TCS Papers: Sample Questions 473 - 473 of 502

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Question number: 473

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Describe in Detail

What is Kerberos?


  • Authentication service developed at the Massachusetts Institute of Technology using encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.

    • Uses secret-key cryptography to authenticate client-server applications.

    • Encrypted ticket is requested from an authenticated server sequence to use services.

  • It is a ticket based system:

    • Authentication server uses Kerberos ticket to grant server access and then creates a session key based on the requester’s password and another randomized value.

    • The ticket-granting ticket (TGT) is sent to the ticket-granting server (TGS) using the same authentication server.

  • Requester receives encrypted TGS key with a time stamp and the ticket. Key is returned to the requester and decrypted.

    • Requester sends the TGS this information and forwards the encrypted key to the server to obtain the desired service.

    • Server accepts the ticket and performs the desired user service.

  • Gets name from the three-headed dog (Kerberos, or Cerberus) guarding the gates of Hades (Greek mythology).

  • Developed as part of Project Athena - a joint project between the Massachusetts Institute of Technology (MIT), Digital Equipment Corporation, and IBM that ran between 1983 and 1991.

Image of The Kerberos

Image of the Kerberos

Given the image is define the Kerberos