Bagpuss
Legend
Reminds me of the biggest problem of any DRM measurement that exists:
It's more a hassle to the customer than to someone using a pirated version. Sure, the pirates first have to crack your DRM, but in the end that will always be possible, since the protected material will eventually "leak out" unprotected to the users eyes, and shortly before that, it will be in unprotected digital form. (Until we have brainware encryption/decryption.)
Which is why DRM has been dropped by the music industry. They still go after pirates but they now don't penalise the paying customers and have made efforts to make their music accessible in a legal and affordable form through other sources. For example I'm currently listening to the entire content of Bat for Lashes new album free online legally, it is tempting me to go out and buy the CD.