Lecture #32
- Announce
- Quiz Today
- Continue Reading Chapter 11, Security
Computer Security
- Important Topic
- Good Passwords and Cracking
- Brief Case Combination Locks
- Briefcase combination lock
- Analysis
- number of wheels
- number of positions
- time per trial
- alternatives
- Password on a Computer
- More possibilities per "wheel" or position
- Faster Cracking
- Dictionary Attacks
- Picking a good UNIX password
- Encryption
- Polyalphabetic Substitution
- The Vignere Cypher
- The Babbit Solution
- Cypher Reuse
- The Magic Encoder Ring?
- One Time Pads
- Can be Absolutely Secure
- Computers and Random Number Generators
- The Key Exchange Problem
- Threats
- Using your "secure" channel
- A Padlock Analogy
- Whitfield Diffie, Martin Hellman, and Ralph Merkle solution
- Public Key Encryption
- Traditional Cyphers
- A Padlock Analogy
- Diffie Proposal in 1975
- Non-Commutativity of Standard Methods
- Failure of Commutative Methods
- Rivest, Shamir, and Adleman (RSA) Encryption