Outline for February 22/25, 2002

Reading: §9.4, §10.2, §10.4.2-10.4.3, §10.5.1-10.5.1.1, §10.5.2, §10.6 except §10.6.2.2

1. Greetings and Felicitations
2. Puzzle of the day
3. 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
4. MD5, HMAC
4. Key Exchange
1. Needham-Schroeder and Kerberos
2. Public key; man-in-the-middle attacks
5. Cryptographic Key Infrastructure
1. Certificates (X.509, PGP)
2. Certificate, key revocation
3. Key Escrow
6. Digital Signatures