EP0179612B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Cryptographic system for direct broadcast satellite network
Assignee: Arris Technology Inc
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Filing: 1985-10-16
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Granted: 1991-08-07
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Expires: 2005-10-16
Abstract
No abstract record available.
Inventors
- 👤 Donald Horne
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 10:22
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/167; H04N7/1675; H04B; H04B7/00; H04B7/14; H04B7/15; H04B7/185; H04B7/18523; H04H; H04H20/00; H04H20/28; H04H60/00; H04H60/09; H04H60/14; H04H60/23; H04L; H04L9/00; H04L9/08; H04L9/0816; H04L9/0819; H04L9/0822; H04L9/083; H04L9/0891; H04H2201/00; H04H2201/70; H04L2209/00; H04L2209/56; H04L2209/60; H04L2209/601
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
168 words
A system for sending encrypted information from a transmission node for distribution to a plurality of receiver nodes each having an individual address number, the sending system comprising: means (14) for generating a common key for use in encrypting information to be sent; a first encryption stage (12) for receiving information in clear to be sent and responsive to said common key to encrypt said information with the aid of said common key so as to provide encrypted information for sending to all receiver nodes; means (18) storing the address numbers of the receiver nodes; means (20) storing a master encryption key; a second encryption stage (22) for encrypting a selected address number using said master encryption key to provide an individual receiver key for the receiver node having the selected address number; a third encryption stage (16) for encrypting said common key with the aid of said individual receiver key to provide an encrypted common key for sending to the receiver node having said selected address number.
Claim 2
Dependent Claim
60 words
A sending system as claimed in Claim 1 comprising a real time controller operable to control the selection of address numbers and the operation of said second encryption stage (22) such that, at each encryption of said common key by said third encryption stage, the relevant individual receiver key is generated in real time by said second encryption stage (22).
Claim 3
Dependent Claim
25 words
A sending system as claimed in Claim 1 or 2 in which said second encryption stage (22) operates according to the Data Encryption Standard algorithm.
Claim 4
Dependent Claim
25 words
A sending system as claimed in Claim 1, 2 or 3 in which said third encryption stage (16) operates according to a block cypher algorithm.
Claim 5
Dependent Claim
26 words
A sending system as claimed in Claim 1, 2, 3 or 4 in which said first encryption stage (12) operates according to a stream cypher algorithm.
Claim 6
Dependent Claim
69 words
A sending system according to any preceding claim, comprising means for selecting the address numbers of said plurality of receiver nodes in a sequence for encryption by said second encryption stage (22); and means for assembling a data stream (Fig. 4) for distribution to said receiver nodes which includes said encrypted common keys and respective address information identifying the receiver nodes for which each encrypted common key is intended.
Claim 7
Dependent Claim
44 words
A sending system as claimed in Claim 6 in which said means for assembling said data stream is adapted to provide addressed packets of data each comprising the address number of a receiver node and the encrypted common key pertaining to that address number.
Claim 8
Dependent Claim
45 words
A sending system as claimed in Claim 7 in which said data stream is incorporated within a television signal format having video signal portions and horizontal blanking intervals (HBI), said data stream being inserted into said horizontal blanking intervals to form a composite television signal.
Claim 9
Dependent Claim
21 words
A sending system as claimed in Claim 8 in which said encrypted information is inserted into said horizontal blanking intervals (HBI).
Claim 10
Dependent Claim
23 words
A sending system as claimed in Claim 8 or 9 in which said information in clear comprises audio accompanying a television picture transmission.
Claim 11
Dependent Claim
26 words
A sending system as claimed in any preceding claim in which said common key generating means (14) is operable to change said common key from time-to-time.
Claim 12
Dependent Claim
100 words
A receiver for use as a receiver node with the sending system of Claim 1, comprising: means (28) storing an individual receiver key pertaining to the address number of the receiver node; a first decryption stage (26) responsive to reception of an encrypted common key pertaining to the receiver node to decrypt same with the aid of the stored receiver key so as to recover said common key, and a second decryption stage (24) responsive to the reception of said encrypted information to decrypt same with the aid of said recovered common key and thereby recover said information in clear.
Claim 13
Dependent Claim
30 words
A receiver as claimed in Claim 12 for use with the sending system of Claim 4 in which said first decryption stage (26) operates according to a block cypher algorithm.
Claim 14
Dependent Claim
32 words
A receiver as claimed in Claim 12 or 13 for use with the sending system of Claim 4 in which said second decryption stage (24) operates according to a stream cypher algorithm.
Claim 15
Dependent Claim
55 words
A receiver as claimed in Claim 12, 13 or 14 for use with a sending system of Claim 6, further comprising means (32) storing address information pertaining to the receiver node for use in identifying an encrypted common key pertaining to said receiver node to enable decryption of same by said first decryption stage (26).
Claim 16
Dependent Claim
24 words
A receiver as claimed in Claim 15 in which said means (32) for storing address information stores the address number of the receiver node.
Claim 17
Dependent Claim
35 words
A receiver as claimed in Claim 15 or 16 for use with a sending system of Claim 8, comprising means for extracting the data stream from horizontal blanking intervals of a received composite television signal.
Claim 18
Dependent Claim
48 words
A subscribers' network of receiver nodes for receiving encrypted information and encrypted common keys sent by the sending system of Claim 1 in which each node is allotted a different address number and each node comprises a receiver as claimed in any one of Claims 12 to 17.
Claim 19
Dependent Claim
30 words
An information distribution network comprising a sending system as claimed in any one of Claims 1 to 11 and a subscribers' network of receiver nodes as claimed in Claim 18.
Claim 20
Independent Claim
204 words
A method of sending information from a transmitter node (Fig. 1) to a plurality of receiver nodes (Fig. 2) in which the information is distributed in encrypted form from the transmitter node to the receiver nodes and in which each receiver node has an individual address number allocated thereto, comprising the steps of: encrypting (12) information in clear with the aid of a common key and distributing the encrypted information from the transmitter node; encrypting (22) the address number of each receiver node entitled to have access to the information with a master key to provide a receiver key individual to the receiver node; encrypting (16) said common key with the aid of each receiver key to provide a respective encrypted common key and distributing the encrypted common keys for the receiver nodes entitled to have access to said information; storing (28) at each of said receiver nodes a receiver key individual thereto; decrypting (26) at each entitled receiver node the encrypted common key pertaining thereto with the aid of the stored receiver key to obtain said common key, and decrypting (24) the encrypted information received at each entitled receiver node with the aid of said common key to obtain the information in clear.
Claim 21
Dependent Claim
54 words
A method as claimed in Claim 20 in which the encryption (16) of the common key to obtain each encrypted common key is done with a block cypher algorithm, and the decryption (26) at a receiver node of the encrypted common key to obtain the common key is done with a block cypher algorithm.
Claim 22
Dependent Claim
56 words
A method as claimed in Claim 20 or 21 in which the encryption (12) of the information in clear to obtain the encrypted information is done with a stream cypher algorithm and the decryption (24) at a receiver node of the encrypted information to obtain the information in clear is done with a stream cypher algorithm.
Claim 23
Dependent Claim
35 words
A method as claimed in Claim 20, 21 or 22 in which the encryption (22) of each receiver node address number to obtain the individual receiver key is done with the Data Encription Standard algorithm.
Claim 24
Independent Claim
57 words
A method as claimed in any one of Claims 20 to 23 in which the encrypted common keys are assembled together with associated receiver node address information into a data stream (Fig. 4) for distribution, and each receiver node stores its address information and uses it to identify the encrypted common key pertaining to that receiver node.
Claim 25
Dependent Claim
56 words
A method as claimed in Claim 24 in which the data stream (Fig. 4) distributed to the receiver nodes comprises addressed packets of data each comprising the address number of a receiver node and the encrypted common key pertaining to that address number, and the address information stored by each receiver node is its address number.
Claim 26
Dependent Claim
40 words
A method as claimed in Claim 24 or 25 in which the data stream is incorporated within a television signal format having video signal portions and horizontal blanking intervals (HBI), the data stream being inserted into the horizontal blanking intervals.
Claim 27
Dependent Claim
20 words
A method as claimed in Claim 26 in which the encrypted information is inserted into the horizontal blanking intervals (HBI).
Claim 28
Dependent Claim
20 words
A method as claimed in Claim 27 in which said information in clear comprises audio accompanying a television picture signal.
Claim 29
Dependent Claim
28 words
An information distribution network as claimed in Claim 19 in which the distribution from the sending system to the receiver nodes is effected by direct broadcast by satellite.
Claim 30
Independent Claim
24 words
A method as claimed in any one of Claims 20 to 28 in which the information distribution is done by direct broadcasting by satellite.
References Cited (Backward Citations)
No citation records indexed.
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