We propose embedding executable code fragments in cryptographically protected capabilities to enable flexible discretionary access control in cloud-like computing infrastructures. We are developing this as part of a sports analytics application that runs on a federation of public and enterprise clouds. The capability mechanism is implemented completely in user space. Using a novel combination of X.509 certificates and Javscript code, the capabilities support restricted delegation, confinement, revocation, and rights amplification for secure abstraction.
The capability mechanism proposed by @cite_9 uses keyed cryptographic hashes in a way similar to Amoeba and supports delegation by chaining hashes. Each entry on the chain can contain regular expressions to express which rights are being delegated. The mechanism is less expensive than our approach, but does not support rights amplification and cannot be used for secure abstraction. The MyProxy service @cite_12 uses X.509 proxy certificates to delegate credentials, but lacks facilities for including and evaluating complex rights functions.
@cite_9 @cite_12
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SUMMARY The MyProxy online credential repository has been used by the grid computing community for over four years for managing security credentials in the grid public key infrastructure. MyProxy improves usability by giving users access to their credentials over the network using password authentication, allowing users to delegate their credentials via web browser interfaces to the grid, and supporting credential renewal for long-running jobs. MyProxy helps administrators secure users’ private keys by providing an online service from which users retrieve short-lived credentials without distributing long-lived keys to potentially vulnerable end-systems. This paper describes the MyProxy system and its use. Trust management credentials directly authorize actions, rather than divide the authorization task into authentication and access control. Unlike traditional credentials, which bind keys to principals, trust management credentials bind keys to the authorization to perform certain tasks. The Distributed Credential FileSystem (DisCFS) uses trust management credentials to identify: (1) files being stored; (2) users; and (3) conditions under which their file access is allowed. Users share files by delegating access rights, issuing credentials in the style of traditional capabilities. Credentials permit, for example, access by remote users not known in advance to the file server, which simply enforces sharing policies rather than entangling itself in their management. Throughput and latency benchmarks of our prototype DisCFS implementation indicate performance roughly comparable to NFS version 2, while preserving the advantages of credentials for distributed control. Cloud computing, as an emerging computing paradigm, enables users to remotely store their data into a cloud so as to enjoy scalable services on-demand. Especially for small and medium-sized enterprises with limited budgets, they can achieve cost savings and productivity enhancements by using cloud-based services to manage projects, to make collaborations, and the like. However, allowing cloud service providers (CSPs), which are not in the same trusted domains as enterprise users, to take care of confidential data, may raise potential security and privacy issues. To keep the sensitive user data confidential against untrusted CSPs, a natural way is to apply cryptographic approaches, by disclosing decryption keys only to authorized users. However, when enterprise users outsource confidential data for sharing on cloud servers, the adopted encryption system should not only support fine-grained access control, but also provide high performance, full delegation, and scalability, so as to best serve the needs of accessing data anytime and anywhere, delegating within enterprises, and achieving a dynamic set of users. In this paper, we propose a scheme to help enterprises to efficiently share confidential data on cloud servers. We achieve this goal by first combining the hierarchical identity-based encryption (HIBE) system and the ciphertext-policy attribute-based encryption (CP-ABE) system, and then making a performance-expressivity tradeoff, finally applying proxy re-encryption and lazy re-encryption to our scheme. This paper presents the Merlin network management framework. With Merlin, administrators express network policy using programs in a declarative language based on logical predicates and regular expressions. The Merlin compiler automatically partitions these programs into components that can be placed on a variety of devices including switches, middleboxes, and end hosts. It uses a constraint solver and parameterizable heuristics to allocate resources such as paths and bandwidth. To ease the administration of federated networks, Merlin provides mechanisms for delegating management of sub-policies to tenants, along with tools for verifying that delegated sub-policies do not violate global constraints. Overall, Merlin simplifies the task of network administration by providing high-level abstractions for directly specifying network policy.