Mahesh Kallahalla

Plutus is a cryptographic storage system that enables secure file sharing without placing much trust on the file servers. In particular, it makes novel use of cryptographic primitives to protect and share files. Plutus features highly scalable key management while allowing individual users to retain direct control over who gets access to their files. We explain the mechanisms in Plutus to reduce the number of cryptographic keys exchanged between users by using filegroups, distinguish file read and write access, handle user revocation efficiently, and allow an untrusted server to authorize file writes. We have built a prototype of Plutus on OpenAFS. Measurements of this prototype show that Plutus achieves strong security with overhead comparable to systems that encrypt all network traffic. 1

Maintaining the highest levels of availability for content providers is challenging in the face of scale, network evolution and complexity. Little, however, is known about failures large content providers are susceptible to, and what mechanisms they employ to ensure high availability. From a detailed analysis of over 100 high-impact failure events in a global-scale content provider encompassing several data centers and two WANs, we quantify several dimensions of availability failures. We find that failures are evenly distributed across different network types and planes, but that a large number of failures happen when a management operation is in progress within the network. We discuss some of these failures in detail, and also describe our design principles for high availability motivated by these failures, including using defense in depth, maintaining consistency across planes, failing open on large failures, carefully preventing and avoiding failures, and assessing root cause quickly. Our findings suggest that, as networks become more complicated, failures lurk everywhere, and, counter-intuitively, continuous incremental evolution of the network can, when applied together with our design principles, result in a more robust network.

We present the design of Espresso, Google's SDN-based Internet peering edge routing infrastructure. This architecture grew out of a need to exponentially scale the Internet edge cost-effectively and to enable application-aware routing at Internet-peering scale. Espresso utilizes commodity switches and host-based routing/packet processing to implement a novel fine-grained traffic engineering capability. Overall, Espresso provides Google a scalable peering edge that is programmable, reliable, and integrated with global traffic systems. Espresso also greatly accelerated deployment of new networking features at our peering edge. Espresso has been in production for two years and serves over 22% of Google's total traffic to the Internet.

There are a variety of ways to ensure the security of data and the integrity of data transfer, depending on the set of anticipated attacks, the level of security desired by data owners, and the level of inconvenience users are willing to tolerate. Current storage systems secure data either by encrypting data on the wire, or by encrypting data on the disk. These systems seem very different, and currently there are no common parameters for comparing them. In this paper we propose a framework in which both types of systems can be evaluated along the security and performance axes. In particular, we show that all of the existing systems merely make different trade-offs along a single continuum and among a set of related security primitives. We use a trace from a time-sharing UNIX server used by a medium-sized workgroup to quantify the costs associated with each of these secure storage systems. We show that encrypt-on-disk systems offer both increased security and improved performance over encrypt-on-wire in the traced environment. 1

Utility computing aims to aggregate server, network, and storage systems into a single, centrally managed pool of resources. SoftUDC, a virtual machine monitor, lets applications and administrative domains share physical resources while maintaining full functional isolation.