Patent ID: 8498412
Filing Date: 2013-07-30
Classification: H04L,H04N

Abstract:
1. A method of providing an encrypted data stream, including obtaining a first data stream with a first stream of key messages, the first data stream comprising encrypted data, partitioned into sections corresponding to key periods, each of a plurality of the key periods being associated with a respective value of a key, wherein each section corresponding to a key period associated with a value of the key includes at least one encrypted data unit decryptable using that associated key value, obtaining a pre-encrypted replacement data stream section and an associated at least one replacement key message stream section, the at least one replacement key message stream section including a key message carrying key information for obtaining key values for the replacement data stream section and at least one encrypted data unit in a section of the first stream corresponding to a certain key period, forming an encrypted output data stream and an associated stream of key messages, the forming including: providing as output the encrypted output data stream in synchrony with the associated stream of key messages.