FREE Codebusters Cipher Decryption Questions and Answers
In a substitution cipher, the letter "L" has been replaced by the letter "X" in the ciphertext. What is this process called?
In a substitution cipher, each letter of the plaintext is replaced by another letter (in this case, "L" becomes "X"). This process is called substitution, where the letters of the alphabet are systematically replaced by others.
If a message is encoded with a Vigenère cipher using the keyword "KEY," what would be the first letter of the decrypted message if the ciphered letter is "F"?
In the Vigenère cipher, the key repeats across the message. "K" corresponds to a shift of 10, "E" to a shift of 4, and "Y" to a shift of 24. Since the first letter in the ciphertext is "F," the shift is from the letter "K," which shifts "F" back by 10 letters, giving "E."
Which of the following ciphers is based on shifting the alphabet by a fixed number of positions?
The Caesar cipher involves shifting each letter in the plaintext by a fixed number of positions in the alphabet. For example, with a shift of 3, "A" becomes "D," "B" becomes "E," and so on.
Using the Atbash cipher, what is the decryption of the letter "M"?
The Atbash cipher is a type of substitution cipher where the alphabet is reversed. "A" becomes "Z," "B" becomes "Y," and so on. The letter "M" becomes "N" when using the Atbash cipher because it is the 13th letter in the alphabet, and its reverse counterpart is also the 13th letter from the end.
Which of the following is the correct decryption of the cipher "Wklv lv d whvw phvvdjh." using a Caesar cipher with a shift of 3?
A Caesar cipher with a shift of 3 means each letter is shifted 3 positions backward in the alphabet. When decrypting "Wklv lv d whvw phvvdjh," shifting each letter 3 positions back gives "This is a test message."