Classical Ciphers (Caesar, Vigenere, Playfair, ADFGVX) ECES Practice Questions (Page 6)

Questions 26–30

1. 26foundation · easy

   In the Vigenere cipher, how is the ciphertext letter determined for a given plaintext letter?

   • ABy converting the plaintext letter to a coordinate pair and then transposing the columns.
   • BBy substituting each plaintext letter with a letter that is a fixed number of positions away in the alphabet.
   • CBy shifting the plaintext letter by a value derived from the corresponding keyword letter.
   • DBy replacing the plaintext letter with a letter from a 5x5 matrix based on its row and column.
   Reveal Solution Discussion Select an answer first
2. 27application · medium

   A student is comparing the Playfair cipher to the Caesar cipher for a class project. Which statement accurately describes a key difference between the two?

   • APlayfair uses a keyword, while Caesar uses a fixed shift
   • BPlayfair is a transposition cipher, while Caesar is a substitution cipher
   • CPlayfair is polyalphabetic, while Caesar is monoalphabetic
   • DPlayfair encrypts digraphs, while Caesar encrypts single letters
   Reveal Solution Discussion Select an answer first
4. 28foundation · easy

   Using a Caesar cipher with a shift of 3, what is the ciphertext for the plaintext 'HELLO'?

   • AKHOOR
   • BGDKKN
   • CEBIIL
   • DMJQQT
   Reveal Solution Discussion Select an answer first
5. 29foundation · easy

   What is the primary historical significance of the Caesar cipher?

   • AIt was the first cipher to use a transposition technique.
   • BIt was the first cipher to be broken using frequency analysis.
   • CIt was the first cipher to use a keyword for polyalphabetic substitution.
   • DIt is one of the earliest known substitution ciphers, used by Julius Caesar for military communications.
   Reveal Solution Discussion Select an answer first
6. 30application · easy

   A puzzle designer wants to create a simple cipher for an escape room. The clue reads 'WKH TXLFN EURZQ IRA' and the designer tells players that it was encrypted with a Caesar cipher. What is the plaintext?

   • ATHE LAZY BROWN FOX
   • BWKH QUICK BROWN FOX
   • CTHE QUICK BROWN DOG
   • DTHE QUICK BROWN FOX
   Reveal Solution Discussion Select an answer first