Oib Part1

49 Questions | Total Attempts: 85

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Computer Network Quizzes & Trivia

Questions and Answers
  • 1. 
    What is the purpose of Passive Attack?
    • A. 

      A)To counter security attacks, and they make use of one or more security mechanisms to provide the service.

    • B. 

      B)To learn or make use of information from the system but does not affect system resources

    • C. 

      C)To provide timeliness of authorisation to use or manipulate information or resources

    • D. 

      D)To bind information to an entity

    • E. 

      E)To alter system resources or affect their operation.

  • 2. 
      Choose the definition of Security mechanism?
    • A. 

      A) A potential for violation of security, which exists when there is a circumstance, capability, action, or event that could breach security and cause harm.

    • B. 

      B) Any action that compromises the security of information owned by an organization

    • C. 

      C) All of the statement

    • D. 

      D) A processing or communication service that enhances the security of the data processing systems and the information transfers of an organization.

    • E. 

      E) A process that is designed to detect, prevent, or recover from a security attack.

  • 3. 
    Given that the Caesar’s cipher is used, find the plaintext from the ciphertext. ZKDW GRHV WKH IRA VDB. 
    • A. 

      What does the fox say.

    • B. 

      Option 2

  • 4. 
      The conversion of plaintext or data into unintelligible form by means of a reversible translation, based on a translation table or algorithm
    • A. 

      A) Deciphering

    • B. 

      B) Decryption

    • C. 

      C) All of the statement

    • D. 

      D) Encryption

    • E. 

      E) Enciphering

  • 5. 
    What is the functionality of a block-cipher?
    • A. 

      A) processes the input elements continuously, producing output one element at a time, as it goes along

    • B. 

      B) A procedure used during symmetric block encryption that makes an output block dependent not only on the current plaintext input block and key, but also on earlier input and/or output.

    • C. 

      C) processes the input one block of elements at a time, producing an output block for each input block.

    • D. 

      D) exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used

    • E. 

      E) verification the integrity of a message

  • 6. 
    A two-letter sequence is called ______________.
    • A. 

      A) None of the statements

    • B. 

      B) Letter

    • C. 

      C) Twogram

    • D. 

      D) Bigram

    • E. 

      E) Digram

  • 7. 
    The translation of encrypted text or data into original text or data
    • A. 

      A) Decryption

    • B. 

      B) Enciphering

    • C. 

      C) All of the statements

    • D. 

      D) Deciphering

    • E. 

      E) Encryption

  • 8. 
    Choose the definition of Security service?
    • A. 

      A) All of the statements

    • B. 

      B) A process that is designed to detect, prevent, or recover from a security attack.

    • C. 

      C) A processing or communication service that enhances the security of the data processing systems and the information transfers of an organization.

    • D. 

      D) A potential for violation of security, which exists when there is a circumstance, capability, action, or event that could breach security and cause harm.

    • E. 

      E) Any action that compromises the security of information owned by an organization

  • 9. 
    What is a Masquerade?
    • A. 

      A) Preventing or inhibiting the normal use or management of communications facilities

    • B. 

      B) The passive capturing of a data unit and its subsequent retransmission to produce an unauthorized effect

    • C. 

      C) One entity pretends to be a different entity

    • D. 

      D) Restricting access to resources to privileged entities.

    • E. 

      E) Altering some portion of a legitimate message, or that messages are delayed or reordered, to produce an unauthorized effect

  • 10. 
    The output of an encryption algorithm; the encrypted form of a message or data
    • A. 

      A) Cipher

    • B. 

      B) Encryption

    • C. 

      C) Plaintext

    • D. 

      D) Ciphertext

    • E. 

      E) Decryption

  • 11. 
    In which of the four basic password techniques the system periodically runs its own password cracker to find guessable passwords and cancels any passwords that are guessed and notifies the user
    • A. 

      A) User education

    • B. 

      B) Reactive password checking

    • C. 

      C) User-generated passwords

    • D. 

      D) Computer-generated passwords

    • E. 

      E) Proactive password checking

  • 12. 
    Indicate the drawbacks of reactive password checking technique
    • A. 

      A) resource intensive

    • B. 

      B) Others may not be good judges of what is a strong password.

    • C. 

      C) users will not be able to remember them

    • D. 

      D) any existing passwords remain vulnerable

    • E. 

      E) many users will simply ignore the guidelines.

  • 13. 
    A legitimate user who accesses data, programs, or resources for which such access is not authorized, or who is authorized for such access but misuses his or her privileges
    • A. 

      A) Masquerader

    • B. 

      B) Crypto analyzer

    • C. 

      C) Misfeasor

    • D. 

      D) Clandestine user

    • E. 

      E) Cryptologist

  • 14. 
    An individual who is not authorized to use the computer and who penetrates a system's access controls to exploit a legitimate user's account
    • A. 

      A) Masquerader

    • B. 

      B) Misfeasor

    • C. 

      C) Cryptologist

    • D. 

      D) Clandestine user

    • E. 

      E) Crypto analyzer

  • 15. 
    An authentication mechanism that enables the creator of a message to attach a code that acts as a signature.
    • A. 

      A) Hybrid Cryptosystem

    • B. 

      B) Diffusion

    • C. 

      C) Diffie-Hellman Algorithm

    • D. 

      D) Digital signature

    • E. 

      E) Man-in-the-middle attack

  • 16. 
    Which of these is a mixing algorithm?
    • A. 

      A) AES

    • B. 

      B) RC4

    • C. 

      C) RSA

    • D. 

      D) DES

    • E. 

      E) SHA1

  • 17. 
    Indicate the one of the purposes of salt used in the Unix password scheme
    • A. 

      A) It effectively increases the length of the password without requiring the user to remember two additional characters.

    • B. 

      B) It prevents password from being corrupted by intruders.

    • C. 

      C) It prevents the users from creating passwords.

    • D. 

      D) It effectively decreases the length of the password without requiring the user to remember two additional characters.

    • E. 

      E) It is used as a secret key for encryption password.

  • 18. 
    In which of the four basic password techniques users can be told the importance of using hard-to-guess passwords and can be provided with guidelines for selecting strong passwords
    • A. 

      A) Computer-generated passwords

    • B. 

      B) Reactive password checking

    • C. 

      C) Proactive password checking

    • D. 

      D) User education

    • E. 

      E) User-generated passwords

  • 19. 
    Indicate the one of the purposes of salt used in the Unix password scheme
    • A. 

      A) It effectively decreases the length of the password without requiring the user to remember two additional characters

    • B. 

      B) It prevents the users from creating passwords.

    • C. 

      C) It prevents password from being corrupted by intruders

    • D. 

      D) It prevents duplicate passwords from being visible in the password file

    • E. 

      E) It is used as a secret key for encryption password.

  • 20. 
    In which of the four basic password techniques a user is allowed to select his or her own password. At the time of selection, the system checks to see if the password is allowable and, if not, rejects it
    • A. 

      A) User education

    • B. 

      B) Proactive password checking

    • C. 

      C) User-generated passwords

    • D. 

      D) Reactive password checking

    • E. 

      E) Computer-generated passwords

  • 21. 
    Which of these types of cipher is most suitable to encrypt verbal communication via mobile phone?
    • A. 

      A) Stream

    • B. 

      B) Asymmetric

    • C. 

      C) Block

    • D. 

      D) Classical

    • E. 

      E) Public-key

  • 22. 
       If a wrong key is entered to decrypt a message, what will happen?
    • A. 

      A) The cryptosystem will stop working

    • B. 

      B) the output will be gibberish

    • C. 

      C) There is an error message

    • D. 

      D) Nothing will happen

    • E. 

      E) The output will not be visible

  • 23. 
    Suppose that your plaintext is 130 bytes long and you are using DES, how many blocks will be formed for the whole encryption process?
    • A. 

      A) 8

    • B. 

      B) 17

    • C. 

      C) 16

    • D. 

      D) 0

    • E. 

      E) 9

  • 24. 
    Suppose that your plaintext is 115 bytes long and you are using RC4, how many bytes are needed for padding?
    • A. 

      A) 8

    • B. 

      B) RC4 does not need padding

    • C. 

      C) Depends on the size of the block

    • D. 

      D) 2

    • E. 

      E) 4

  • 25. 
    Which of these statements is TRUE?
    • A. 

      A) In symmetric-key cryptography, the key that is used to encrypt data is the same key that is used to decrypt it

    • B. 

      B) In cryptography, to protect the contents of your files, you install a lock (a decryption algorithm) on your door (the computer).

    • C. 

      C) The term “key” comes from the fact that the password you choose works in the same way that a conventional key works

    • D. 

      D) The encryption algorithm performs its steps using the key to alter the ciphertext and convert it to plaintext

    • E. 

      E) The decryption algorithm performs its steps using the key to alter the plaintext and convert it to ciphertext