Strange. I just started reading a 2-year-old book, Windows7 for Dummies 8 books-in-One and in the "Internet" section there is a discussion about this.
So it's not really a secret, although most of us have never heard of them.
Maybe we’ll all have to be using cryptographic tools in our web surfing.
I can see how the anarchists, Arabs and Chinese are using it, for unsavory activities.