TETHERED DEVICE SYSTEMS AND METHODS

• US 20090037732A1
• Filed: 07/23/2008
• Published: 02/05/2009
• Est. Priority Date: 07/23/2007
• Status: Active Grant

• Current Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Original Assignee: Intertrust Technologies Corporation (Fidelio Acquisition Co LLC)
• Inventors: Boeuf, Julien, Ellison, Gary F., Boccon-Gibod, Gilles, Maher, David P.
• Granted Patent: US 8,850,195 B2
• Time in Patent Office: Days
• US Class Current: 713/168
• CPC Class Codes: G06F 21/1012 to domains
• CPC Class Codes: G06F 21/1013 to locations
• CPC Class Codes: G06F 21/1015 to users
• CPC Class Codes: G06F 21/1073 Conversion
• CPC Class Codes: G06Q 20/3829 involving key management
• CPC Class Codes: G06Q 50/184 Intellectual property management
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838

Abstract

Systems and methods are described for applying digital rights management techniques to tethered devices. In one embodiment, a host device is operable to translate a relatively sophisticated license into a simpler format for use on a relatively low-capability device. In another embodiment, a method of using extended SCSI commands to communicate over a USB connection is provided.

Claims

1. A method of exporting a license from a host device to a target device, the license for use in governing access to or other use of a piece of electronic content, the method comprising:

using a pairing key to encrypt a first cryptographic key, the first cryptographic key being configured for decrypting the piece of electronic content;

executing a control program, included in the license, to obtain one or more conditions relating to granting access to the piece of electronic content;

creating a data structure that includes the encrypted first cryptographic key and an indication of the one or more conditions;

digitally signing at least part of the data structure using the pairing key; and

sending the data structure to the target device.

2. The method of claim 1, further comprising:

making a determination as to whether the one or more conditions make reference to at least one node; and

conditionally generating one or more link validity statement records based on a result of the determination, wherein each of the one or more link validity statement records provides an indication of whether at least one node is reachable from at least another node.

3. The method of claim 2, in which at least a first link validity statement record includes an indication of a condition that must be satisfied in order for the first link validity statement record to be valid.

4. A method comprising:

identifying a simple validity statement associated with an encrypted piece of electronic content, the simple validity statement having been derived from a license comprising one or more control programs;

using a pairing key to verify a digital signature associated with at least part of the simple validity statement;

evaluating one or more conditions expressed in the simple validity statement to determine if the simple validity statement is valid;

if the simple validity statement is determined to be valid, using the pairing key to decrypt a content decryption key; and

decrypting the encrypted piece of electronic content using the content decryption key.

5. The method of claim 4, in which the step of evaluating one or more conditions comprises determining whether a current time value is before a first predefined time value.

6. The method of claim 5, in which the step of evaluating one or more conditions comprises determining whether the current time value is after a second predefined time value.

7. The method of claim 4, in which the step of evaluating one or more conditions comprises determining whether a first state variable is set to a predefined value.

8. The method of claim 5, in which the step of evaluating one or more conditions comprises determining whether a first state variable is set to a predefined value.

9. The method of claim 4, in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.

10. The method of claim 5, in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.

11. The method of claim 8, in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.

12. A method of managing a tethered device'"'"'s membership in a first domain, the method comprising:

obtaining a link object logically connecting a first node representing the tethered device to a second node representing the domain;

sending the tethered device a communication operable to set a state object in the tethered device to a predefined value;

using the link object to create a link validity statement (LVS) logically connecting the first node to the second node, the LVS containing a condition that indicates that the LVS is only valid if the state object is set to the predefined value; and

sending the LVS to the tethered device.

13. The method of claim 12, further comprising obtaining an agent program, the agent program being operable to perform said sending the tethered device a communication.

14. The method of claim 12, further comprising sending a communication operable to delete the state object from the tethered device.

15. The method of claim 12, further comprising:

sending a simple validity statement (SVS) to the tethered device, the SVS being associated with a piece of electronic content and expressing one or more conditions that must be satisfied in order to make authorized use of the piece of electronic content, at least one of the one or more conditions requiring possession by the tethered device of a valid LVS logically connecting the first node to the second node.

16. The method of claim 15, in which at least one of the one or more conditions requires that a time at which access to the piece of electronic content is granted be before a predefined time.

17. The method of claim 15, in which the step of sending the SVS to the tethered device is conditioned upon a determination that the tethered device to be capable of metering usage of the piece of electronic content.

18. The method of claim 15, in which the step of sending the SVS to the tethered device is conditioned upon a determination that the tethered device does not have an output having a predefined characteristic.

19. The method of claim 15, further comprising:

sending the piece of electronic content to the tethered device.

20. A method of communicating between a first device and a second device, the method comprising:

obtaining one or more Universal Serial Bus (USB) descriptors from the second device;

parsing the one or more USB descriptors for an indication that the second device supports a predefined extended Small Computer System Interface (SCSI) communication protocol;

upon determining that the second device supports the predefined extended SCSI communication protocol, identifying one or more extended SCSI commands recognized by the second device;

sending a first communication to the second device using one of said one or more extended SCSI commands, the first communication including a payload that comprises one of a plurality of predefined commands; and

receiving a second communication from the second device, the second communication comprising one of said one or more extended SCSI commands, the second communication further comprising a payload that comprises one of the plurality of predefined commands.

21. The method of claim 20, in which obtaining one or more USB descriptors from the second device includes obtaining a first USB descriptor from a first predefined location, and, if the first USB descriptor does not satisfy predefined criteria, obtaining a second USB descriptor from a second predefined location adjacent to the first predefined location.