| 摘要 |
A method and a system for generating a scrambled data stream is described, wherein the method comprises: providing a code book comprising code information for scrambling data in data stream comprising one or more service streams; generating a control word request associated with at least one crypto period in at least one of said service streams; in response to said control word request, generating on the basis of said code information at least one control word associated with said crypto period in said service stream; and, scrambling data associated with at least one of said service streams using said control word. |
