Playfair Cipher

Classic digraph substitution cipher using a 5 by 5 square.

The Playfair cipher was the first practical digraph substitution cipher. It encrypts pairs of letters instead of single letters. Usually J is merged with I, but you can customize the switched letter in Alphabet Options.

Plaintext

Alphabet

Enter a keyword, phrase, or alphabet and the rest will be calculated for you.

This cipher only has 25 characters, so one character must be switched.

Switch

Into

Keyword or phrase

Use last instance of keyword letters Reverse keyword Put keyword on right side Reverse alphabet portion Randomize alphabet Reverse final result

Pad Character

Ciphertext

Playfair Cipher

Polybius Square