Introduction and History of Cryptography ECES Practice Questions (Page 8)

Questions 36–40

1. 36expert · hard

   A cryptographer is explaining to a colleague why the Vigenère cipher was considered secure for centuries but is now easily broken. Which reason is most accurate?

   • AIt is a transposition cipher, which is inherently insecure.
   • BIt was not widely known, but once the method was published, cryptanalysts developed techniques like the Kasiski examination to break it.
   • CIt uses a fixed key that is too short to provide security.
   • DIt was broken by frequency analysis because it is monoalphabetic.
   Reveal Solution Discussion Select an answer first
2. 37foundation · easy

   Which of the following lists correctly orders major cryptographic milestones from earliest to most recent?

   • AVigenère cipher, Caesar cipher, public-key cryptography, Enigma machine
   • BCaesar cipher, Vigenère cipher, Enigma machine, public-key cryptography
   • CPublic-key cryptography, Enigma machine, Vigenère cipher, Caesar cipher
   • DEnigma machine, Caesar cipher, public-key cryptography, Vigenère cipher
   Reveal Solution Discussion Select an answer first
4. 38expert · hard

   A security trainer is designing a hands-on exercise to demonstrate the weakness of monoalphabetic substitution ciphers. The trainer wants to use a cipher that is easy to implement manually and clearly shows how frequency analysis can break it. The trainer also wants to contrast this with a polyalphabetic cipher that resists simple frequency analysis. Which pair of ciphers should the trainer use?

   • ACaesar cipher and Vigenère cipher
   • BScytale and Caesar cipher
   • CVigenère cipher and Enigma
   • DAtbash and Caesar cipher
   Reveal Solution Discussion Select an answer first
5. 39foundation · easy

   What is the basic mechanism of the Spartan scytale?

   • AIt uses a grid to substitute letters based on a keyword
   • BIt uses a rod of a specific diameter to wrap a strip of parchment and write the message along its length
   • CIt uses a rotating disk with two alphabets to encrypt messages
   • DIt replaces each letter with the letter a fixed number of positions later in the alphabet
   Reveal Solution Discussion Select an answer first
6. 40application · medium

   A history teacher is explaining how ancient ciphers worked. The teacher wants to show a method that used a physical object to perform a transposition of characters, rather than substituting one letter for another. Which ancient cipher should the teacher demonstrate?

   • AThe Atbash cipher
   • BThe Spartan scytale
   • CThe Vigenère cipher
   • DThe Caesar cipher
   Reveal Solution Discussion Select an answer first