The Italian scholar and artist Leon Battista Alberti, famed as the first Renaissance man, invented the Cipher wheel, circa 1466. This being the first use of a polyalphabetic coding system. Alberti also wrote the first known frequency table, which enabled cryptanalysts to decipher messages based on the frequency or rarity of various letters.
The device was simply two attached copper circles, The large fixed wheel displaying the alphabet plus the Numbers 1 through 4, and a small movable wheel which displayed a randomly rearranged version of the alphabet. The cipher could be shifted frequently while encoding a message, thus making it very difficult to decipher a message. The four Numbers were used to place enciphered codes into the message.
Leon Battista Alberti
- Leon Battista Alberti – Wikipedia
Leon Battista Alberti was born in 1404 in Genoa. His mother is unknown, and his father was a wealthy Florentine who had been exiled from his own city, allowed to return in 1428.
- Alberti cipher disk – Wikipedia
The Alberti cipher disk, also called formula, is a cipher disc which was described by Leon Battista Alberti in his treatise De Cifris of 1467.
- Alberti cipher – Wikipedia
The Alberti Cipher was one of the first polyalphabetic ciphers. Created in the 15th century (1466/67), it was the peak of cryptography at that time. Its inventor was Leon Battista Alberti, an illegitimate son of an Italian nobleman.
- The Alberti Cipher – Computer Science – Trinity College
The Alberti Cipher is a type of polyalphabetic cipher. A polyalphabetic cipher is similar to a Substitution, cipher. In some cases the multiple alphabets are just rotations of the existing the existing alphabet.
- Alberti Wheel Cipher – Decoder, Encoder, Solver, Translator – dCode
Encryption uses a disk with two alphabets. By rotating a disk, it shifts an alphabet to the next letter. To encrypt, the disk is set in one position, the initial shift (which can be zero) corresponds to the number of letters shifted at the beginning.