Tethered device systems and methods
View Patent ↗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.
1. A method comprising:
identifying a simple validity statement associated with an encrypted piece of electronic content, the simple validity statement having been generated by a host device and derived from a license comprising one or more control programs;
using a pairing key generated by the host device 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,
wherein the pairing key is generated based on a pairing between the host device and a particular device.
2. The method of claim 1 , in which the step of evaluating one or more conditions comprises determining whether a current time value is before a first predefined time value.
3. The method of claim 2 , in which the step of evaluating one or more conditions comprises determining whether the current time value is after a second predefined time value.
4. The method of claim 1 , in which the step of evaluating one or more conditions comprises determining whether a first state variable is set to a predefined value.
5. The method of claim 2 , in which the step of evaluating one or more conditions comprises determining whether a first state variable is set to a predefined value.
6. The method of claim 1 , in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.
7. The method of claim 2 , in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.
8. The method of claim 5 , in which the step of evaluating one or more conditions comprises determining whether a first node is reachable.