ROT 13, the basic form of obfuscation. Seen in many textbooks on many a programming language on the subject of array operations and the most simplest encryption in the world. ROT13 simply rotates a byte value that represents a character 13 points in one direction to encrypt data, and 13 points back to decrypt it. It uses no passwords, security devices, dongles, or anything else for that matter. ROT13 is seen at times in cases where some blogs or web forums have content about movie endings and in such cases those who have not seen the ending might see the information in ROT13 and not want to decrypt the message until later. ROT13 can also be used to keep packet sniffers and data parsers in a network from finding information, however as protection of data goes this would be very weak encryption and would only "fool" eavesdropping measures that are not programmed for it. Programming for it would take very little time. As far as real protection of data is concerned, this is not real encryption.

Using ROT13 on a Blackbird-using website is easy. You need only right-click on the applet to pull up the applet's menu, and select the option that says "Encrypt Text For ROT13"

This will bring up a control panel for encrypting text with ROT13. It's very simple to use and requires no password. Simply enter the plaintext in the top text area, and then click the "Generate Encryption Entry" button at right. The "encrypted" data will be in the lower text area and you can copy it and paste it into the HTML of a web page or enter it into a blog or forum post.

In the HTML page, be it the raw source of if entered in the form of a blog or forum - one that does not filter out HTML - the encrypted data will look like this:

And when in the web page, whenever that page is loaded the applet will decrypt it: