Codebusters Test Codebusters Cipher Decryption 4

Question 1

In an Aristocrat cipher, a three-letter ciphertext word appears far more frequently than any other. Which English plaintext word is it most likely to be?

Accepted Answer

THE

Answer

AND

Answer

FOR

Answer

NOT

Question 2

In an Aristocrat, a single-letter ciphertext word can only decrypt to which letters?

Accepted Answer

A or I

Answer

A, I, or O

Answer

Any vowel

Answer

A, I, or E

Question 3

Which letter is the most common word-initial letter in English, making it a key target when identifying word beginnings in an Aristocrat?

Accepted Answer

T

Answer

E

Answer

A

Answer

S

Question 4

After establishing X=T and Y=H in an Aristocrat, the frequent three-letter word 'XYZ' almost certainly decrypts to:

Accepted Answer

THE

Answer

THY

Answer

TAX

Answer

TEN

Question 5

Which category of doubled-letter patterns is most useful when scanning an Aristocrat for doubled-letter clues?

Accepted Answer

LL, SS, EE, OO

Answer

TH, HE, IN, ER

Answer

Single-letter words A, I

Answer

QU combinations

Question 6

In an Aristocrat, spotting a two-letter word where both ciphertext letters differ narrows the plaintext to which group of common words?

Accepted Answer

OF, TO, IN, IS

Answer

AA, BB, CC, DD

Answer

QU, GH, PH, WH

Answer

TH, HE, ER, AN

Question 7

When solving a Patristocrat (Aristocrat without word spaces), what is the most effective first step?

Accepted Answer

Perform letter frequency analysis and search for common digraph patterns

Answer

Guess the cipher keyword

Answer

Count the total number of ciphertext letters

Answer

Look for doubled letters at the ends of groups