| |
|
This course is an introduction to the basic
theory and practice of cryptographic techniques used in computer
security. The course is intended for advanced undergraduates and
graduate students.
Topics - tentative
Introduction
- History. Overview of cryptography. Attack models.
Secret Key Encryption
- Information theoretic security. One time pad.
Unbreakability of one time pad. How to break a one time
pad. Stream ciphers.
- Feistel networks. DES. Modes of operation (+ DESX).
Luby-Rackoff.
- Vulnerabilities: Time-space tradeoffs, Differential &
Linear cryptanalysis, Meet-in-the-middle.
- Key distribution using Trusted Third Parties.
- Merkle puzzels.
Public Key Encryption
- Arithmetic modulo primes. Algorithms: bignum arithmetic,
repeated squaring.
- Discrete log. Diffie-Hellman Key Exchange. ElGamal.
Random self reduction.
- Arithmetic modulo composites.
- RSA (CRT). Rabin. Bit security.
- Vulnerabilities: Factoring, Small private key, broadcast,
Random padding. Timing attacks.
Hashing
- Motivation, applications (e.g. virus protection). Message
Authentication Codes (MAC).
- Cryptographically Secure Hashing.
Digital Signatures
- How to sign using RSA (Bellare-Rogaway). The Digital
Signature Standard (DSS).
- Signature schemes. Lamport and Merkle schemes.
Certificates.
Real world crypto
- Trust management. Certificate chains, cross
certification.
- PGP, SSL, ISAKMP/Oakley.
- Secure file systems. CFS.
- Key Recovery/escrow.
Authentication
- UNIX/NT Passwords, salts. One time passwords, S/Key.
Encrypted Key Exchange (EKE). Challenge response
authentication.
- Definition of zero knowledge proof of knowledge,
examples. The Fiat-Shamir protocol.
- Kerberos V4. The Needham-Schroeder protocol.
Digital Cash
- Anonymous cash. Online vs. Offline schemes.
- Micropayments: Millicent, payword, micromint. Real
Systems: Mondex, VisaCash.
Final Lecture
|