Digital rights management system, devices, and methods for binding content to an intelligent storage device
View Patent ↗The present invention relates to digital rights management (DRM) for content that may be downloaded and bound to a storage device. The storage device may be an intelligent storage device, such as a disk drive, or network attached storage. In addition, the storage device is capable of performing cryptographic operations and providing a root of trust. In one embodiment, the DRM employs a binding key, a content key, and an access key. The binding key binds the content to a specific storage and is based on a key that is concealed on the storage. However, the binding key is not stored on the storage with the content. The content key is a key that has been assigned to the content, for example, by a trusted third party. The access key is determined based on a cryptographic combination of the content key and the binding key. In one embodiment, the content is encrypted based on the access key and stored in encrypted form in the storage device.
1. A storage device configured to generate a binding key for binding data stored in the storage device, said storage device comprising:
a storage medium comprising a user area and a non-user area; and
a controller comprising a cryptographic module providing a secured memory separate from the storage medium, wherein the controller is configured to:
generate a unique identifier based on defect data associated with the storage medium, the unique identifier being uniquely associated with the storage medium;
store the unique identifier in the non-user area of the storage medium;
determine a first cryptographic key stored in the secured memory of the cryptographic module;
generate a binding key that binds content to the storage device based at least in part on the unique identifier and the first cryptographic key;
provide the binding key to a remote download server over a secure communication channel; and
receive content from the download server encrypted based in part on the binding key.
2. The storage device of claim 1 , wherein the secured memory comprises a one-time-programmable, non-volatile memory.
3. The storage device of claim 1 , wherein the controller is further configured to digitally sign the unique identifier based on information provided by a hardware root of trust of the cryptographic module.
4. The storage device of claim 1 , wherein the controller is configured to generate the binding key as an ephemeral key.
5. The storage device of claim 1 , wherein the controller is further configured to prevent storage of the binding key in the user area of the storage medium.
6. A digital rights management system, said system comprising:
a content key server configured to provide a first cryptographic key for encrypting content;
a storage device comprising a storage medium and a controller configured to generate a binding key based on defect data associated with the storage medium and the first cryptographic key;
a download server configured to:
provide encrypted content to the storage device;
receive the binding key from the storage device;
receive the first cryptographic key from the content key server; and
encrypt the content based on at least the first cryptographic key and the binding key; and
a media player configured to receive the binding key, the first cryptographic key, and the encrypted content from the storage device, and decrypt the encrypted content based on at least the first cryptographic key and the binding key.
7. The system of claim 6 , wherein the media player and the storage device are configured to perform mutual authentication with each other.
8. The system of claim 6 , wherein the media player is configured to generate a decryption key based on at least the first cryptographic key and the binding key.
9. The system of claim 6 , wherein the storage device is configured as a network attached storage.
10. The system of claim 6 , wherein the storage device is configured to receive a private key and a public key in a secure manufacturing environment.
11. A method of determining a key that binds data to a storage device, wherein said storage device comprises a controller, a cryptographic module with a memory, and a storage medium, said method comprising:
generating a unique identifier based on defect data associated with the storage device, the unique identifier being uniquely associated with a storage medium of the storage device;
store the unique identifier in a non-user area of the storage medium;
determining, by the cryptographic module, a first cryptographic key that is concealed in the storage device;
generating, by the cryptographic module, a binding key that binds content to the storage device based at least in part on the unique identifier and the concealed first cryptographic key; and
transmitting the binding key to a server that provides the data to the storage device.
12. The method of claim 11 , further comprising determining the defect data at least in part by identifying a set of defects present on the storage medium.
13. The method of claim 11 , further comprising determining the defect data at least in part by identifying a defect log on the storage medium that was generated when the storage device was manufactured.
14. The method of claim 11 , wherein generating the binding key comprises generating the binding key based on information in a defect log.
15. The method of claim 11 , further comprising digitally signing the unique identifier based on information from a hardware root of trust provided by the storage device.
16. The method of claim 11 , further comprising concealing the first cryptographic key in a secured memory accessible by the cryptographic module.
17. The method of claim 11 , wherein generating the binding key comprises:
digitally signing the unique identifier based on information from a hardware root of trust provided by the storage device;
accessing the concealed first cryptographic key; and
determining the binding key based on at least the digitally signed unique identifier and the concealed first cryptographic key.