Playfair Cipher client-side ?
How to use Playfair CipherThe Playfair cipher encrypts letters two at a time (digraphs) using a 5×5 grid built from a keyword — letters I and J sharing a cell. For each pair, three rules apply based on the letters' positions in the grid: on the same row, take the letter to the right; on the same column, the one below; otherwise form a rectangle and swap columns. Enter a keyword and your text to encrypt or decrypt, and watch the generated grid. Educational tool, processed client-side.
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The Playfair cipher encrypts letters two at a time (digraphs) using a 5×5 grid built from a keyword — letters I and J sharing a cell. For each pair, three rules apply based on the letters' positions in the grid: on the same row, take the letter to the right; on the same column, the one below; otherwise form a rectangle and swap columns. Enter a keyword and your text to encrypt or decrypt, and watch the generated grid. Educational tool, processed client-side.
Digraph cipher with a 5×5 key square.
How to use Playfair Cipher
The Playfair cipher encrypts letters two at a time (digraphs) using a 5×5 grid built from a keyword — letters I and J sharing a cell. For each pair, three rules apply based on the letters' positions in the grid: on the same row, take the letter to the right; on the same column, the one below; otherwise form a rectangle and swap columns. Enter a keyword and your text to encrypt or decrypt, and watch the generated grid. Educational tool, processed client-side.
Frequently asked questions
Why are I and J merged?
To fit the 26 letters into a 25-cell (5×5) grid. On decryption an I can therefore stand for I or J, to be read from context.
What happens with a pair of identical letters?
A filler letter (often X) is inserted between them, since Playfair cannot encrypt a pair of equal letters.