Patent ID: 8578157

Claim:
A device comprising: one or more processors; and memory coupled to the one or more processor, the memory comprising instructions executable by the one or more processors to implement a digital rights management (DRM) component configured to: generate a request for a private key; the request comprising a credential specific to the device; receive the private key of an authorized device group, the receipt of the private key of the authorized device group indicating the device is an authorized member of a group of devices permitted to access content items protected by a common public key associated with the authorized device group; and for each content item of a plurality of content items that are encrypted with different content keys: decrypt an encrypted content key from the encrypted content item with the private key of the authorized device group, the encrypted content key having been distributed with the encrypted content item; and decrypt content from the encrypted content item with the decrypted content key; responsive to a determination to exclude the device from the authorized device group: receive a block of cryptographic data, the block being broadcast to the device, the block structured in such a way that prevents the device from calculating an update private key common only to devices within the authorized device group, wherein the block is structured in such a way based on credentials of the device and on a set of calculations the device performs to arrive at private keys common to devices in the authorized device group; and calculate the new private key that excludes the device from the authorized device group.