Codebusters Test Learning Standards 5

Question 1

In Codebusters events, what is the standard timed bonus for solving a cipher without using a hint?

Accepted Answer

Teams receive additional time credit subtracted from elapsed solve time

Answer

Teams earn 5 bonus points added to their score

Answer

Teams skip the next cipher automatically

Answer

Teams receive a 10-point difficulty multiplier

Question 2

Which frequency analysis tool looks at pairs of consecutive letters (bigrams) rather than single letters?

Accepted Answer

Digraph frequency analysis

Answer

Monograph analysis

Answer

Index of coincidence

Answer

Kasiski examination

Question 3

What is the Kasiski examination used to detect in a Vigenère-enciphered message?

Accepted Answer

Repeated sequences that reveal the keyword length

Answer

The most common letter in the ciphertext

Answer

Whether the cipher is monoalphabetic or polyalphabetic

Answer

The position of null characters

Question 4

In a columnar transposition with keyword 'MATH' and plaintext 'SCIENCEOLYMPIAD', how many columns are used?

Accepted Answer

4

Answer

3

Answer

5

Answer

6

Question 5

Which of the following is an example of a transposition cipher rather than a substitution cipher?

Accepted Answer

Rail fence cipher

Answer

Caesar cipher

Answer

Vigenère cipher

Answer

Atbash cipher

Question 6

In Codebusters, a 'K4' cipher problem refers to what?

Accepted Answer

A cipher using both a scrambled plain alphabet and a scrambled cipher alphabet with two keywords

Answer

A 4-rail fence transposition

Answer

A Vigenère cipher with a 4-letter key

Answer

A Caesar cipher with shift 4

Question 7

What property makes a one-time pad (OTP) theoretically unbreakable?

Accepted Answer

The key is truly random, as long as the message, and used only once

Answer

The key rotates every 26 characters

Answer

The cipher uses 52-letter alphabets instead of 26

Answer

Multiple substitution tables are layered on top of each other