EP0506435A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Independent external security module for a digitally upgradeable television signal decoder
Assignee: Scientific Atlanta LLC
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Filing: 1992-03-27
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Granted: —
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Expires: 2012-03-27
Abstract
Abstract A decoder for descrambling encoded satellite transmissions comprises an internal security module and a replaceable security module. The program signal is scrambled with a key (704) and then the key itself is twice-encrypted (710,715) and multiplexed (732) with the scrambled program signal. The decoder (706) performs a first key decryption using the second secret serial number (SSN₂) stored within the decoder (712). The partially decrypted key is then further decrypted by the replaceable security module (714) using the first secret serial number (SSN₁) stored within the replaceable security module (717). The decoder then descrambles (708) the program using the twice-decrypted key. The replaceable security module (714) can be replaced, allowing the security system to be upgraded or changed following a system breach. Either security module may become the active security module to finally decrypt the seed, selectable by a signal transmitted from the encoder (721). Also disclosed is a method for transmitting (1284) the encrypted keys and secret serial numbers to a plurality of broadcasters (1286) who may in turn multiplex this signal with their own program signals so that any given channel received by a subscriber (1289) contains the key and secret serial numbers. Additionally, the decoder (1306,1390) may be upgradeable to accept both analog and digital video signals without significant redundant circuitry.
Inventors
- 👤 Keith Gammie
- 👤 Robert K. Yoneda
- 👤 Arthur Woo
- 👤 Wayne c/o Scientific-Atlanta Inc. Sheldrick
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 16:47
CPC Classifications
H; H04; H04N; H04N21/00; H04N21/40; H04N21/43; H04N21/44; H04N21/4405; H04N21/45; H04N21/462; H04N21/4623; H04N7/00; H04N7/16; H04N7/162; H04N7/163; H04N7/167; H04N7/1675; H04N7/20; H04N21/41; H04N21/426; H04N5/00; H04N5/44; H04N5/46
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
223 words
A security system for transmission of a signal comprising: encoder means (701) for encoding said signal, said encoder means (701 ) comprising: signal scrambling means (703) for scrambling said signal and outputting a scrambled signal and key for descrambling said scrambled signal, first key encryptor means (710) coupled to said signal scrambling means (703), for selectively performing a first encryption on said key using a first confidential serial number and outputting an encrypted key, second key encryptor means (711) coupled to said scrambling means for selectively performing a second encryption on said key using a second confidential serial number and outputting an encrypted key, and decoder means (706) for receiving and descrambling said scrambled signal, said decoder means (706) comprising: first key decryptor means (719) for performing a first key decryption on said encrypted key using said first confidential serial number if said key was encrypted with said first confidential serial number, a replaceable security module (714), removably attached to said decoder means (706) and containing a second key decryptor means (718) for performing a second key decryption on said encrypted key using a second confidential serial number if said encrypted key was encrypted with said second confidential serial number, and signal descrambling means (708) coupled to said first and second key decryptor means for descrambling said scrambled signal using said decrypted key.
Claim 2
Dependent Claim
28 words
The security system of claim 1, wherein said encoder means (701) further comprises: key memory means (704) coupled to said signal scrambling means (703) for storing said key.
Claim 3
Dependent Claim
60 words
The security system of claim 1, wherein said encoder means (701) further comprises: a first confidential serial number database (711) coupled to said first key encryptor means (710), containing a list of first confidential serial numbers, and a second confidential serial number database (716) coupled to said second key encryptor means (711), containing a list of second confidential serial numbers.
Claim 4
Dependent Claim
133 words
A decoder for receiving and descrambling a signal which has been scrambled using a key which has been selectively encrypted, said decoder comprising: first key decryptor means (718) coupled to said decoder, for performing a first key decryption on said encrypted key using a first confidential serial number and outputting a decrypted key if said key was encrypted using said first confidential serial number, a replaceable security module (714), removably attached to said decoder and containing a second key decryptor means (719), for performing a second key decryption on said key using a second confidential serial number and outputting a decrypted key if said key was encrypted using said second confidential serial number, signal descrambling means (708) coupled to said second key decryptor means for descrambling said scrambled signal using said decrypted key.
Claim 5
Dependent Claim
33 words
The decoder of claim 1 or 4, further comprising: first and second key memory means (707, 720) coupled to said first and second key decryptor means (713, 718), for storing said decrypted key.
Claim 6
Dependent Claim
38 words
The decoder of claim 1 or 4, further comprising: first and second confidential serial number memory means (712, 717) coupled to said first and second key decryptor means (713, 718), for storing first and second confidential serial numbers.
Claim 7
Dependent Claim
16 words
The system or decoder of claim 1 or 4, wherein said signal is a television signal.
Claim 8
Dependent Claim
15 words
The decoder of claim 7, wherein said television signal is a B-MAC type television signal.
Claim 9
Dependent Claim
24 words
The decoder of claim 1 or 4 further comprising: telephone interface means (875) for transmitting and receiving data to and from a television provider.
Claim 10
Dependent Claim
24 words
The security system of claim 9, wherein subscriber input data is transmitted by the replaceable security module (714) via said telephone interface means (875).
Claim 11
Dependent Claim
51 words
The replaceable security module (714) of claim 1 or 4, wherein said first and second memory means further comprise: security means for allowing the contents of said first and second confidential serial number memory means (712, 717) to be read only by said first and second key decryptor means (713, 718).
Claim 12
Dependent Claim
75 words
The decoder of claim 1 or 4, further comprising: means for receiving (1306) a plurality of compressed digital signals with a plurality of addresses, each address corresponding to a particular digital signal; means for selecting (1392) a particular digital signal by identifying the particular address; means, coupled to the means for selecting, for decompressing (1393) the digital signal; and means for removably coupling (1397) connected between the means for receiving and the means for selecting.
Claim 13
Independent Claim
108 words
A method of decoding a signal comprising the steps of: receiving a scrambled signal and an encrypted key in a decoder (706), performing a first decryption of said encrypted key using a first confidential serial number to produce a decrypted key signal, if said key was encrypted with said first confidential serial number, performing a second decryption on said encrypted key in a replaceable security module (714) removably attached to said decoder using a second confidential serial number to produce a decrypted key, if said key was encrypted with said second confidential serial number, and descrambling said scrambled signal using said decrypted key to produce a descrambled signal.
Claim 14
Dependent Claim
22 words
The decoder or method of claim 1, 4 or 13, wherein said first confidential serial number is assigned to said decoder (706).
Claim 15
Dependent Claim
24 words
The decoder or method of claim 1, 4 or 13, wherein said second confidential serial number is assigned to said replaceable security module (714).
Claim 16
Dependent Claim
70 words
The method of claim 13, further comprising the steps of: providing subscriber information including said encrypted key and said first and second confidential serial numbers at a first source; providing a plurality of program signals at a plurality of second sources; transmitting the subscriber information to the second sources; combining the subscriber information with the program signals to produce a combined signal; and, transmitting the combined signal to said decoder.
Claim 17
Independent Claim
82 words
An apparatus for converting an analog reception system to accept both analog and digital signals comprising: means for receiving (1306) a plurality of compressed digital signals with a plurality of addresses, each address corresponding to a particular digital signal; means for selecting (1392) a particular digital signal by identifying the particular address; means, coupled to the means for selecting, for decompressing (1393) the digital signal; and, means for removably coupling (1397) connected between the means for receiving and the means for selecting.
Claim 18
Dependent Claim
22 words
The apparatus of claim 13 or 17 further comprising means for decrypting (1399) said television signal coupled to said means for decompressing.
Claim 19
Independent Claim
71 words
A method of communicating subscriber information to a broadcasters of program signals in a program environment comprises the steps of: providing the subscriber information at a first source; providing the plurality of program signals at a plurality of second sources; transmitting the subscriber information to the second sources; combining the subscriber information with the program signals to produce a combined signal; and, broadcasting the combined signal to at least one subscriber.
Claim 20
Dependent Claim
67 words
A decoder for decoding a key which has been either encrypted by a first confidential serial number, a second confidential serial number, or both, the decoder characterized by: means for actively switching (708), in response to a detected signal, between a first key decryptor means (719) within the decoder and a replaceable security module (714) removably attached to the decoder so as to effectively decrypt the key.
Claim 21
Dependent Claim
55 words
A decoder for decoding a key which has been either encrypted by a first confidential serial number, a second confidential serial number, or both, the decoder characterized by: means for actively switching (708), in response to a received signal, between first and second key decryptor means (714, 719) so as to effectively decrypt the key.
Claim 22
Dependent Claim
74 words
A composite data packet addressed to a single decoder or group of decoders comprising: a first data packet (9a) containing unencrypted data for addressing the individual or group of decoders; a second data packet (9c) containing unencrypted data for determining whether at least one of first and second key decryptor means (714, 719) in the decoder are to be enabled; and, a third data packet (9d) containing encrypted data for use by the decoder.
Claim 23
Dependent Claim
46 words
The composite data packet of claim 22 further comprising a fourth data packet (9b) containing unencrypted data for determining the order of decrypting the third data packet by the first and second key decryptor means (714, 719) if the third data packet had been twice encrypted.
Claim 24
Dependent Claim
30 words
The composite data packet of claim 22 further comprising: a decoder (706) for receiving the composite data packet, the decoder comprising the first and second key decryptor means (714, 719).
Claim 25
Dependent Claim
123 words
A method replacing a replaceable security module (714) into the system of claim 1 without compromising the security of the system, wherein the system is currently operating with the key encrypted by the first confidential serial number, the method comprising the steps of: encrypting a new key with a new first confidential serial number; encrypting the new key with the second confidential serial number, thus producing a twice encrypted key; transmitting the twice encrypted key to the first key decryptor means (719); decrypting the twice encrypted key by the first key decryptor means (719), thus producing a once decrypted key; decrypting the once decrypted key by the replaceable security module (714); and, encrypting the key with only the second confidential serial number thereafter.
References Cited (Backward Citations)
No citation records indexed.
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