Controlled-access method and system for transmitting scrambled digital data in a data exchange network
First Claim
1. Method for transmission of digital data with access control to at least one terminal (4) connected to a data exchange network (2), characterised in that it comprises three steps:
- a first scrambling step consisting in;
scrambling digital data to be transmitted using a control word CW, generating a digital sequence S for each terminal calculated as a function of a first random data ALEA1 and of data distinctive of the terminal in the network, calculating at least one specific digital key K for the terminal (4) as a function of the digital sequence S and the control word CW, transmitting the corresponding specific digital key K to the terminal (4), a second broadcasting step consisting in;
transmitting scrambled digital data and the random digital data ALEA1 to the terminal (4), and a third descrambling step consisting in;
reconstituting the digital sequence S using the random data ALEA 1 and the address of the terminal in the network (2), decrypting the control word CW starting from the sequence S and the specific digital key K, descrambling the transmitted digital data.
2 Assignments
0 Petitions
Accused Products
Abstract
This invention relates to a method for transmission of digital data with access control to at least one terminal connected to a data exchange network (2), characterised in that it consists in:
scrambling data to be transmitted using a control word CW,
generating a digital sequence S for the terminal (4) calculated as a function of a first random data ALEA1 and data distinctive to the terminal in the network,
calculating at least one specific digital key K for the terminal (4) as a function of the digital sequence S and the control word CW,
transmitting the corresponding specific digital key K to the terminal (4).
-
Citations
37 Claims
-
1. Method for transmission of digital data with access control to at least one terminal (4) connected to a data exchange network (2), characterised in that it comprises three steps:
-
a first scrambling step consisting in;
scrambling digital data to be transmitted using a control word CW, generating a digital sequence S for each terminal calculated as a function of a first random data ALEA1 and of data distinctive of the terminal in the network, calculating at least one specific digital key K for the terminal (4) as a function of the digital sequence S and the control word CW, transmitting the corresponding specific digital key K to the terminal (4), a second broadcasting step consisting in;
transmitting scrambled digital data and the random digital data ALEA1 to the terminal (4), and a third descrambling step consisting in;
reconstituting the digital sequence S using the random data ALEA 1 and the address of the terminal in the network (2), decrypting the control word CW starting from the sequence S and the specific digital key K, descrambling the transmitted digital data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
-
-
20. Transmission system with access control of digital data scrambled by a control word CW to at least one terminal (4) connected to a data exchange network (2) comprising:
-
a reservation gateway (14), a platform (16) designed to scramble data to be transmitted, a server (6) designed to broadcast scrambled data, system characterised in that the reservation gateway (14) comprises;
means of generating a digital sequence S as a function of a random data ALEA1 and data distinctive of the terminal in the network (2), means of calculating a specific digital key K for the terminal (4), as a function of the digital sequence S and the control word CW. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29)
-
-
30. Reception device for scrambled digital data, characterised in that it comprises:
-
means of analysing all received datagrams, and if a datagram possesses the MultiCast address and the port corresponding to the chosen service, then means of eliminating the header specific to access control, means of descrambling the useful content, means of reinjecting the descrambled useful content onto the IP stack through a port dedicated to processing and display of the received program.
-
-
31. Method for changing the control word for access to scrambled data, characterised in that it comprises the following steps:
-
break down the subscription period into a series of crypto-periods CPi, each corresponding to the life of a control word (CWi), assign an even value to a crypto-period CPi and an odd value to the next crypto-period CPi+1, or an odd value to a crypto-period CPi and an even value to the next crypto-period CPi+1, generate at least one even control word and at least one odd control word for each crypto-period CPi, transmit a data throughput containing the address of the terminal (4) to the terminal (4), and a random data ALEA1 to change control word parity, transmit a change control word indicator to the terminal (4), such that this terminal (4) uses the even control word if the value assigned to the crypto-period is even, and the odd control word if the value assigned to the crypto-period is odd. - View Dependent Claims (32, 33, 34, 35, 36, 37)
-
Specification