Classical Cryptography Workbench

CipherLab

Encrypt, decrypt, and inspect every step behind Caesar, Vigenere, Affine, Hill, and Playfair ciphers.

Session history

Recent operations

No encryption or decryption history yet.

C

Monoalphabetic shift

Caesar Cipher

Formula: E(x) = (x + k) mod 26, D(y) = (y - k) mod 26

Mode

Input Text *

Shift Value *

Encrypted Output

Run Caesar to see the shift formula and character-by-character steps.

V

Polyalphabetic keyword

Vigenere Cipher

Formula: E(x) = (x + k_i) mod 26, D(y) = (y - k_i) mod 26

Mode

Input Text *

Keyword *

Encrypted Output

Run Vigenere to see keyword shifts aligned with each letter.

A

Linear substitution

Affine Cipher

Formula: E(x) = (ax + b) mod 26, D(y) = a^-1(y - b) mod 26

Mode

Input Text *

Key a *

Key b *

Valid a values: 1, 3, 5, 7, 9, 11, 15, 17, 19, 21, 23, 25

Encrypted Output

Run Affine to see modular arithmetic for each transformed letter.

H

Matrix polygraphic cipher

Hill Cipher

Formula: C = K x P mod 26 for a 2x2 key matrix

Mode

Matrix Size

Input Text *

Key Matrix 2x2 *

det(K) = ad - bc must be coprime with 26.

Encrypted Output

Run Hill to see the key matrix, vectors, and multiplication modulo 26.

P

Digraph substitution

Playfair Cipher

Rules: same row shifts horizontally, same column shifts vertically, rectangle swaps columns.

Mode

Input Text *

Keyword *

Encrypted Output

Run Playfair to see the 5x5 table, letter pairs, and rule used per pair.