Vigenère Cipher
Vigenère Cipher Overview
Polyalphabetic substitution encryption
The Vigenère Cipher is a polyalphabetic substitution cipher, meaning it uses multiple Caesar Ciphers based on a keyword. For centuries, it was known as 'le chiffre indéchiffrable' (the indecipherable cipher). Unlike simple substitution, the same letter can be encrypted differently depending on its position. This makes it much stronger against frequency analysis. It's a great step up for anyone interested in serious historical cryptography.
How to Use Vigenère Cipher
- Enter your text in the input box.
- Enter a 'Keyword' (e.g., 'SECRET'). This key is required to decrypt.
- Select 'Encrypt' or 'Decrypt' mode.
- The tool processes the text using the keyword pattern.
- Copy the result.
Frequently Asked Questions
- Is it unbreakable?
- Not anymore. With modern computers, it can be broken, but it is significantly harder to crack than monoalphabetic ciphers.
- Does the keyword length matter?
- Yes. A longer keyword that matches the text length (One-Time Pad) is theoretically unbreakable, provided the key is random.
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