Outline for November 17, 2006

Reading: §9.4, 10.1–10.2

1. Greetings and felicitations!
   1. Puzzle of the day
2. Cryptographic Checksums
   1. Function y = h(x): easy to compute y given x; computationally infeasible to compute x given y
   2. Variant: given x and y, computationally infeasible to find a second x′ such that y = h(x′)
   3. Keyed vs. keyless
3. Key Exchange
   1. Needham-Schroeder and Kerberos