I think Keurig's and Lexmark's definition of success might be different than yours though. They don't need the DRM to be unbreakable. They just need to protec

I think Keurig's and Lexmark's definition of success might be different than yours though. They don't need the DRM to be unbreakable. They just need to protect their market enough that the benefits (to them) of the DRM exceed the costs. In the case of digital media, any weakness in the DRM means game over, because file sharing is so easy. But when talking about physical goods like printer ink and coffee capsules, it's a battle at the margins. They just need to discourage enough competition that their business stays profitable.