Kerberos is a network authentication protocol that provides secure communication over an insecure network. The Kerberos protocol involves several steps to authenticate users and secure their communication. However, it's worth noting that Kerberos version 4 is an older version and has been largely replaced by Kerberos version 5, which is more commonly used today. Nevertheless, I can provide you with an overview of the six steps involved in the Kerberos version 4 protocol:
Step 1: User Login and Service Request
- The user logs in to the system and requests specific services from the host.
- The user initiates a request for a ticket-granting service.
Step 2: Authentication Server Verification and Ticket Granting
- The Authentication Server verifies the user's access rights by checking against a database.
- If the user is authenticated, the Authentication Server generates a ticket-granting ticket (TGT) and a session key.
- The TGT and session key are encrypted using the user's password as the encryption key.
Step 3: Ticket Transmission to Ticket Granting Server
- The encrypted TGT is sent by the user to the Ticket Granting Server (TGS).
- The TGT contains authenticators such as the user's name and network address.
Step 4: Ticket Granting Server Validation and Ticket Generation
- The Ticket Granting Server decrypts the received TGT using the user's password.
- The TGS verifies the authenticity of the TGT and the accompanying authenticators.
- If the verification is successful, the TGS generates a ticket for the requested services from the server.
Step 5: Ticket and Authenticator Submission to the Server
- The user submits the ticket received from the TGS, along with an authenticator, to the desired server.
- The ticket contains the necessary information for the server to grant access.
Step 6: Server Verification and Service Access
- The server verifies the submitted ticket and authenticator.
- If the ticket and authenticator are valid, the server grants the user access to the requested service.
- The user can now access the services provided by the server.
These steps outline a basic overview of the Kerberos version 4 protocol. However, please keep in mind that Kerberos version 5 is the recommended version for most implementations today, as it offers improved security and additional features compared to version 4.
