. All of these standards propose using cryptographic protocols such as DES and RSA. Thus, the need to use encryption protocols is increasing. Shared-memory multiprocessors make attractive server platforms, for example as secure World-Wide Web servers. These machines are becoming more common, as shown by recent vendor introductions of platforms such as SGI's Challenge, Sun's SPARCCenter, and DEC's AlphaServer. The spread of these machines is due both to their relative ease of programming and their good price/performance. This paper is an experimental performance study that examines how encryption protocol performance can be improved by using parallelism. We show linear speedup for several different Internet-based cryptographic protocol stack running on a symmetric shared-memory multiprocessor using two different approaches to parallelism.

This paper discusses the necessity of bringing security measures to very complex systems, and some ideas for how to do so.It has long been the hope that we would never reach such a situation -that security technology would eventually succeed in harnessing software technology and bringing it to heel.This has not happened, and it is now time to expand security technology to cope with the seemingly intractable problems of huge heterogeneous systems.The consideration of paradigms from other fields may be useful.This paper hopes to motivate research into a fundamental and difficult problem that affects Internet security today: unpredicted or unintended dynamic behavior that can degrade or destroy the ability of the network to deliver messages.We will argue that the source of the problem is hidden variables that adversely affect composition of network systems at any service level: physical, link, network, transport, application, and even the end-user.

In this paper we develop a general-purpose algorithm that can solve a number of NP-complete problems in time $T = O(2^{n/2} )$ and space $S = O(2^{n/4} )$. The algorithm can be generalized to a family of algorithms whose time and space complexities are related by $T \cdot S^2 = O(2^n )$. The problems it can handle are characterized by a few decomposition axioms; they include knapsack problems, exact satisfiability problems, set covering problems, etc. The new algorithm has considerable cryptanalytic significance, since it can break knapsack-based cryptosystems with up to $n = 100$ generators.

In this paper we develop a general purpose algorithm that can solve a number of NP-complete problems in time T = O(2n/2) and space S = O(2n/4). The algorithm can be generalized to a family of algorithms whose time and space complexities are related by T·S2 = O(2n). The problems it can handle are characterized by a few decomposition axioms, and they include knapsack problems, exact satisfiability problems, set covering problems, etc. The new algorithm has a considerable cryptanalytic significance, since it can break the Merkle-Hellman public key cryptosystem whose recommended size is n = 100.