Vigenère Cipher

What Is a Vigenère Cipher?

The Vigenère Cipher tool encrypts and decrypts text using a polyalphabetic substitution where each letter is shifted by a different amount determined by a repeated keyword. Invented in the 16th century, it was famously considered unbreakable for over 300 years. This free online tool is useful for Vigenere cipher, Vigenère cipher online, Vigenere encrypt decrypt. Common use cases include classical cryptography, puzzles, history, and cryptography education. It is designed for quick browser-based hashing, encoding, decoding, encryption testing, checksum comparison, identifier generation, and cryptography education. For production security, follow the algorithm's current standards, key-management requirements, and application-specific security guidance.