The companies that sell this stuff are, at best, bunkum peddlers and, at worst, out and out fraudsters. Their wares simply can't work - not without changing the laws of physics, maths and information science.Link
DRMs are often designed by ambitious, well-funded consortia, with top-notch engineers from every corner of the industry. They spend millions. They take years. They are defeated in days, for pennies, by hobbyists. It's inevitable, because every time you give someone a locked item, you have to give them the key to unlock it too.
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.