Kerberos Authentication


As the digital world is growing and becoming an integral part of our lives, cybercrime has never been more relevant. No one online is entirely safe, be it any average individual or corporate firm. Experts measure that the damages caused by cybercrimes will cost a hefty $6.1 trillion by the end of this year. The rate of cybercrimes is increasing at a phenomenal speed. One of the main reasons is the continuous revolutions and innovations in artificial intelligence and the internet. This is a sweet and sour situation where it enhances human online capabilities and boosts communication between individuals. However, it has also been proved to be the master weapon of hackers and the last resort if they cannot crack cybersecurity. The world craves stronger cybersecurity to protect its data today. We will discuss one of the most popular authentication protocols- Kerberos.


Kerberos is a computer network authentication protocol that verifies and authenticates two(or more) trusted hosts on an untrusted and unprotected network. Kerberos implements two-way verification and single key cryptography, enabling the system to verify known identities or users working on an unsafe network.

Steps of Kerberos Authentication Protocol

There are three keys involved in the Kerberos authentication process: Client/user key, secret server key, and Ticket Granting Server(TGS) key.

Step 1: The user their client ID to request a ticket from the authentication server.

Step 2: The key distributions verify the user credentials and generate a session key (SK1) through the authentication server, which stays encrypted with the user key.

Step 3: The client then decrypts the SKI and TGT key using the client key to extract information.

Step 4: Then, the client requests another ticket from the KDC using the extracted SK1 and client authenticator.

Step 5: The KDC generates a key that includes a timestamp, client ID, client network address, and SK2. This remains encrypted in the server key.

Step 6: The target server then decrypts the service key SK2, which extracts the authenticator. This information is then used to match the client ID/network address and the service ticket. If it passes, the target server informs the client that it has been verified alongside the server and can now operate on an unsafe network.


  • Fast authentications: As Kerbose uses a unique ticketing system that establishes authentication between the client and server.
  • Tickets are safe: Tickets provided in the Kerberos authentication process are short-lived and one-time passcodes. Thus, hackers cannot intercept and steal as these tickets are one-time use and encrypted most of the time until the target server decrypts them.

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