2007-04-11

1. * Turn in homework; pass out to be graded.

2. What's coming up:
(a) This week --- public key cryptography
(b) Next week -- midterm review and *the* midterm; it will cover
    up through this week's public key crypto.
(c) After that -- quadratic reciprocity; continued fractions; 
       elliptic curve curve crypto.

Today -- the Diffie-Hellman key exchange -- 

3. Story about Michael and Nikita

4. Additive version of Diffie-Hellman -- easy to break

5. Multiplicative version -- much harder.

6. Discrete log problem.
  
7. Man in the middle attack

---- HANDOUT: Log of a session of relevant computation with plots -----