Patent ID: 7760877
Filing Date: 2010-07-20
Classification: G06F,G11B,H04N

Abstract:
1. A method for protecting access to content recorded on a media recording disk (DVD), the method comprising: providing a disk security chip on the DVD, the disk security chip managing access to the content of the DVD; providing a corresponding player security chip in a DVD player which is operative to play the DVD, the player security chip managing use of a data stream received from the DVD, the disk security chip being in wireless communication with the player security chip; providing the disk security chip with a disk key; the player security chip sending a random number R to the disk security chip, the random number R being different each time the DVD is played; the disk security chip sending the player security chip an encrypted concatenation of a hash function of R, called h(R), and the content key, encrypted with the disk key; the player security chip decrypting the concatenation, and computing h(R) and comparing with the h(R) sent by the disk security chip; the player security chip verifying R to be correct, thereby certifying that the disk chip really knows the player key; the player security chip obtaining the content key from the concatenation; and the player security chip using the content key to decrypt control words that are located within entitlement control messages (ECMs) in the DVD.