Interactive cryptography tools

Shift plaintext letters by a fixed number of positions.

Encrypt text with E(x) = (ax + b) mod 26 using configurable keys and formatting options.

Build a keyed substitution alphabet from a cleaned keyword.

Polyalphabetic substitution cipher using a repeating key.

Use a repeating keyword with the reciprocal Beaufort rule C = K - P mod 26.

Extend a keyword with plaintext letters for a stronger polyalphabetic stream.

Encrypt letter pairs with a 5×5 keyword square and digraph rules.

Encrypt letter blocks with square key matrices and modular arithmetic.

Encode letters as row-and-column coordinates using the classic 5x5 Polybius square.

Mix Polybius square coordinates in fixed-size blocks to create a fractionating classical cipher.

Use a keyed ADFGX square followed by keyed columnar transposition.

Use a keyed ADFGVX square with letters and digits, then apply keyed columnar transposition.