Patent ID: 8265275

Claim:
A computer-implemented method for use in a media device of protected content in which an authenticated data value is cryptographically checked, said method being performed by said media device and comprising the steps of: calculating a subset of a media key block on recordable media of protected content to be decrypted by said device, wherein said content was previously downloaded from a content provider and recorded on said media; reading an authenticated data value, wherein said data value is a media identifier for said media that attests the protected content came from a valid content provider server; identifying a media key precursor based on the calculated subset, wherein said media key precursor is a device key that was previously assigned to said device; using the media key precursor and said data value to decrypt an entry in a binding table on said media in order to produce an output media key, wherein said table was previously downloaded with said content and encrypted by said provider of said content; processing the output media key to cryptographically check said data value; and wherein said output media key will be decrypted if said data value is correct, which thereby allows said content to be accessed by said device.