TechFinity toolkit
Playfair Cipher
Classical digraph substitution cipher. Educational use only.
Input
Rules (encode): split into digraphs; if a pair has same letters, insert pad after first; if odd length, pad the last. Same row: shift right. Same column: shift down. Rectangle: swap columns.
Key Square
| A | B | C | D | E |
| F | G | H | I | K |
| L | M | N | O | P |
| Q | R | S | T | U |
| V | W | X | Y | Z |