We introduce a new technique for constructing a family of universal hash functions.

Recently, there has been considerable interest in providing "trusted computing platforms" using hardware --- TCPA and Palladium being the most publicly visible examples. In this paper we discuss our experience with building such a platform using a traditional time-sharing operating system executing on XOM --- a processor architecture that provides copy protection and tamper-resistance functions. In XOM, only the processor is trusted; main memory and the operating system are not trusted.

Internet end users and ISPs alike have little control over how packets are routed outside of their own AS, restricting their ability to achieve levels of performance, reliability, and utility that might otherwise be attained. While researchers have proposed a number of source-routing techniques to combat this limitation, there has thus far been no way for independent ASes to ensure that such traffic does not circumvent local traffic policies, nor to accurately determine the correct party to charge for forwarding the traffic. We present Platypus, an authenticated source routing system built around the concept of network capabilities. Network capabilities allow for accountable, fine-grained path selection by cryptographically attesting to policy compliance at each hop along a source route. Capabilities can be composed to construct routes through multiple ASes and can be delegated to third parties. Platypus caters to the needs of both end users and ISPs: users gain the ability to pool their resources and select routes other than the default, while ISPs maintain control over where, when, and whose packets traverse their networks. We describe how Platypus can be used to address several well-known issues in wide-area routing at both the edge and the core, and evaluate its performance, security, and interactions with existing protocols. Our results show that incremental deployment of Platypus can achieve immediate gains.

Active Networks promise greater #exibility than current networks, but threaten safety and securityby virtue of their programmability.

We consider the problem of specifying and verifying cryptographic security protocols for XML web services. The security specification WS-Security describes a range of XML security tokens, such as username tokens, public-key certificates, and digital signature blocks, amounting to a flexible vocabulary for expressing protocols. To describe the syntax of these tokens, we extend the usual XML data model with symbolic representations of cryptographic values. We use predicates on this data model to describe the semantics of security tokens and of sample protocols distributed with the Microsoft WSE implementation of WS-Security. By embedding our data model within Abadi and Fournet’s applied pi calculus, we formulate and prove security properties with respect to the standard Dolev-Yao threat model. Moreover, we informally discuss issues not addressed by the formal model. To the best of our knowledge, this is the first approach to the specification and verification of security protocols based on a faithful account of the XML wire format.

Securing data is more important than ever. As the Internet has become more pervasive, security attacks have

In this paper we describe an efficient algorithm for the management of group-keys. Our algorithm is based on a protocol for secure IP-multicast and is used to manage groupkeys in group-communication systems. Unlike prior work, based on centralized key-servers, our solution is completely distributed and fault-tolerant and its performance is comparable to the centralized solution. 1

Shmatikov z SRI International

RFID (Radio-Frequency Identification) tags are small, inexpensive microchips capable of transmitting unique identifiers wirelessly over a short distance. Thanks to their utility in automating supply-chain logistics, RFID tags promise eventually to supplant the optical barcode as a means of identifying goods.

The Border Gateway Protocol (BGP) is the de facto interdomain routing protocol of the Internet. Although the performance of BGP has been historically acceptable, there are continuing concerns about its ability to meet the needs of the rapidly evolving Internet. A major limitation of BGP is its failure to adequately address security. Recent outages and security analyses clearly indicate that the Internet routing infrastructure is highly vulnerable. Moreover, the design and ubiquity of BGP has frustrated past efforts at securing interdomain routing. This paper considers the vulnerabilities currently existing within interdomain routing and surveys works relating to BGP security. The limitations and advantages of proposed solutions are explored, and the systemic and operational implications of their designs considered. We note that no current solution has yet found an adequate balance between comprehensive security and deployment cost. This work calls not only for the application of ideas described within this paper, but also for further investigation into the problems and solutions of BGP security.