Digital rights management (DRM) encryption and data-protection for content on device without interactive authentication
AssigneeMicrosoft Corporation
InventorsM. Jay Parks, Marcus Peinado, Jonas Fredrik Helin, Clifford P. Strom
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Abstract
A device renders content on a medium by obtaining a table from the medium, obtaining a device key (DK) of the device and an index value of such (DK), indexing into an entry of the table based on the obtained index value, selecting an encrypted secret from the indexed-into entry, applying the obtained device key (DK) to the selected encrypted secret to expose the secret, and applying the exposed secret to render the content.
Claims24
A method performed in combination with a host computer and a device having a device key (DK) with a pre-selected index value, the device for receiving a storage medium or having the storage medium, the storage medium having stored thereon digital content protected according to a secret and a table with a plurality of entries therein, each entry including the secret encrypted according to a key decryptable by the device key (DK) of one of a plurality of devices and an index value, the medium including a first ID thereon identifying such medium and comprising a serial number permanently associated with the medium, and the table including a second ID of the medium stored therein, wherein the table is tied to the medium by the second ID, the method for the device to render the content on the medium and comprising:
- receiving a request to render the content on the medium;
- obtaining the table from the medium;
- obtaining the first ID of the medium therefrom;
- obtaining the second ID of the medium as stored in the table;
- comparing the first ID and the second ID to each other;
- and
- if the first ID and the second ID match, proceeding by:
- obtaining the device key (DK) of the device and the index value of such (DK);
- indexing into an entry of the table based on the obtained index value;
- selecting the encrypted secret from the indexed-into entry;
- applying the obtained device key (DK) to the selected encrypted secret to expose the secret;
- and
- applying the exposed secret to render the corresponding content.
A method performed in combination with a host computer and a plurality of devices each having a device key (DK) with a pre-selected index value, each device for receiving a storage medium or having the storage medium, the storage medium including an ID thereof thereon, and having stored thereon digital content protected according to a secret and a table with a plurality of entries therein, each entry including the secret encrypted according to a key decryptable by the device key (DK) of one of a plurality of devices and an index value, the method for the host computer to provide the medium with the table and comprising:
- obtaining the table from a cache;
- obtaining the ID of the medium therefrom, the ID of the medium comprising a serial number permanently associated with the medium;
- appending the ID of the medium to the table;
- employing a device key (DK) and the index value thereof to find the corresponding entry in the obtained table and expose the secret of such table, by:
- obtaining the table from the medium;
- obtaining the device key (DK) of the host computer and the index value of such (DK);
- indexing into an entry of the table based on the obtained index value;
- selecting the encrypted secret from the indexed-into entry;
- and
- applying the obtained device key (DK) to the selected encrypted secret to expose the secret;
- tying the table to the medium by the ID of the medium and the exposed secret;
- and
- copying the tied table to the medium.
A method performed in combination with a host computer and a storage medium including a first ID thereon identifying such medium and comprising a serial number permanently associated with the medium, and having stored thereon a table with a plurality of entries therein, each entry including a secret encrypted according to key decryptable by a device key (DK) of one of a plurality of devices and an index value, at least one of the secrets being a current secret of the table, the table including a second ID of the medium stored therein, wherein the table is tied to the medium by the ID, the method for storing digital content on the medium according to the current secret of the table and comprising:
- obtaining the first ID from the medium;
- obtaining the second ID of the medium as stored in the table;
- comparing the first ID and the second ID to each other;
- and
- if the first ID and the second ID match, proceeding by:
- obtaining the current secret from the table, by:
- obtaining the table from the medium;
- obtaining a device key (DK) of the host computer and the index value of such (DK);
- indexing into an entry of the table based on the obtained index value;
- selecting the encrypted secret from the indexed-into entry;
- and
- applying the obtained device key (DK) to the selected encrypted secret to expose the current secret;
- applying the obtained current secret and the obtained ID to a pre-determined function to produce a final secret;
- protecting the content to be stored on the medium according to the final secret, thereby tying the content to the medium by the ID thereof;
- and
- copying the protected content to the medium.
Dependencies are inferred from the claim text.