Vigenère Cipher

Encrypt and decrypt text using the Vigenère cipher with a keyword. A polyalphabetic substitution cipher that shifts each letter based on the corresponding keyword character.

How to Use Vigenère Cipher

The Vigenère Cipher tool encrypts and decrypts text using a keyword-based polyalphabetic substitution cipher. Unlike simple Caesar ciphers that use a single shift, the Vigenère cipher uses a keyword where each letter determines the shift for the corresponding plaintext character. Enter your text, provide a keyword (letters only), select encrypt or decrypt mode, and get instant results. This tool is great for learning about classical cryptography, solving puzzles, or encoding messages. All processing happens in your browser.

Step-by-Step Instructions

  1. Enter the text you want to encrypt or decrypt
  2. Enter a keyword (letters only)
  3. Select Encrypt or Decrypt mode
  4. Click the button and copy your result

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