Abstract
Koglin, Yunhua Ph.D., Purdue University, December, 2006. Security Mechanisms for
Content Distribution Networks. Major Professor: Elisa Bertino.
Securing data is becoming a crucial need for most internet-based applications. In
this research, we investigate security mechanisms for content distribution networks.
We address the problem of how to ensure that data, when moving among di erent
parties, are modi ed only according to the stated policies. We cast our solution in supporting
parallel and distributed secure updates to XML documents. The approach,
based on the use of a security region-object parallel
ow (S-RPF) graph protocol, allows
di erent users to simultaneously update di erent portions of the same document,
according to the speci ed access control policies. It ensures data con dentiality and
integrity. Additionally, it supports a decentralized management of update operations
in that a subject can exercise its privileges and verify the correctness of the operations
performed so far on the document without interacting, in most of the cases, with the
document server.
We then extend our document update application into Byzantine and failure prone
systems by removing the trusted party which is responsible for recovery of the document.
We have developed an approach which uses a group of delegates for recovering
documents. Many optimizations have been provided.
We improve previous solutions by proposing a scalable distributed protocol which
uses cryptographic techniques to provide dynamic group communications, participating
anonymity and completeness, and privacy on access privileges.
Other security problems such as con dentiality and availability are also investigated
in the application of content-based publish/subscribe (pub/sub) systems. We
propose a hierarchical event forwarding scheme which increases system availability by
x
tolerating some broker failures. Our approach can e ciently determine the subscription
groups to which an event must be delivered by exploiting locality. Moreover, we
propose an e cient encryption scheme, under which a broker encrypts an event only
once. The encryption key can be e ciently derive
Contents
LIST OF TABLES
LIST OF FIGURES
ABSTRACT
1 Introduction
1.1 Objectives of this work
2 An update protocol for XML documents in distributed and cooperative systems
2.1 Preliminaries
2.1.1 Flow and access control policies
2.1.2 Atomic elements and document regions
2.3 S-RPF protocols
2.3.1 Assumptions
2.3.2 Server protocol
2.3.3 S-RPF construction
2.3.4 Control information
2.3.5 Subject protocol
2.3.6 Recovery protocol
2.4 Analysis and discussions
2.4.1 Correctness analysis
2.4.2 Complexity analysis
2.5 Conclusion and future work
3 XML document updates in Byzantine and failure-prone distributed systems
3.1 Motivating example
3.2 Related work
3.3 Speci cation languages
3.4 Control information
3.4.1 Preliminary de nitions
3.4.2 Document control information
3.5 General system overview
3.5.1 Assumptions
3.5.2 Protocol parameters setting
3.6 Distributed and cooperative update process protocols
3.6.1 Terminology and structures
3.6.2 DO protocol
3.6.3 Subject protocol
3.6.4 Delegate protocol
3.7 Recovery
3.8 Performance evaluation
3.8.1 Experimental setup
3.8.2 Results
3.9 Conclusion and future work
4 A cryptographic approach to access control for privacy preserving collaborations
4.1 Introduction
4.2 Model
4.2.1 Threats
4.3 Preliminary
4.4 Secure collaborative document processing
4.4.1 Updating process protocol
4.4.2 Recovery protocol
4.5 Security analysis
4.5.1 Con dentiality
4.5.2 Integrity
4.5.3 Privacy
4.5.4 Participant completeness
5 Timely dissemination of con dential events in content-based publish/subscribe
systems
5.1 Introduction
5.2 Model
5.3 Hierarchial event routing scheme
5.3.1 Hierarchy event routing
5.3.2 Discussion
5.4 Con dentiality-preserving event delivery
5.4.1 Discussion
5.4.2 Dynamics and rekeying
5.5 Simulation results
5.5.1 Space Requirements
5.5.2 Time Delay
5.5.3 Broker Involvement
5.6 Related work
5.7 Conclusions and future work
LIST OF REFERENCES
VITA
