What are four requirements for kerberos?

The four requirements for Kerberos are:

1. Clock Synchronization: All participating systems must have their clocks synchronized to prevent replay attacks.
2. Secure Communication Channels: The network must be secure to prevent eavesdropping and tampering with messages.
3. Authentication Server: A trusted authentication server is needed to verify users' identities and issue tickets.
4. Mutual Authentication: Both the client and server must be able to verify each other's identities to establish a secure connection.