nonce , N2 problem

nonce , N2 problem

1. What is a nonce?
2. What is the N2 problem?
3. Name a protocol that uses a KDC for user authentication.
4. What is the purpose of the Kerberos authentication server?
5. What is the purpose of the Kerberos ticket-granting server?
6. What is the purpose of X,S09?
7. What is a certification authority?

nonce , N2 problem