OceanStore is a utility infrastructure designed to span the globe and provide continuous access to persistent information. Since this infrastructure is comprised of untrusted servers, data is protected through redundancy and cryptographic techniques. To improve performance, data is allowed to be cached anywhere, anytime. Additionally, monitoring of usage patterns allows adaptation to regional outages and denial of service attacks; monitoring also enhances performance through pro-active movement of data. A prototype implementation is currently under development. 1

We identify the trust management problem as a distinct and important component of security in network services. Aspects of the trust management problem include formulating security policies and security credentials, determining whether particular sets of credentials satisfy the relevant policies, and deferring trust to third parties. Existing systems that support security in networked applications, including X.509 and PGP, address only narrow subsets of the overall trust management problem and often do so in a manner that is appropriate to only one application. This paper presents a comprehensive approach to trust management, based on a simple language for specifying trusted actions and trust relationships. It also describes a prototype implementation of a new trust management system, called PolicyMaker, that will facilitate the development of security features in a wide range of network services. 1. Introduction The importance of cryptographic techniques in a wide range of network s...

We present principles for the design of cryptographic protocols. The principles are neither necessary nor sufficient for correctness. They are however helpful, in that adherence to them would have avoided a considerable number of published errors. Our principles are informal guidelines. They complement formal methods, but do not assume them. In order to demonstrate the actual applicability of these guidelines, we discuss some instructive examples from the literature. 1

We present a flexible architecture for trusted computing, called Terra, that allows applications with a wide range of security requirements to run simultaneously on commodity hardware. Applications on Terra enjoy the semantics of running on a separate, dedicated, tamper-resistant hardware platform, while retaining the ability to run side-by-side with normal applications on a generalpurpose computing platform. Terra achieves this synthesis by use of a trusted virtual machine monitor (TVMM) that partitions a tamper-resistant hardware platform into multiple, isolated virtual machines (VM), providing the appearance of multiple boxes on a single, general-purpose platform. To each VM, the TVMM provides the semantics of either an “open box, ” i.e. a general-purpose hardware platform like today’s PCs and workstations, or a “closed box, ” an opaque special-purpose platform that protects the privacy and integrity of its contents like today’s game consoles and cellular phones. The software stack in each VM can be tailored from the hardware interface up to meet the security requirements of its application(s). The hardware and TVMM can act as a trusted party to allow closed-box VMs to cryptographically identify the software they run, i.e. what is in the box, to remote parties. We explore the strengths and limitations of this architecture by describing our prototype implementation and several applications that we developed for it.

No secure network file system has ever grown to span the In-ternet. Existing systems all lack adequate key management for security at a global scale. Given the diversity of the In-ternet, any particular mechanism a file system employs to manage keys will fail to support many types of use. We propose separating key management from file system security, letting the world share a single global file system no matter how individuals manage keys. We present SFS, a se-cure file system that avoids internal key management. While other file systems need key management to map file names to encryption keys, SFS file names effectively contain public keys, making them self-certifying pathnames. Key manage-ment in SFS occurs outside of the file system, in whatever procedure users choose to generate file names. Self-certifying pathnames free SFS clients from any notion of administrative realm, making inter-realm file sharing triv-ial. They let users authenticate servers through a number of different techniques. The file namespace doubles as a key certification namespace, so that people can realize many key management schemes using only standard file utilities. Fi-nally, with self-certifying pathnames, people can bootstrap one key management mechanism using another. These prop-erties make SFS more versatile than any file system with built-in key management.

We address the problem of authorization in large-scale, open...

This paper presents Sharp, a framework for secure distributed resource management in an Internet-scale computing infrastructure. The cornerstone of Sharp is a construct to represent cryptographically protected resource claims— promises or rights to control resources for designated time intervals—together with secure mechanisms to subdivide and delegate claims across a network of resource managers. These mechanisms enable flexible resource peering: sites may trade their resources with peering partners or contribute them to a federation according to local policies. A separation of claims into tickets and leases allows coordinated resource management across the system while preserving site autonomy and local control over resources. Sharp also introduces mechanisms for controlled, accountable oversubscription of resource claims as a fundamental tool for dependable, efficient resource management. We present experimental results from a Sharp prototype for PlanetLab, and illustrate its use with a decentralized barter economy for global PlanetLab resources. The results demonstrate the power and practicality of the architecture, and the effectiveness of oversubscription for protecting resource availability in the presence of failures.

In this paper, we demonstrate the power of providing a common set of Operating System services to wide-area applications, including mechanisms for naming, persistent storage, remote process execution, resource management, authentication, and security. On a single machine, application developers can rely on the local operating system to provide these abstractions. In the wide area, however, application developers are forced to build these abstractions themselves or to do without. This ad-hoc approach often results in individual programmers implementing non-optimal solutions, wasting both programmer effort and system resources. To address these problems, we are building a system, WebOS, that provides basic operating systems services needed to build applications that are geographically distributed, highly available, incrementally scalable, and dynamically reconfigurable. Experience with a number of applications developed under WebOS indicates that it simplifies system development and improves resource utilization. In particular, we use WebOS to implement Rent-A-Server to provide dynamic replication of overloaded Web services across the wide area in response to client demands.

Rivest and Lampson have recently introduced SDSI, a Simple Distributed Security Infrastructure. One of the important innovations of SDSI is the use of linked local name spaces. This paper suggests a logical explanation of SDSI's local name spaces, as a complement to the operational explanation given in the SDSI definition.

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