Codebusters Test Learning Standards 2

Question 1

In a Patristocrat cipher, how is the plaintext formatted before encipherment?

Accepted Answer

Letters are grouped into 5-character blocks with spaces removed

Answer

Words are separated by slashes

Answer

Each word is reversed individually

Answer

Spaces are replaced with underscores

Question 2

What is the Index of Coincidence (IC) used for in Codebusters?

Accepted Answer

To estimate the key length of a polyalphabetic cipher

Answer

To count the number of unique letters in ciphertext

Answer

To determine the Caesar shift value

Answer

To identify null characters in a transposition cipher

Question 3

In a Vigenère cipher with keyword 'CAT', what shift is applied to the second plaintext letter?

Accepted Answer

0 (A=0)

Answer

2 (C=2)

Answer

19 (T=19)

Answer

1 (B=1)

Question 4

Which letter is statistically the most frequent in standard English text?

Accepted Answer

E

Answer

T

Answer

A

Answer

O

Question 5

A Baconian cipher encodes each plaintext letter using how many binary-like symbols?

Accepted Answer

5

Answer

4

Answer

6

Answer

8

Question 6

In an Aristocrat cipher, what key advantage does the solver have over a Patristocrat?

Accepted Answer

Word boundaries and spaces are preserved

Answer

The key is provided at the start

Answer

Numbers replace vowels

Answer

Only consonants are enciphered

Question 7

What does a Caesar cipher with a shift of 13 produce, and what is this special case called?

Accepted Answer

ROT13, a self-inverse cipher

Answer

Atbash, a mirror cipher

Answer

Null cipher, unreadable output

Answer

Rail fence, a transposition