The Hill cipher is a cryptographic method developed by mathematician Lester S. Hill in 1929. It is based on linear algebra and uses matrices to transform blocks of plaintext into ciphertext.

1. Define your alphabet in the first field.
2. Enter a key text (at least 4 characters). The matrix size is derived from the square root of its length.
3. Enter the text you want to encrypt or decrypt.
4. The results appear automatically.

Character table

Cipher matrix (MC)

Message matrices

MC × Matrices

MC inverse

MC⁻¹ × Matrices