Yu / Jajodia Secure Data Management in Decentralized Systems

1. Auflage 2007
ISBN: 978-0-387-27696-0
Verlag: Springer US
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 462 Seiten, Web PDF

Reihe: Advances in Information Security

The field of database security has expanded greatly, due to the rapid development of the global inter-networked infrastructure. Databases are no longer stand-alone systems accessible only to internal users of organizations. Today, many businesses must allow selective access from different security domains. New data services emerge every day, which brings new and more complex challenges to those whose job is to protect data security. The internet and the web offer means for collecting and sharing data with unprecedented flexibility and convenience, and presents threats and challenges of its own. This book identifies and addresses these new challenges and more. This volume presents a wide range of active areas, closely related to database security by distinguished leaders within this field. Solutions are included. Secure Data Management in Decentralized Systems is designed for a professional audience of practitioners and researchers in industry. This book is suitable for graduate-level students in computer science as well.

Zielgruppe

Professional/practitioner

Autoren/Hrsg.

Yu, Ting

Jajodia, Sushil

Inhaltsverzeichnis

Foundation.- Basic Security Concepts.- Access Control Policies and Languages in Open Environments.- Trusted Recovery.- Access Control for Semi-Structured Data.- Access Control Policy Models for XML.- Optimizing Tree Pattern Queries over Secure XML Databases.- Distributed Trust Management.- Rule-based Policy Specification.- Automated Trust Negotiation in Open Systems.- Building Trust and Security in Peer-to-Peer Systems.- Privacy in Cross-Domain Information Sharing.- Microdata Protection.- ?-Anonymity.- Preserving Privacy in On-line Analytical Processing Data Cubes.- Security in Emerging Data Services.- Search on Encrypted Data.- Rights Assessment for Relational Data.

Leseproben

2 Security Policy (p. 4)

The security policy elaborates on each of the three generic objectives of security- secrecy, integrity, and availability-in the context of a particular system. Thus, com- puter security policies are used like requirements, they are the starting point in the development of any system that has security features. The security policy of a system is the basis for the choice of its protection mechanisms and the techniques used to assure its enforcement of the security policy.

Existing security policies tend to focus only on the secrecy requirement of se- curity. Thus, these policies deal with defining what is authorized or, more simply, arriving at a satisfactory definition of the secrecy component. The choice of a security policy with reasonable consequences is nontrivial and a separate topic in its own right. In fact, security policies are investigated through formal mathematical models. These models have shown, among other things, that the consequences of arbitrary but relatively simple security policies are undecidable and that avoiding this undecidability is nontrivial [5,7,8]. To read more about the formal security models, see [3].

All security policies are stated in terms of objects and subjects. This is because in reasoning about security policies, we must be careful about the distinction between users and the processes that act on behalf of the users. Users are human beings that are recognized by the system as users with an unique identity. This is achieved via identification and authentication mechanisms, the familiar example is a user identi- fier and password.

All system resources are abstractly lumped together as objects and, thus, all ac- tivities within a system can be viewed as sequences of operations on objects. In the relational database context, an object may be a relation, a tuple within a relation, or an attribute value within a tuple. More generally, anything that holds data may be an object, such as memory, directories, interprocess messages, network packets, I10 devices, or physical media.

A subject is an abstraction of the active entities that perform computation in the system. Thus, only subjects can access or manipulate objects. In most cases, within the system a subject is usually a process, job, or task, operating on behalf of some user, although at a higher level of abstraction users may be viewed as subjects. A user can have several subjects running in the system on his or her behalf at the same time, but each subject is associated with only a single user. This requirement is important to ensure the accountability of actions in a system.

Although the subject-object paradigm makes a clear distinction between subjects and objects (subjects are active entities, while objects are passive entities), an entity could be both a subject and an object. The only requirement is that if an entity be- haves like a subject (respectively, object), it must abide by rules of the model that apply to subjects (respectively, objects).

Basic Security Concepts 5

The reason a distinction must be made between users and subjects is that while users are trusted not to deliberately leak information (they do not require a computer system to do so), subjects initiated by the users cannot be trusted to always abide by the security policy.