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Secure method of storing encrypted data on a personal digital recorder

A security unit and key technology, applied in digital recording/reproduction, electrical digital data processing, digital transmission system, etc.

Inactive Publication Date: 2010-05-12
NAGRAVISION SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0023] So there are unresolved issues when we store an event without rights at the moment of storage, or when the decryption conditions change between the moment of storage and the moment the event is manipulated by the user

Method used

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  • Secure method of storing encrypted data on a personal digital recorder
  • Secure method of storing encrypted data on a personal digital recorder
  • Secure method of storing encrypted data on a personal digital recorder

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0037] figure 1 The decoder (STB) shown in receives input data in encrypted form. These data are stored in the memory unit HD, notably, these data contain the considered event EV, the control message ECM and the entitlement message EMM.

[0038] According to the invention, during such a storage operation, the security unit SC receives control messages but does not retransmit them to the subscriber unit. On the contrary, the security unit SC encrypts the system key with the key S1, and this set of encrypted system keys SK is stored in the storage unit.

[0039] This key S1 can be a key for this decoder STB, a key for a group of decoders, or a single key for all decoders.

[0040] During reading, a specific mechanism is implemented in the security unit. In fact, it is not possible to replace existing keys with those contained in the set SK. In this case, the normal function of the decoder will be altered.

[0041]The keys contained in the group formed by the encrypted syste...

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PUM

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Abstract

The invention relates to a method of storing an event encrypted by control words (CW) on a decoder (STB). The inventive method guarantees access to the aforementioned event at all times, even if certain system keys have changed for security reasons. For this purpose, the invention relates to a method of storing an event encrypted by control words (CW) in a receiving and decryption unit which is connected to a security unit (SC), said control words (CW) and the necessary rights being contained in control messages (ECM, EMM) encrypted by system keys (TK, RK). The invention is characterised in that it consists in: storing the encrypted event and the control messages (ECM) on the storage unit, and also storing the system keys (SK), which are encrypted by a pre-defined local key that is storedin the security unit (SC), on said storage unit.

Description

technical field [0001] The present application relates to the field of receiver / decoders for conditional access services, in particular to receivers with storage units such as hard disks. Background technique [0002] Technological evolutions in the field of disk (hard disk) storage capacity and speed have made it possible to store broadcast video content so that it can be accessed offline by users. [0003] Such receivers are known under the brand Replay or And provide tens of hours of digital transmission storage capacity. These receivers are not always integrated in the receiver / decoder of the conditional access service; in particular, the content is stored on disc without special protection, which makes it impossible to redistribute it later for commercial purposes The royalty associated with the content is collected in case the disc is reproduced for the purpose of . [0004] In contrast, in digital pay television systems, the digital stream to the receiver is enc...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L9/00H04N5/913H04N7/16G06F21/62G06F21/60H04L9/10H04N1/00H04N5/00
CPCH04N7/163H04N2005/91364H04N5/913H04N21/4623H04N21/4181G11B20/10H04K1/00
Inventor 克里尼·利伯翰帕特里克·伯索莱特马柯·萨瑟利
Owner NAGRAVISION SA