Codebusters Test Codebusters Transposition Ciphers

Question 1

What is the defining characteristic of a transposition cipher?

Accepted Answer

The positions of letters are rearranged without changing the letters themselves

Answer

Letters are replaced with different letters using a fixed alphabet

Answer

Each letter is shifted by a numeric key value

Answer

Letters are converted into pairs of symbols using a grid

Question 2

How does the rail fence cipher encipher a message?

Accepted Answer

It writes the plaintext in a zigzag pattern across multiple rails and reads off each rail in sequence

Answer

It shifts each letter by the number of its rail position

Answer

It fills columns with plaintext and reorders them using a keyword

Answer

It writes the message in reverse along a diagonal path

Question 3

Why is frequency analysis alone insufficient to break a transposition cipher?

Accepted Answer

Transposition preserves letter frequencies, so the distribution looks like normal English

Answer

Transposition ciphers eliminate repeated letters

Answer

Transposition ciphers always produce a flat frequency distribution

Answer

Frequency analysis only applies to polyalphabetic ciphers

Question 4

In a columnar transposition cipher, how is the ciphertext generated?

Accepted Answer

The plaintext is written row by row into a grid and the columns are read out in a key-determined order

Answer

The plaintext is written in a single column and read diagonally

Answer

The plaintext is written column by column and rows are read in a keyword order

Answer

Each column is individually encrypted with the corresponding keyword letter

Question 5

What ancient cipher device used a cylinder to implement a transposition cipher?

Accepted Answer

The scytale

Answer

The Polybius square

Answer

The Enigma rotor

Answer

The Jefferson wheel

Question 6

What is the route cipher?

Accepted Answer

A cipher where plaintext is written into a grid and read out following a specified geometric path

Answer

A cipher where letters travel through a series of substitution tables

Answer

A cipher that routes letters through multiple transposition stages simultaneously

Answer

A cipher based on reading alternate letters from the plaintext

Question 7

If the index of coincidence (IC) of a ciphertext is approximately 0.065, what does this suggest?

Accepted Answer

The cipher is most likely a transposition or monoalphabetic substitution cipher

Answer

The cipher is a polyalphabetic substitution like Vigenère

Answer

The cipher has a very short keyword

Answer

The cipher uses a completely random key