Codebusters Test Codebusters Pattern Recognition 5

Question 1

In a Vigenère cipher with keyword 'ACE', which shift is applied to the 4th plaintext letter?

Accepted Answer

0 (key letter A)

Answer

2 (key letter C)

Answer

4 (key letter E)

Answer

1 (key letter B)

Question 2

A student notices ciphertext letter 'J' never appears in a 300-character Aristocrat message. What does this most likely mean?

Accepted Answer

Its corresponding plaintext letter simply never appeared in the original message

Answer

The cipher is definitely polyalphabetic

Answer

J was used as a word separator

Answer

The message contains a deliberate error

Question 3

While solving an Aristocrat, a partial word reads '_HE'. Which letter most commonly fills the blank in English?

Accepted Answer

T

Answer

W

Answer

S

Answer

P

Question 4

In a Morbit cipher (dot=1, dash=2), what two-digit number represents the Morse code for the letter A (dot-dash)?

Accepted Answer

12

Answer

21

Answer

11

Answer

22

Question 5

A Codebusters timed event clue states: 'Caesar shift = number of letters in SCIENCE'. What is the shift value?

Accepted Answer

7

Answer

6

Answer

8

Answer

5

Question 6

Which pattern recognition approach is most universally useful when encountering an UNKNOWN cipher type during Codebusters?

Accepted Answer

Compare the ciphertext letter frequency distribution to standard English frequencies

Answer

Immediately apply ROT13 as the default shift

Answer

Count total characters and divide by 26

Answer

Search for the letter Q as a starting anchor

Question 7

In a columnar transposition cipher, the plaintext 'ATTACK' is written into 3 columns. Reading columns in order 2-1-3, what is the ciphertext?

Accepted Answer

TAATKC

Answer

ATTACK

Answer

TACATK

Answer

AAKTTC