Conditional access system using messages with multiple encryption keys
First Claim
1. A message for delivering access conditions to a service scrambled using a control word, said message containing:
- n items, each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn,wherein n is an integer greater than 1.
2 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to a conditional access system making it possible for a service provider to supply his services solely to users having acquired entitlements to these services.
The services supplied by a service provider consist of an item scrambled by control words. To keep these control words secret, they are supplied in messages (MEC) after having been encrypted with an encryption algorithm with key K.
According to the invention, one and the same message (MEC) contains the same control word (Cwi) encrypted several times, each encryption (E(Cwi)Kj) of the control word depending on a different encryption key (Kj).
The invention applies to any type of conditional access system, be this system either of "off-line" or "on-line" type.
19 Citations
35 Claims
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1. A message for delivering access conditions to a service scrambled using a control word, said message containing:
n items, each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn, wherein n is an integer greater than 1. - View Dependent Claims (2, 3, 4)
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5. A message for delivering access conditions to services delivered by p different service providers scrambled using a control word, said message containing:
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p first items, each for identifying one of said p service providers; and
, for each of said p service providers of rank k (k=1, 2, . . . , p);vk (vk =n, m, . . . , v, . . . , w) second items, each comprising said control word encrypted using different encryption keys Kk1, Kk2, . . . , Kkj, . . . , Kkvk ; wherein p and vk are integers greater than 1. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A method for descrambling a service scrambled using a control word, said method comprising the step of:
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supplying a message containing access conditions associated with a user and n-items, each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn, wherein n is an integer greater than 1. - View Dependent Claims (12)
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13. A method for descrambling services, delivered by p different service providers, scrambled using a control word, said method comprising the step of:
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supplying a message containing access conditions associated with a user together with p first items, each for identifying one of said p service providers;
said message further comprising, for each service provider of rank k (k=1, 2, . . . , p);vk (vk =n, m, . . . , v, . . . , w) second items, each comprising said control word encrypted using different encryption keys Kk1, Kk2, . . . , Kkj, . . . , Kkv; wherein p and vk are integers greater than 1. - View Dependent Claims (14, 15, 16)
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17. A smart card for providing a control word for descrambling a received scrambled service comprising:
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means for receiving a first message, said first message containing data corresponding to access conditions associated with a user and n items each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn, wherein n is an integer greater than 1; and means for validating said first message using a validation key Q; wherein said validation key Q is different from all said encryption keys. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A conditional access system for selectively supplying services to a user comprising:
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means for providing a service scrambled using a control word, entitlement data associated with said user'"'"'s entitlements and access conditions data associated with access conditions, said access conditions data containing n items each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn, wherein n is an integer greater than 1; a decoder for descrambling said scrambled service; a smart card for receiving said entitlement data and said access condition data and for providing said control word to said decoder, wherein said smart card comprises deciphering means for decrypting said encrypted control word, said deciphering means containing at least one of said encryption keys. - View Dependent Claims (25, 26)
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27. A conditional access system for selectively supplying services delivered by p different service providers to a user comprising:
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means for providing a service scrambled using a control word, entitlement data associated with said user'"'"'s entitlements and access condition data associated with access conditions; a decoder for descrambling said scrambled service; a smart card for receiving said entitlement data and said access condition data and for providing said control word to said decoder, wherein said access conditions data are conveyed to said smart card in a message containing p first items, each for identifying one of said p service providers; and
, for each of said p service providers of rank k (k=1, 2, . . . , p);vk (vk =n, m, . . . , v, . . . , w) second items, each comprising said control word encrypted using different encryption keys Kk1, Kk2, . . . , Kkj, . . . , Kkvk ; wherein p and vk are integers greater than 1; and wherein said smart card includes; means for receiving a first message, said first message containing data corresponding to access conditions associated with a user and n items each comprising said control word encrypted using n different encryption keys K1, K2, . . . , Kj, . . . , Kn, wherein n is an integer greater than 1; and means for validating said first message using a validation key Q; wherein said validation key Q is different from all said encryption keys. - View Dependent Claims (28, 29)
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30. An off-line information medium containing:
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data scrambled using a string of N control words Cw1, . . . , Cwi, . . . CwN, N being an integer greater than 1; and for each of said N control words Cwi; a string of additional data comprising said control word encrypted using different encryption keys K11, . . . , K1n, K21, . . . , K2m, Kk1, . . . , Kkv, Kp1, . . . Kpw. - View Dependent Claims (31, 32, 33, 34)
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35. A smart card for providing a control word for descrambling a received scrambled service delivered by one among p different service providers comprising:
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means for receiving a message, said message containing data corresponding to access conditions associated with a user and containing; p first items, each for identifying one of said p service providers; and
, for each of said p service providers of rank k (k=1, 2, . . . , p);vk (vk =n, m, . . . , v, . . . , w) second items, each comprising said control word encrypted using different encryption keys Kk1, Kk2, . . . , Kkj, . . . , Kkvk wherein p and vk are integers greater than 1; means for validating said message using a validation key Qk which is associated with said service provider delivering the scrambled service, wherein said validation key Qk is different from all said encryption keys.
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Specification