I gave a series of lectures on security at TCS Excellence in Computer Science Week 2005, at the Tata Research Development and Design Center in Pune, India.
Links: Abstract, Acrobat, Word
Email: firstname.lastname@example.org. This paper is at http://research.microsoft.com.
These lectures cover the basic principles of trust and security for distributed systems under the following headings:
Introduction: what is security?
Principals, the “speaks for” relation, and chains of responsibility
Secure channels and encryption
Names and groups