Playfair Cipher Lab
Comprehensive tool for teaching digraph preparation and 5×5 matrix rules.
Secret Keyword
Message to Encrypt
Live 5 × 5 Matrix
Process Message
Padding Rules (Fillers)
01
Repeating:
If a pair is "EE", add "X" → "EX", "E...". If the repeat is "XX", use "Q" instead.
02
Odd Length:
If the message has an odd number of letters, add "X" (or "Q" if the last is "X") to the end.
03
The 'J' Rule:
'J' is always replaced by 'I' before processing.
1
Digraph (Pair) Preparation
2
Encryption Walkthrough
3
Decryption Walkthrough