Although it was originally described as "bullet proof," the encryption code devised to prevent the copying of high-definition DVD's using Toshiba's HD DVD system may have been broken. Reports appearing on several tech websites Thursday said that a hacker calling himself Muslix64 posted information on how to crack the Advanced Access Content System codes. A video that he posted on YouTube describes his technique. In it, he shows how he decrypted such films as Van Helsing and Full Metal Jacket and promised more information on January 2.