Vigenère Ciphers

Overview

The Vigenere Cipher Applet shown here on this web page is capable of encrypting and decrypting a message using the Vigenere algorithm as well as breaking or finding the key for a message encrypted using that algorithm.

The only restriction this applet has is that only letters may be used for the plaintext message, the ciphertext, and the key. Using any other characters such as punctuation and numbers will cause the applet to function improperly. Spaces or uppercase letters may be used. The applet will strip the message of any spaces and convert uppercase letters to lowercase letters before encrypting, decrypting, or breaking the message.

Encrypting a message

To encrypt a message:

1) Make sure that the plaintext message contains only letters and spaces -- no punctuation, numbers, or other characters.

2) Enter the message into the “PlainText:” text field.

3) Choose a key consisting of only letters -- no punctuation, numbers, or other characters.

4) Enter the key into the “Key:” text area.

5) Click on the “Encrypt” button to encrypt the message. The encrypted message will appear in the “CipherText:” text field.

For more information about encrypting a plaintext message, see the section called “Encryption & Decryption Explained.”

Decrypting a message

To decrypt a message:

1) Make sure that the ciphertext message contains only letters and spaces -- no punctuation, numbers, or other characters.

2) Enter the message into the “CipherText:” text field.

3) Make sure the key contains only letters and spaces -- no punctuation, numbers, or other characters.

4) Enter the key into the “Key:” text area.

5) Click on the “Decrypt” button to decrypt the message. The decrypted message will appear in the “PlainText:” text field.

For more information about decrypting a plaintext message, see the section called “Encryption & Decryption Explained.”

this link will show you more about vigenere ciphers http://islab.oregonstate.edu/koc/ece575/02Project/Mun+Lee/VigenereCipher.html