This applet encrypts and decrypts texts using a given key. One text is encrypted with a given key and you need to know this key to decrypt the text. The key is a string such as "heaven" or "potatoes"... You enter a key and your text and then you click the encrypt button. You can email your encrypted text to people who knows the key you have used, they can decrypt the text using the same applet, by clicking the decrypt button.