The Vigenère cipher is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It is a form of polyalphabetic substitution.
The cipher is easy to understand and implement, but it resisted all attempts to break it for three centuries, which earned it the description le chiffre indéchiffrable (French for 'the indecipherable cipher'). Many people have tried to implement encryption schemes that are essentially Vigenère ciphers.[3] In 1863, Friedrich Kasiski was the first to publish a general method of deciphering Vigenère ciphers.