3i Infotech Placement: Sample Questions 1103 - 1104 of 1245

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Question 1103

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Describe in Detail

Essay▾

What are abstract classes?

Explanation

  • Abstract classes are those for which instances can՚t be created.
  • Class declared abstract may or may not include abstract methods.
  • An abstract method is declared without an implementation
  • In object-oriented programming (OOP) , classes represent objects in the domain of the problem.
  • Classes are collections of attributes and behaviours based on previously-defined classes.
  • Programmers use inheritance to derive the specific implementation of abstract classes.
  • Classes derived from abstract classes are called derived classes.
  • Principle applied many times in succession results in a hierarchy of classes.

Question 1104

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Describe in Detail

Essay▾

What is Kerberos?

Explanation

Define Kerberos in Image
  • Protocol for authenticating service requests between trusted hosts across an untrusted network like internet.
  • Developed for project Athena at Massachusetts Institute of Technology.
  • Works by requesting an encrypted ticket via an authenticated server sequence to use services.
  • Protocol gets its name from the three headed dog that guarded the gates of Hades in Greek mythology.
  • Uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.
  • The ticket-granting ticket is sent to the ticket-granting server, which is required to use the same authentication server.
  • Ticket is then embedded in message to identify the sender of the message.

Benefits of Kerberos:

  • Delegated authentication.
  • Interoperability.
  • More efficient authentication to server.
  • Mutual authentication.

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