A tool employing linear algebra to encrypt and decrypt text, this method transforms plaintext into ciphertext using matrix multiplication based on a chosen key. For example, a key in the form of a matrix operates on blocks of letters (represented numerically) to produce encrypted blocks. Decryption involves using the inverse of the key matrix.
This matrix-based encryption method offers stronger security than simpler substitution ciphers due to its polygraphic nature, meaning it encrypts multiple letters simultaneously, obscuring individual letter frequencies. Developed by Lester S. Hill in 1929, it was one of the first practical polygraphic ciphers. Its reliance on linear algebra makes it adaptable to different key sizes, offering flexibility in security levels. Understanding the mathematical underpinnings provides insights into both its strengths and limitations in the context of modern cryptography.
