Oib Part4

35 Questions | Total Attempts: 46

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Computer Network Quizzes & Trivia

Questions and Answers
  • 1. 
    An algorithm for encryption and decryption. Replaces a piece of information (an  element in plaintext) with another object, with the intent to conceal meaning.   
    • A. 

      Cipher

    • B. 

      Ciphertext

    • C. 

      Decryption

    • D. 

      Encryption

  • 2. 
    Suppose that your plaintext is 168 bytes long and you are using DES,  how many blocks will be formed for the whole encryption process?   
    • A. 

      21

    • B. 

      23

    • C. 

      11

    • D. 

      212

  • 3. 
    Which of these is possibly the best password that user can choose
    • A. 

      14G:c*%3wM*-l6g_Bnp?d86

    • B. 

      ALm4tyc?TY

    • C. 

      Nursultan1612

    • D. 

      Option 4

  • 4. 
    Which of these is not considered a symmetric-key algorithm   
    • A. 

      Vigenerecipher

    • B. 

      RC4

    • C. 

      Caesarcipher

    • D. 

      RSA

  • 5. 
    Point out two major advantages of public crypto over symmetric key  crypto
    • A. 

      Digital signatures offer only integrity

    • B. 

      With public key crypto, we don‟t need to established a shared key in advance

    • C. 

      Digital signatures offer not only integrity but also non-repudiation

    • D. 

      With public key crypto, we need to established a shared key in advance

  • 6. 
    A _____________ is the one-way function, since it is not practical to  reverse
    • A. 

      Roundfunction

    • B. 

      FeistelCipher

    • C. 

      DES

    • D. 

      MessageDigest

  • 7. 
    If you encrypt a ciphertext using the right key, you will get   
    • A. 

      Theplaintext

    • B. 

      Gibberish

    • C. 

      Errormessage

    • D. 

      Option 4

  • 8. 
    Which of these statements is NOT TRUE 
    • A. 

      It is impossible to break an encryption without a key

    • B. 

      It is possible to try all possible numbers systematically to break the encryption

    • C. 

      Without a key, if hackers are able to obtain the encrypted file, it is possible that they can obtain the program that converts it back

    • D. 

      Even though someone can use the same program used to encrypt the file, it can never re-creates the original file without the secret numb Even though someone can use the same program used to encrypt the file, it can never re-creates the original file without the secret numb

  • 9. 
    Operation which maps elements of the plaintext into another is known  as ___________.   
    • A. 

      Noneofthestatements

    • B. 

      Transposition

    • C. 

      Rearranging

    • D. 

      Substitution

  • 10. 
    A form of active wiretapping attack in which the attacker intercepts  and selectively modifies communicated data in order to masquerade as  one or more of the entities involved in a communication.
    • A. 

      Mandatoryaccesscontrol

    • B. 

      Noneofthestatements

    • C. 

      Intrusiondetectionsystem

    • D. 

      Man-in-the-middleattack

  • 11. 
    What is a Modification of messages   
    • A. 

      Preventing or inhibiting the normal use or management of communications facilities

    • B. 

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

    • C. 

      Restricting access to resources to privileged entities.

    • D. 

      . One entity pretends to be a different entity

  • 12. 
    Indicate the definition for Signature
    • A. 

      Corroborating the source of information; also known as data origin authentication.

    • B. 

      Keeping information secret from all but those who are authorised to see it

    • C. 

      Ensuring information has not been altered by unauthorised or unknown means

    • D. 

      Binding information to an entity

  • 13. 
    Indicate the drawbacks of reactive password checking technique
    • A. 

      Any existing passwords remain vulnerable

    • B. 

      Resourceintensive

    • C. 

      Many users will simply ignore the guidelines.

    • D. 

      Users will not be able to remember them

  • 14. 
    Using the Vigenère cipher, encrypt the word "expla" using the key leg 
    • A. 

      Pbvwe

    • B. 

      Option 2

    • C. 

      Option 3

    • D. 

      Option 4

  • 15. 
    A function that is easily computed, but the calculation of its inverse is infeasible
    • A. 

      One-wayfunction

    • B. 

      RC4

    • C. 

      DES

    • D. 

      RSA

  • 16. 
    Which of the following statement is NOT TRUE ( 99%)
    • A. 

      RSA encrypts at a speed on par with symmetric cryptosystems

    • B. 

      . No efficient algorithm exists for solving the RSA ciphertext problem

    • C. 

      . Some experts believe that RSA 1024-bit keys may become breakable in the near term

    • D. 

      All of the listed answers are TRUE

  • 17. 
    Indicate the definition for Privacy or confidentiality   
    • A. 

      Keeping information secret from all but those who are authorised to see it

    • B. 

      Ensuring information has not been altered by unauthorised or unknown means

    • C. 

      Corroborating the source of information; also known as data origin

    • D. 

      Binding information to an entity

  • 18. 
    Which of the following are examples of the host dependent malicious programs   
    • A. 

      Trapdoor

    • B. 

      LogicBombs

    • C. 

      TrojanHorses

    • D. 

      Rootkit

  • 19. 
    Which malicious software is used to cause DoS (Denial of Service) attack against particular  web site   
    • A. 

      Keylogger

    • B. 

      TrojanHorse

    • C. 

      WORM

    • D. 

      Zombie

  • 20. 
    An attack on the key by attempting all possible combinations is called   
    • A. 

      A cryptographic key attack

    • B. 

      A brute force attack

    • C. 

      An all combinations attack

    • D. 

      A random key attack

  • 21. 
    What is the purpose of Active Attack
    • A. 

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

    • B. 

      To alter system resources or affect their operation.

    • C. 

      To bind information to an entity

    • D. 

      Option 4

  • 22. 
    What is the key length in DES
    • A. 

      48-bit

    • B. 

      256-bit

    • C. 

      56-bit

    • D. 

      64-bit

  • 23. 
    Indicate the definition for Access control
    • A. 

      Recording the time of creation or existence of information

    • B. 

      Conveyance, to another entity, of official sanction to do or be something

    • C. 

      Endorsement of information by a trusted entity

    • D. 

      Restricting access to resources to privileged entities

  • 24. 
    Which of the following statement is TRUE
    • A. 

      Public-key algorithms are susceptible to dictionary attack

    • B. 

      The fastest technique to break public-key algorithms is brute force

    • C. 

      No one has been able to develop a public-key algorithm that has no weaknesses

    • D. 

      Public-key algorithms are suitable to encrypt large data

  • 25. 
    Indicate the definition for Authorisation   
    • A. 

      Providing timeliness of authorisation to use or manipulate information or resources

    • B. 

      Restricting access to resources to privileged entities

    • C. 

      Endorsement of information by a trusted entity

    • D. 

      . conveyance, to another entity, of official sanction to do or be something