Patent ID: 8068516
Filing Date: 2011-11-29
Classification: H04J,H04L,H04N

Abstract:
1. A method for synchronizing cable modems and encrypting a data stream, the method comprising the stages of: generating, at a media access control (MAC) enabled entity, synchronization messages; evaluating, by a processing and multiplexing entity, delays between receptions of the synchronization messages and transmissions, towards a transmitter, of updated synchronization messages; updating, at the processing and multiplexing entity, the synchronization messages to provide updated synchronization messages, whereas said updating is responsive to the evaluated delays; receiving, at the processing and multiplexing entity, at least one data stream destined to at least one cable modem and receiving encryption key provision messages that comprise encryption keys generated by the MAC enabled entity, whereas each encryption key is associated with at least one cable modem; wherein each encryption key provision message further comprises a sequence number field that has a unique value for each encryption session, a validity field that indicates whether the encryption key is valid, a MAC address field that includes a MAC address of one or more cable modems that are associated with the encryption key, and a key remaining lifetime indicative of a remaining lifetime of the encryption key; sending, by the processing and multiplexing entity, a key acknowledgement message that comprises a validity field, a MAC address field and a status field; and encrypting, by the processing and multiplexing entity, the at least one data stream with the at least one encryption key associated with the at least one cable modem; wherein the encryption key and the synchronization messages are sent from the MAC enabled entity to the processing and multiplexing entity over a network; and wherein at least a portion of additional content is encrypted with the encryption key that is associated with the at least one cable modem.