Computer Security Issues
Exploited Types of Vulnerabilities:
Computer Emergency Response Team (CERT)
(the official site to get up-to-date information on the status of vulnerabilities)
Security Focus
(reports on unvealed vulnerabilities)
Defending Against Breaches:
Protecting a Private Network: The Altavista Firewall
(very readable and comprehensive paper)
Denial of Service Attacks
(a survey paper with many related links)
Applied Cryptographic Protocols:
Introduction to Public-key Cryptography
(very high-level overview)
Secure Sockets Layer (SSL)
(high-level overview with examples)
NIST Cryptographic Toolkit
Applications:
Digital Money
Miscellaneous:
Ron Rivest's Cryptography and Security Links
Collection of Security-related Links