Parental control codes on DVDs are designed to stop children watching movies their parents do not approve of. But some discs don鈥檛 have them. So Samsung in Korea has devised a DVD player to put parents firmly back in control (US 2004/49647).
The machine reads the electronic contents list at the start of every DVD and uses it to generate a signature code unique to that disc. The parent then enters a 鈥渘o play鈥� command against that code and locks it with a password. When the machine is asked to play a disc with a no-play code, it refuses unless the password is entered.
