Generating encoded useful data flow involves producing encoded version of useful data key using asymmetrical encoding and entering in useful data stream header block

摘要

The method involves generating a useful data key for a useful data encoding algorithm; encoding useful data using the key and algorithm to produce an encoded section of a useful data block (14); processing part of the useful data stream (10) to derive information identifying the useful data stream; combining the information with the useful data key to produce a base value; encoding the base value using one of two different keys using asymmetrical encoding, whereby the keys are the public and private keys for the asymmetrical encoding, to produce the encoded version of the useful data key; and entering the value in the header block (12) of the useful data stream. An Independent claim is also included for an arrangement for generating an encoded useful data flow.