Vigenère & Autokey Cipher Tool

An advanced polyalphabetic cipher tool with multiple modes and fine-grained control for powerful text encryption and decryption.

About The Vigenère & Autokey Cipher Tool

The Vigenère cipher is a classic method of encrypting alphabetic text by using a series of interwoven Caesar ciphers based on the letters of a keyword. This tool enhances this classic cipher by also including the **Autokey cipher**, a variant where the key is extended with the plaintext itself, making it significantly more secure against cryptanalysis.

Key Features:

  • Dual Cipher Modes: Choose between the standard **Vigenère cipher** and the more secure **Autokey cipher**.
  • Encrypt & Decrypt: Easily switch between encrypting your plaintext and decrypting a ciphertext.
  • Character Handling: Decide whether to keep non-alphabetic characters (spaces, numbers, symbols) in the output or remove them for a clean ciphertext.
  • Case Control: Choose to preserve the original letter case, or force the entire output to be uppercase or lowercase.
  • Real-time Transformation: The output updates instantly as you type or change any option.

How to Use:

  1. Enter the text you want to transform in the "Input Text" box.
  2. Provide a keyword in the "Keyword" field. Only letters are used.
  3. Select "Encrypt" to encode or "Decrypt" to decode.
  4. Choose your preferred "Cipher Type" (Vigenère or Autokey).
  5. Set your preferences for "Non-Alphabetic Handling" and "Output Case".
  6. The transformed message will instantly appear in the "Output Text" box.