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

Codebusters scoring rewards faster solutions; bonus time is effectively a reduction in the recorded solve time when no hints are used.

Question 2

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

Accepted Answer

Digraph frequency analysis

Answer

Digraph (bigram) frequency analysis examines pairs of letters; common English digraphs like TH, HE, and IN help break substitution ciphers.

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

Kasiski examination finds repeated ciphertext sequences; the distances between them are likely multiples of the keyword length.

Question 4

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

Accepted Answer

4

Answer

The number of columns equals the number of letters in the keyword; 'MATH' has 4 letters, so 4 columns are used.

Question 5

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

Accepted Answer

Rail fence cipher

Answer

The rail fence cipher rearranges the positions of letters without changing them; transposition ciphers permute rather than substitute.

Codebusters Test Practice Test