Last time

1
04/29

• Last time
• Diffie-Hellman key exchange protocol
• a message passing problem
• This time
• postmortem on the message-passing problem
• RSA
• midterm review
• Administrative
• review schedule for rest of quarter
• Work
• midterm Thursday 5/1, covers all reading material
  through Chapter 9
• first assignment back Thursday or Tuesday notes
  on book questions available on the course web
  tomorrow
• second assignment out 5/6, due 5/15
• light reading for Dittrich's lecture

2
Postmortem on the Message-Passing Problem

• The problem Alices were given a message and
  told to send it to Bobs within an hour.
• Eves were listening to all messages between
  Alices and Bobs, and had 24 hours to decode
• The result a message (of sorts) was sent, but
  not decoded
• Why the failure?
• What happened, and what could have happened to
  make success more likely?

3
Pre-Midterm Reading

• Bishop Chapter 1 Overview
• Schneier, excerpts from Secrets and Lies
• Bishop, Chapter 2 Access control matrices
• Bishop, Chapter 4 Security Policies (overview)
• Bishop, Chapter 5 Confidentiality Policies
• skip 5.2.3, 5.2.4, 5.4
• Bishop, Chapter 6 Integrity Policies
• Bishop, Chapter 7 Hybrid Policies
• skip 7.1.2
• "Inside the Orange Book" chapter from Computer
  Security
• Bishop, Chapter 9 Basic Cryptography
• Two chapters from Crypto by Steven Levy "The
  Standard" and "Public Key"

4
Bishop Chapter 1 Overview

• Basic components confidentiality, integrity,
  availability
• Threats disclosure, deception, disruption,
  usurpation
• Policy and mechanism
• Goals of security prevention, detection,
  recovery
• Trust and assurance
• Operational issues
• the role of cost-benefit analysis
• Human issues

5
Schneier Secrets and Lies

• Security as a property of a system
• Nature of attacks (why are attacks the same as
  and different from security breach in
  conventional systems)
• Criminal, publicity, and legal attacks
• Knowing your adversaries motives and resources
• Security needs
• security versus integrity versus privacy versus
  anonymity

6
Bishop Chapter 2 Access Control Matrix

• State of a system and protection state
• access control matrix describes a protection
  state
• Subjects, objects, and rights
• Control of access of aggregate properties (access
  controlled by history)
• Changes to the matrix attenuation of privilege

7
Bishop Chapter 4 Policies

• Definition of a security model, a security
  policy, a secure system, and a security
  mechanism
• Definition of confidentiality, integrity, and
  availability
• Military versus commercial policies
• Types of access control discretionary versus
  mandatory versus originator controlled
• Policy languages high-level versus low-level

8
Bishop Chapter 5 Confidentiality Policies

• The goal of a confidentiality policy
• The Bell-LaPadula model
• preliminary version and full version
• The MAC system for mandatory access control
• Tranquility

9
Bishop Chapter 6 Integrity Policies

• Lipner's basic requirements, and justifications
  for them
• Basic principles
• separation of duty
• separation of function
• auditing
• The Biba integrity model
• low water mark, ring, strict model
• Lipner's implementation (Biba / Bell LaPadula
  combo)
• Clark-Wilson model (transactions, constrained
  data items, integrity constraints)

10
Bishop Chapter 7 Hybrid Policies

• Chinese Wall model
• Clinical Information Systems security policy
• Originator Controlled access control
• Role-based access control

11
Inside the Orange Book

• Basic purpose of the book measurement,
  guidance, acquisition
• Four broad divisions of protection
• what are D, C, B, A, and what technology
  distinguishes them
• Trusted computing base
• Policy requirements discretionary access
  control, object reuse, labels, mandatory access
  control
• Accountability requirements authentication,
  trusted path, audit
• Assurance requirements operational assurance,
  life-cycle assurance
• Documentation requirements
• Compartmented Mode Workstations

12
Bishop Chapter 9 Basic Cryptography

• Terms cryptosystem, plaintext, ciphertext
• Types of attacks ciphertext only, known
  plaintext, chosen plaintext, adaptive plaintext
• Transposition ciphers
• Substitution ciphers
• Vignere
• cracking substitution ciphers
• word frequencies, index of coincidence, Kasiski
  method
• one-time pad
• DES and AES
• Feistel ciphers, diffusion and confusion
• Public key Diffie-Hellman and RSA