Codebusters Test Codebusters Transposition Ciphers 1

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

Transposition ciphers rearrange the positions of plaintext letters without substituting them, so the same alphabet of letters appears but in a different order.

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

The rail fence cipher writes plaintext letters diagonally up and down across a set number of rails, then reads off each rail left to right to produce the ciphertext.

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

Since transposition only rearranges letters without changing them, each letter appears exactly as often in the ciphertext as in the plaintext, so frequency analysis reveals English-like frequencies rather than exposing the key.

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

Columnar transposition writes the plaintext across rows in a rectangular grid, then reads out the columns in the order dictated by alphabetizing the keyword letters.

Question 5

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

Accepted Answer

The scytale

Answer

The scytale, used by ancient Spartans, was a cylinder around which a leather strip was wound; the message written across the strip was only readable when wound around a cylinder of the same diameter.

Codebusters Test Practice Test

Codebusters Test Practice Test

Codebusters Test Codebusters Transposition Ciphers 1