CSR---PDOS: Distributed Capability Systems

该项目正在为广域协作系统，特别是文件系统开发一种新的基于能力的安全基础设施。 新的基于能力的方法（chits）提供了实施几个强大的安全不变量的能力，而不损害本地化控制和效率的能力的传统优势。 由此产生的功能解决了一些问题，以前阻止能力被广泛应用于分布式system.This系统的概念，这是一种新的形式的能力，允许细粒度的操作的数据集，是chit的目标，并设置的权利，chit实现。 Chits还支持定义和验证灵活的身份，允许他们实施从允许匿名访问到提供严格责任的安全策略。Chits允许远程委托，允许用户在不联系服务器的情况下派生新的Chits，这些新的Chits将授予其他用户对数据（子集）的（有限）访问权限。 远程委托从其应用中体现了访问控制策略的规范。 Chit允许细粒度的撤销，允许Chit保持器拒绝对数据（子集）的访问。Chit提供了一种创建协作应用程序的有效方法，在该应用程序中，由用户（而不是服务器和管理员）定义策略并授予其他用户访问权限。 一个正式的分类的单据操作和权利正在开发中，单据被嵌入一个通用的单据库，该库被用来建立一个协作文件系统。

This project is developing a novel capability-based security infrastructure for wide-area collaborative systems, especially file systems. The new capability-based approach (chits) provides the ability to enforce several strong security invariants, without compromising the traditional advantages of capabilities in localized control and efficiency. The resulting functionality addresses a number of issues that have previously prevented capabilities from being widely used in distributed systems.This system is based around the concept of a chit, which is a new form of capability that permits fine-grained manipulation of both the set of data that is the chit's target, and of the set of rights that the chit materializes. Chits also support defining and verifying flexible identities, allowing them to implement security policies that range from allowing anonymous access to providing strict accountability.Chits permit remote delegation, allowing users to, without contacting a server, derive new chits that will grant other users (limited) access to (a subset of) the data. Remote delegation decouples the specification of access control policy from its application. Chits permit fine grained revocation, allowing a chit holder to deny accesses to (a subset of) data.Chits provide an effective means of creating collaborative applications in which users, not servers and administrators, define policy and grant access to other users. A formal taxonomy of chit operations and rights is being developed, the chits are being embedded a general chit library, and the library is being used to build a collaborative file system.