How to use:
This program will accept a Vigenère cipher's ciphertext (encrypted text) and the key length (how many letters in key). Then using the English letter frequency, chi-squared test, and scoring algorithms, the program outputs the calculated key and plaintext (decrypted text).
- Visit cryptii.com to encrypt a message using Vigenère cipher
- a. In the text box to the left, enter the text you would like to encrypt
- Make sure there are no spaces
- The longer the text, the more accurate the results
- Example: ifyoutellthetruthyoudonothavetorememberanything
- b. In the box in the middle, click where it says "Enigma machine" and switch it to "Vigenère cipher"
- c. In the box in the middle, under the "Key" field, change the key to any English word
- The shorter the key, the more accurate the results
- Example: forever
- d. The box to the right is where the encrypted text (or ciphertext) is
- Example: ntpspxvqzklzxizhycjyutbfxcemjhfvzqvrpvvvrpyvzrb
- Copy and paste the encrypted text into the "Ciphertext" field below
- You can try: ntpspxvqzklzxizhycjyutbfxcemjhfvzqvrpvvvrpyvzrb
- Copy and paste the amount of letters in the key in the "Key word length" field below
- For the key "forever" it has 7 letters, so you can enter: 7
- Click the "Calculate Key" button below to calculate the key and decrypted text (plaintext)
