What is vigener?

Vigenère was a French cryptographer who lived from 1523 to 1596. He is known for inventing the Vigenère cipher, which is a polyalphabetic substitution cipher that uses a series of different Caesar ciphers based on the letters of a keyword. This makes it much harder to crack than simple substitution ciphers. The Vigenère cipher was considered unbreakable for many centuries and was used for secret communication by many governments and militaries. However, in the 19th century, frequency analysis techniques were used to break the cipher, and now it is considered a fairly weak form of encryption. Despite this, the Vigenère cipher is still studied today as a historical example of cryptography.