Autokey Cipher
The Autokey Cipher, invented by Blaise de Vigenère in the 16th century, is a form of polyalphabetic substitution cipher that improves on the traditional Vigenère cipher by incorporating the plaintext itself into the key. This cipher was designed to strengthen encryption by reducing repetitive patterns in the key, making it more resistant to frequency analysis. The concept of the Autokey Cipher builds on Vigenère's previous work and is part of what’s sometimes called the Vigenère family of ciphers.
Atbash Cipher
In the Atbash cipher:
Affine Cipher
The Affine cipher is a type of substitution cipher rooted in modular arithmetic, which falls under the category of monoalphabetic ciphers. It has origins in classical cryptography, dating back to the use of basic substitution techniques by ancient civilizations.
A1Z26
The A1Z26 cipher, also known as the letter-number cipher or the alphabet cipher, is a simple substitution cipher where each letter of the alphabet is replaced with its corresponding position number.
In the A1Z26 cipher:
The letter A is represented by the number 1.
The letter B is represented by the number 2.
The letter C is represented by the number 3.