RU2000119752A - SCRAMBING DEVICE FOR DIGITAL TRANSMISSION SYSTEM - Google Patents

Claims (16)

1. A scrambling device for a digital audio-visual information transmission system, comprising an input for receiving a constituted stream of transport packets from a physically separate multiplexer, a scrambling unit for scrambling a received transport stream in accordance with an arbitrary control word, and an output for transmitting a scrambled transport stream to a transmission medium for subsequent transmission made with the possibility of scrambling the stream of transport packets with a scrambling device tion, regardless of the operation of the multiplexer.  2. The scrambling device according to claim 1, wherein the scrambling unit is configured to scramble part or all of the payload of the selected packets of the transport packet stream.  3. The scrambling device according to claim 1 or 2, which further comprises means for inserting packets for introducing data of the transport packet into the transport stream.  4. The scrambling device according to claim 3, wherein the packet insertion means is adapted to introduce a data packet into the transport stream by detecting the presence of a zero packet and replacing such a packet with the packet to be inserted.  5. A scrambling device according to any one of the preceding paragraphs, which further comprises a packet filtering means for identifying and copying to memory part or all of a given transport packet.  6. The scrambling device according to any one of the preceding paragraphs, which further comprises means for removing packages to remove a given package or group of packages.  7. The scrambling device according to claim 6, in which the packet removal means is configured to remove the packet by replacing the identifier of this packet with the identifier of the zero packet.  8. The scrambling device according to any one of the preceding paragraphs, which further comprises a packet counting means for counting the number of packets with a predetermined PID value in a received transport stream data.  9. The scrambling device according to any one of the preceding paragraphs, which further comprises a remapping means for changing the value of the packet identifier assigned to some given packet or group of packets.  10. A scrambling system comprising a scrambling device according to any one of the preceding paragraphs, as well as a central control means for generating a control word transmitted to and received by the scrambling device for scrambling the transport stream.  11. The scrambling system according to claim 10, which further comprises one or more access control systems connected to the central control means and adapted to receive a control word transmitted by the central control means and transmit back to the central control means an encrypted message containing said control word.  12. The scrambling system according to claim 10 or 11, in which the central control means is configured to authenticate part or all of the data transmitted from the central control means to the scrambling device by generating a signature using some secret encryption key.  13. The scrambling system according to any one of paragraphs. 10 to 12, which contains several scrambling devices and associated central control means involved in the formation of a single transport stream.  14. The scrambling system according to any one of paragraphs. 10-13, in which a single or each scrambling device is configured to save the parameters of its working configuration and / or the current value of the control word.  15. Scrambling device, practically the same as described here with reference to the accompanying drawings and as shown in these drawings.  16. Scrambling system, practically the same as described here with reference to the accompanying drawings and as shown in these drawings.