Authentication Problem:How do you prove to someone that you are whom you claim to be? Any system with access control must solve this problem. ■ Goals: -1.Mutual Authentication:each party authenticates itself to the other party. -2.Key Establishment:establish a session key.This session key will be used to encrypt and decrypt messages between the two parties using symmetric key cryptography. Methods -Authentication with asymmetric keys -Authentication with symmetric keys -Human authentication 22 Authentication  Problem: How do you prove to someone that you are whom you claim to be?  Any system with access control must solve this problem.  Goals: ─ 1. Mutual Authentication: each party authenticates itself to the other party. ─ 2. Key Establishment: establish a session key. This session key will be used to encrypt and decrypt messages between the two parties using symmetric key cryptography.  Methods ─ Authentication with asymmetric keys ─ Authentication with symmetric keys ─ Human authentication