Principles Of Information Security

Summary

• Firsts from Computing Pioneers
• Terminologies
• Levels of Protection
• Design Principles

Firsts from Computing Pioneers

• First vision for a network of computers
  • JCR Licklider, 1963
• First computer to computer communication
  • “The day the infant internet uttered its first words”, 1969
• First e-mail
  • Ray Tomlinson, 1971

Terminologies

When to release info?

• Privacy
  • Individual right to relase information that they own
• Security
  • How do systems respect user’s privacy
    • Protection
    • Authentication

Comprehensive set of security concerns

• Unauthorized information release
• Unauthorized information modification
• Unauthorized denial of use
  • First mention of DOS attacks

Goal of Secure System

• “Prevent all violations”
  • Negative statement
  • Like saying “My code has no bugs”
  • At best, false sense of security

Levels of Protection

• Unprotected
  • MSDOS
• All or Nothing
  • IBM’s VM-370
  • Most time-sharing systems
• Controlled Sharing
  • ACLs for files
• User Programmed Sharing Controls
  • Unix-like semantics for files
• Strings on Info
  • “Top Secret”
  • Need to deal with dynamics of use

Design Principles

• Economy of Mechanisms
  • easy to verify
• Fail-safe Defaults
  • Explicitly allow access
    • Default should not be no access
• Complete Mediation
  • Don’t take shortcuts
  • Caching password is a bad idea
• Open Design
  • publish design
  • protect keys
• Separation of Privilege
  • two keys to open vault
• Least Privilege
  • “need to know” based controls
• Least Common Mechanism
  • library vs in-kernel
• Psychological Acceptability
  • good UX