Security Evaluation

Security Evaluation

Bruce Schneier
Beyond Fear
Copernicus books
2003
ISBN: 0387026207

Agenda

• What is security?
• Five steps process to analyse and evaluate security systems, technologies and practices
• 3 final rules

What is security?

• Security is about preventing adverse consequences from the intentional and unwarranted actions of others
  • prevention
  • intentional actions
  • unwarranted from the point of view of the defender
  • attackers and defenders
  • attacks against assets
  • countermeasures

Five steps process

• Five steps process to analyse and evaluate security systems, technologies and practices
  1. What assets are you trying to protect?
  2. What are the risks to these assets?
  3. How well does the security solution mitigate those risks?
  4. What other risks does the security solution cause?
  5. What costs and trade-offs does the security solution impose?
• is 3 > 4 + 5 ?

3 final rules

1. risk demystification
   • understand the threats
   • understand the risks
   • understand the effectiveness of the countermeasures
   • understand the trade-offs
   • understand the unintended consequences

3 final rules

2. secrecy demystification
   • it is brittle
   • it causes additional security problems because it conceals abuse
   • it prevents from having the information needed to make sensible security trade-offs
3. agenda demystification

Questions?