/pdf/a-break-in-the-clouds-towards-a-cloud-definition-svovsw1r5a.pdf

A Break in the Clouds: Towards a Cloud Definition

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The Precariat. The New Dangerous Class

The course is focused on historical texts, most of them philosophical. Context for understanding the texts and the course of democratic development will be provided in lecture and discussions, and by some background readings (Dunn). We begin with the remarkable Athenian democracy, and its frequent enemy the Spartan oligarchy. In Athens legislation was passed directly by an assembly of all citizens, and executive officials were selected by lot rather than by competitive election. Athenian oligarchs such as Plato more admired Sparta, and their disdain for the democracy became the judgment of the ages, until well after the modern democratic revolutions. Marsilius of Padua in the early Middle Ages argued for popular sovereignty. The Italian citystates of the Middle Ages did without kings, and looked back to Rome and Greece for republican models. During the English Civil War republicans debated whether the few or the many should be full citizens of the regime. The English, French, and American revolutions struggled with justifying and establishing a representative democracy suitable for a large state, and relied on election rather than lot to select officials. The English established a constitutional monarchy, admired in Europe, and adapted by the Americans in their republican constitution. The American Revolution helped inspire the French, and the French inspired republican and democratic revolution throughout Europe during the 19 century.

/pdf/democracy-and-its-critics-2zxg086s7q.pdf

Democracy and Its Critics

The increasing popularity of cloud storage services has lead companies that handle critical data to think about using these services for their storage needs. Medical record databases, large biomedical datasets, historical information about power systems and financial data are some examples of critical data that could be moved to the cloud. However, the reliability and security of data stored in the cloud still remain major concerns. In this work we present DepSky, a system that improves the availability, integrity, and confidentiality of information stored in the cloud through the encryption, encoding, and replication of the data on diverse clouds that form a cloud-of-clouds. We deployed our system using four commercial clouds and used PlanetLab to run clients accessing the service from different countries. We observed that our protocols improved the perceived availability, and in most cases, the access latency, when compared with cloud providers individually. Moreover, the monetary costs of using DepSky in this scenario is at most twice the cost of using a single cloud, which is optimal and seems to be a reasonable cost, given the benefits.

DepSky: Dependable and Secure Storage in a Cloud-of-Clouds

The increasing popularity of cloud storage services has lead companies that handle critical data to think about using these services for their storage needs. Medical record databases, power system historical information and financial data are some examples of critical data that could be moved to the cloud. However, the reliability and security of data stored in the cloud still remain major concerns. In this paper we present DEPSKY, a system that improves the availability, integrity and confidentiality of information stored in the cloud through the encryption, encoding and replication of the data on diverse clouds that form a cloud-of-clouds. We deployed our system using four commercial clouds and used PlanetLab to run clients accessing the service from different countries. We observed that our protocols improved the perceived availability and, in most cases, the access latency when compared with cloud providers individually. Moreover, the monetary costs of using DEPSKY on this scenario is twice the cost of using a single cloud, which is optimal and seems to be a reasonable cost, given the benefits.

/pdf/depsky-dependable-and-secure-storage-in-a-cloud-of-clouds-3j2o5dtw2h.pdf

DepSky: dependable and secure storage in a cloud-of-clouds

In-network source authentication and path validation are fundamental primitives to construct higher-level security mechanisms such as DDoS mitigation, path compliance, packet attribution, or protection against flow redirection. Unfortunately, currently proposed solutions either fall short of addressing important security concerns or require a substantial amount of router overhead. In this paper, we propose lightweight, scalable, and secure protocols for shared key setup, source authentication, and path validation. Our prototype implementation demonstrates the efficiency and scalability of the protocols, especially for software-based implementations.

/pdf/lightweight-source-authentication-and-path-validation-1saq84jubm.pdf

Lightweight source authentication and path validation

Providing an adequate security level in Cloud Environments is currently an extremely active research area. More specifically, malicious behaviors targeting large-scale Cloud data repositories (e.g. Denial of Service attacks) may drastically degrade the overall performance of such systems and cannot be detected by typical authentication mechanisms. In this paper we propose a generic security management framework allowing providers of Cloud data management systems to define and enforce complex security policies. This security framework is designed to detect and stop a large array of attacks defined through an expressive policy description language and to be easily interfaced with various data management systems. We show that we can efficiently protect a data storage system by evaluating our security framework on top of the BlobSeer data management platform. We evaluate the benefits of preventing a DoS attack targeted towards BlobSeer through experiments performed on the Grid'5000 testbed.

https://hal.inria.fr/inria-00536603/document

Managing Data Access on Clouds: A Generic Framework for Enforcing Security Policies

A key-value store (KVS) offers functions for storing and retrieving values associated with unique keys. KVSs have become widely used as shared storage solutions for Internet-scale distributed applications.We present a fault-tolerant wait-free efficient algorithm that emulates a multi-reader multi-writer register from a set of KVS replicas in an asynchronous environment. Our implementation serves an unbounded number of clients that use the storage. It tolerates crashes of a minority of the KVSs and crashes of any number of clients. We provide two variants of our algorithm: one implementing an atomic register and one implementing a regular register; the latter does not require read operations to store data at the underlying KVSs. We note that applying state-of-the-art reliable storage solutions to this scenario is either impossible or prohibitively inefficient.

/pdf/robust-data-sharing-with-key-value-stores-hbspg3fynf.pdf

Robust data sharing with key-value stores

A key-value store (KVS) offers functions for storing and retrieving values associated with unique keys. KVSs have become the most popular way to access Internet-scale “cloud” storage systems. We present an efficient wait-free algorithm that emulates multi-reader multi-writer storage from a set of potentially faulty KVS replicas in an asynchronous environment. Our implementation serves an unbounded number of clients that use the storage concurrently. It tolerates crashes of a minority of the KVSs and crashes of any number of clients. Our algorithm minimizes the space overhead at the KVSs and comes in two variants providing regular and atomic semantics, respectively. Compared with prior solutions, it is inherently scalable and allows clients to write concurrently. Because of the limited interface of a KVS, textbook-style solutions for reliable storage either do not work or incur a prohibitively large storage overhead. Our algorithm maintains two copies of the stored value per KVS in the common case, and we show that this is indeed necessary. If there are concurrent write operations, the maximum space complexity of the algorithm grows in proportion to the point contention. A series of simulations explore the behavior of the algorithm, and benchmarks obtained with KVS cloud-storage providers demonstrate its practicality.

This paper proposes a Scalable Internet Bandwidth Reservation Architecture (SIBRA) as a new approach against DDoS attacks, which, until now, continue to be a menace on today's Internet. SIBRA provides scalable inter-domain resource allocations and botnet-size independence, an important property to realize why previous defense approaches are insufficient. Botnet-size independence enables two end hosts to set up communication regardless of the size of distributed botnets in any Autonomous System in the Internet. SIBRA thus ends the arms race between DDoS attackers and defenders. Furthermore, SIBRA is based on purely stateless operations for reservation renewal, flow monitoring, and policing, resulting in highly efficient router operation, which is demonstrated with a full implementation. Finally, SIBRA supports Dynamic Interdomain Leased Lines (DILLs), offering new business opportunities for ISPs.

/pdf/sibra-scalable-internet-bandwidth-reservation-architecture-v8itphewih.pdf

Cristina Basescu

Papers

Lightweight source authentication and path validation

Managing Data Access on Clouds: A Generic Framework for Enforcing Security Policies

Robust data sharing with key-value stores

Robust data sharing with key-value stores

SIBRA: Scalable Internet Bandwidth Reservation Architecture