1. Security in Distributed Systems – A look at Globus
Stephen Rook
October 25, 2007

2. Overview Background – security’s role in distributed systems
Overview of Globus
Security Policy of Globus

3. Security Overview
Why do we need to consider security issues for distributed systems?
The main goal is to protect the system and its resources from unauthorized use.
Authentication
Ex: Is “Adam” truly Adam, an employee in good-standing of a company’s branch in New York, or is “Adam” truly Damien, a recently fired employee whose ultimate goal is to take down the company server?
Authorization
Ex: Does Adam have write privileges on a file foo.txt located on the company’s Los Angeles server?

4. Security Overview (2)
Why is it so difficult to implement security on distributed systems?
Resources can span many geographic domains.
The system must keep track of where its resources are located
Ex: An employee on subnetwork A in the U.S. wishes to access a file stored on the company server on subnetwork C located in Germany.
For some resources, only certain classes of users can be allowed access.
Falls under the authorization domain
Ex: Suppose we have two low-level employees, John and Sam. John should not be able to access Sam’s employment record even though they both work for the same company. However, Sam’s supervisor should have access rights.

5. Security Overview (3) Most distributed systems are heterogeneous
They are comprised of mixed types of computers and resources
Ex: Grid systems
Need to define protocols to safely access system components no matter where such components reside

6. Globus Proposed by Foster, Kesselman, and Tuecke in 1998
Version 0.1 (the first) was implemented in April 2000
Version 4.1 was released September 2007
Designed for grid computing
Security of the vast number of components in the entire system is the prime concern

7. Globus Security Policy
Assumption: The system consists of multiple administrative domains or subsystems.
Multiple existing disjoint subsystems (most likely heterogeneous) need to be seamlessly integrated under a minimal number of standardized security protocols.
Local operations are subject to local domain security policy only.

8. References
Tanenbaum and Van Steen. Distributed Systems – Principles and Paradigms. 2nd ed
Foster and Kesselman. “Globus: A Metacomputing Infrastructure Toolkit.”
Foster et al. “A Security Architecture for Computational Grids.”
Globus Alliance.