Encrypt messages using the classic Vigenère cipher algorithm
The Vigenère cipher is a secure method of encrypting text that was considered unbreakable for centuries. To encrypt:
For maximum security, use a key that is as long as your message and share it securely with your recipient.
The Vigenère cipher was developed in the 16th century by Blaise de Vigenère and was known as "le chiffre indéchiffrable" (the indecipherable cipher) for 300 years until Charles Babbage broke it in the 19th century.
This cipher uses a keyword to shift letters in the plaintext. Each letter in the keyword indicates how many places to shift the corresponding letter in the plaintext (with A=0, B=1, etc.). The keyword is repeated to match the length of the plaintext.
Unlike simple substitution ciphers, the Vigenère cipher uses multiple substitution alphabets, making it much more secure against frequency analysis attacks.