Classical Encryption Techniques Quiz
30 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What term is used for the original message before encryption?

  • Cipher
  • Key
  • Plaintext (correct)
  • Ciphertext

    • Which encryption type was the only one in use before the introduction of asymmetric encryption?

  • Public-key encryption
  • Symmetric encryption (correct)
  • Conventional encryption
  • Cryptanalysis

    • What is the term for the study of principles/methods of deciphering ciphertext without knowing the key?

  • Cryptology (correct)
  • Ciphertext analysis
  • Symmetric encryption
  • Decryption

    • Who first publicly proposed Public-key encryption?

    <p>Diffie and Hellman</p> Signup and view all the answers

    What does cryptanalysis involve?

    <p>Deciphering ciphertext without the key</p> Signup and view all the answers

    What does encipher refer to in cryptography?

    <p>Converting plaintext to ciphertext</p> Signup and view all the answers

    What is a characteristic of the Vigenère cipher?

    <p>Requires a 26x26 table with letters A to Z</p> Signup and view all the answers

    What is the purpose of repeating the keyword in the Vigenère cipher?

    <p>To match the length of the plaintext</p> Signup and view all the answers

    Who invented the Playfair Cipher?

    <p>Charles Wheatstone</p> Signup and view all the answers

    What is the key matrix in the Playfair Cipher based on?

    <p>A keyword without duplicates</p> Signup and view all the answers

    How does the Playfair Cipher handle repeated letters in encryption?

    <p>It replaces repeated letters with filler like 'X'</p> Signup and view all the answers

    Which cipher is known for encrypting multiple letters at once to improve security?

    <p>Playfair Cipher</p> Signup and view all the answers

    What is the main difference between public-key cryptography and symmetric key encryption?

    <p>Public-key cryptography uses two separate keys while symmetric key encryption uses only one key.</p> Signup and view all the answers

    Which of the following is NOT a consequence of using two keys in public-key cryptography?

    <p>Decreased key security</p> Signup and view all the answers

    What is the general goal of cryptanalytic attacks?

    <p>To recover the encrypted message</p> Signup and view all the answers

    How does a brute-force attack differ from a cryptanalytic attack?

    <p>A brute-force attack tries every possible key until an intelligible translation is obtained, while a cryptanalytic attack relies on algorithm characteristics.</p> Signup and view all the answers

    What factor determines the time required for a brute-force attack?

    <p>The number of alternative keys available</p> Signup and view all the answers

    How does the time required for a brute-force attack change with an increase in key size?

    <p>The time required increases exponentially with the key size.</p> Signup and view all the answers

    What is the mathematical representation of the Caesar cipher transformation?

    <p>c = E(p) = (p + k) mod (26)</p> Signup and view all the answers

    What is the main disadvantage of the Caesar cipher in terms of security?

    <p>It has only 25 possible keys</p> Signup and view all the answers

    In cryptanalysis of the Caesar cipher, what method can be used to decode the ciphertext?

    <p>Brute force search</p> Signup and view all the answers

    What technique involves replacing plaintext letters with other letters, numbers, or symbols?

    <p>Classical substitution cipher</p> Signup and view all the answers

    How many characters are there in a permutation of a finite set of elements?

    <p>26</p> Signup and view all the answers

    What transformation replaces each letter with the 3rd letter that follows it in the alphabet?

    <p>Caesar cipher</p> Signup and view all the answers

    How many permutations are there for a set with elements {a, b, c}?

    <p>6 permutations</p> Signup and view all the answers

    What does a monoalphabetic cipher do?

    <p>Maps each plaintext letter to a random ciphertext letter</p> Signup and view all the answers

    Why is it incorrect to assume that a monoalphabetic cipher with 26! keys is secure?

    <p>Language characteristics and redundancy make decryption easy</p> Signup and view all the answers

    What is one of the reasons why English text is vulnerable to cryptanalysis?

    <p>The absence of common letters like E, T, R, N in English</p> Signup and view all the answers

    In the given ciphertext 'UZQSOVUOHXMOPVGPOZPEVSGZWSZOPFPESXUDBMETSXAIZ', what letters are most likely to represent 'e' and 't'?

    <p>'P' and 'Z'</p> Signup and view all the answers

    What is the main challenge faced in cryptanalysis when analyzing the given ciphertext?

    <p>Dealing with language characteristics like letter frequencies and redundancy</p> Signup and view all the answers

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser