ROT13 – Unleash the unknown words!

I just encountered an amazing stuff while reading the Ryan Russell and Stace Cunningham’s Hack proofing your network. On page 146, he gives an introduction to cryptography and how it was first used in Egypt 4000 years ago! Then he brings up the ROT13 subject and shows how the algorithm works, simply by rotating the letters to the right by thirteen and gives and example that reads as follows:

V GUVAX JVAQBJF…

that’s equivalent to “I THINK WINDOWS”. The amazing stuff I was talking about was those ROT13-encoded texts already on the net. Try the following links and you’ll see for yourself.

• What does “NT” in “Windows 2000: Based on NT Technology” stand for?
• ILOVEYOU

and much much more. 🙂

Here’s a simple function (written in C#) that decodes the ROT13 text:

foreach (char ch in input)
{
    int code = ch;
    if (char.IsLetter(ch))
        code = ch + (((int)char.ToUpper(ch) < 'A' + 13) ? 13 : -13);

    Trace.Write((char)code);
}

where input is the ROT-13 encoded text.