Outline for April 27, 2000

1. Authentication protocols?
   1. classical: need trusted third party for both secrecy, authentication
   2. public key: need to verify to whom public key belongs
2. Challenge-response
   1. UNIX passwords
   2. Kerberos
   3. S/Key
   4. Diffie-Hellman and Sun's Secure RPC
3. Public key
   1. Standard: encipher with private key, decipher with public key
   2. Binding public keys to identity: certificates
   3. X.509, PGP web of trust
   4. PEM hierarchy of certification