Exercises 41 In a Polybius cipher each letter is enciphered

Exercises 41: In a Polybius cipher, each letter is enciphered as two integers. The key is a 5×5 matrix of characters as in a Playfair cipher. The plaintext is the character in the matrix, the ciphertext is the two integers (each between 1 and 5) representing row and column numbers. Encipher the message “ An exercise” using the Polybius cipher with the following key:

Solution

The encrypted text is as follows using the following key:

a=55

n=33 and so on

5533 1531152235443215