Codebusters Test Learning Standards 3 — Questions and Answers
Question 1: In a columnar transposition cipher, what determines the order in which columns are read?
- The alphabetical order of the keyword letters (Correct answer)
- The length of each column
- The frequency of letters in each column
- The number of vowels in the keyword
Correct answer: The alphabetical order of the keyword letters
Columns are reordered based on the alphabetical ranking of the keyword's letters (A=1, B=2, etc.).
Question 2: Which cipher type uses two interlocked 'rails' for encipherment, forming a zigzag pattern?
- Rail fence cipher (Correct answer)
- Columnar transposition
- Playfair cipher
- Grille cipher
Correct answer: Rail fence cipher
The rail fence cipher writes plaintext diagonally across a set number of rails, then reads across each rail to produce ciphertext.
Question 3: In Codebusters, what is a 'null' character?
- An inserted character that carries no message content (Correct answer)
- A zero used instead of the letter O
- A repeated letter used to confuse frequency analysis
- A space encoded as a punctuation mark
Correct answer: An inserted character that carries no message content
Null characters are meaningless letters or symbols inserted into ciphertext to disguise the true message length or structure.
Question 4: The Atbash cipher maps A↔Z, B↔Y, C↔X, etc. What kind of cipher is this?
- A monoalphabetic substitution cipher (Correct answer)
- A polyalphabetic substitution cipher
- A transposition cipher
- A symmetric key stream cipher
Correct answer: A monoalphabetic substitution cipher
Atbash is a monoalphabetic substitution cipher where the alphabet is reversed; each letter maps consistently to one other letter.
Question 5: In a Xenocrypt event (Spanish Aristocrat), which Spanish letter pair is particularly important to recognize because it acts as a single unit?
- LL and RR (traditional digraphs) (Correct answer)
- CH and NH
- QU and GU
- ÑO and ÁE
Correct answer: LL and RR (traditional digraphs)
Traditional Spanish treats LL and RR as single letters/digraphs, and recognizing them helps with frequency analysis in Xenocrypt.
Question 6: What is the term for the process of finding the original plaintext from ciphertext without knowing the key?
- Cryptanalysis (Correct answer)
- Encipherment
- Steganography
- Key scheduling
Correct answer: Cryptanalysis
Cryptanalysis is the science of breaking codes and ciphers without possessing the secret key.
Question 7: In the Morbit cipher, what is the basic unit that each symbol represents?
- A Morse code element (dot or dash) for half a letter (Correct answer)
- A full plaintext letter
- A two-letter digraph
- A space between words
Correct answer: A Morse code element (dot or dash) for half a letter
Morbit encodes pairs of Morse code elements (e.g., dot-dot, dot-dash) using a 9-symbol key, making each symbol represent half a Morse character pair.
Codebusters Test Learning Standards 3
In a columnar transposition cipher, what determines the order in which columns are read?