Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L63/00—Network architectures or network communication protocols for network security
  • H04L63/04—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
  • G06F21/10—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]
  • G06F21/101—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM] by binding digital rights to specific entities
  • G06F21/1014—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM] by binding digital rights to specific entities to tokens
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
  • G06F21/10—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]
  • G06F21/109—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM] by using specially-adapted hardware at the client
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
  • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
  • G11B20/00485—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier
  • G11B20/00492—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier wherein content or user data is encrypted
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
  • G11B20/0021—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier
  • G11B20/00485—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier
  • G11B20/00543—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving encryption or decryption of contents recorded on or reproduced from a record carrier characterised by a specific kind of data which is encrypted and recorded on and/or reproduced from the record carrier wherein external data is encrypted, e.g. for secure communication with an external device or for encrypting content on a separate record carrier
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
  • G11B20/00086—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy
  • G11B20/00884—Circuits for prevention of unauthorised reproduction or copying, e.g. piracy involving a watermark, i.e. a barely perceptible transformation of the original data which can nevertheless be recognised by an algorithm
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L63/00—Network architectures or network communication protocols for network security
  • H04L63/08—Network architectures or network communication protocols for network security for authentication of entities
  • H04L63/0823—Network architectures or network communication protocols for network security for authentication of entities using certificates
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L63/00—Network architectures or network communication protocols for network security
  • H04L63/08—Network architectures or network communication protocols for network security for authentication of entities
  • H04L63/0853—Network architectures or network communication protocols for network security for authentication of entities using an additional device, e.g. smartcard, SIM or a different communication terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L2463/00—Additional details relating to network architectures or network communication protocols for network security covered by H04L63/00
  • H04L2463/101—Additional details relating to network architectures or network communication protocols for network security covered by H04L63/00 applying security measures for digital rights management

Definitions

• Device for restoring digital content secure electronic entity, system comprising these elements and method for rendering digital content
• the invention relates to a device for restoring a digital content, a secure electronic entity and a system comprising these elements, and a method for restoring a digital content.
• conditional access systems are used.
• Such a system of common use most often consists in encrypting the digital content by means of an encryption system which makes the content accessible only to persons holding a cryptographic key, for example stored in a secure electronic entity, such as a microcircuit card.
• digital watermark visible is detected in the content, only to restore the content if a certificate is present on a microcircuit card paired with the rendering device.
• the microcircuit card is thus used as a license authority authorizing the return of the content bearing the watermark.
• the invention proposes a device for restoring a digital content, characterized by means for receiving an identifier of the digital content from a secure electronic entity, means for extracting a digital watermark from the content and means. controlling the rendering of the content based on a comparison based on the extracted watermark and the identifier.
• the restitution of the content may be conditioned by the correspondence between the watermark it contains and the identifier stored in the secure electronic entity.
• the means for receiving the identifier of the digital content comprise, for example, means for establishing secure communication with the secure electronic entity, which makes it possible to avoid making the identifier accessible to malicious people.
• the means for establishing secure communication include, for example, means for decrypting the identifier of the digital content: the encryption makes it possible to provide security that is relatively simple to implement and effective.
• the means for establishing a secure communication can use a session key for the encryption of the secure communication.
• the rendering device may comprise means for decrypting an encrypted version of the digital content received from the secure electronic entity: thus preventing easy access to the digital content during its transmission, for example after a first decryption, of the electronic entity to the rendering device.
• the means for decrypting said encrypted version may in practice use a session key.
• the device may comprise means for exchanging with the secure electronic entity the session key in encrypted form, and possibly means for generating the session key.
• the means for exchanging the session key can be configured to be activated each time the device is powered up.
• the rendering device may also comprise means for transmitting the encrypted digital content to the secure electronic entity, for example as it receives it from a remote server for decryption within the secure electronic entity.
• an integrated circuit comprises the means for receiving the identifier, the means for extracting the watermark and the control means.
• control means of the reproduction of the content are for example able to control the restitution of the content in case of equality between two data respectively from the extracted watermark and the identifier. Said data can then be respectively the extracted watermark and the identifier.
• the watermark is usually an imperceptible watermark, so that attackers can not access it.
• the secure electronic entity is for example a removable portable entity, such as a microcircuit card or a USB protocol information medium, generally referred to as "USB key”.
• L ⁇ digital content is a perceptible content, for example an audio content, in which case sound reproduction means can be controlled by said control means and the integrated circuit can comprise a digital analog converter, or a video content, in which case the device of rendering may comprise a screen and means for displaying the content on the screen controlled by said control means.
• the device may further comprise means for receiving data representative of the digital content of a remote server; the representative data can then be decrypted by means of a key stored in the secure electronic entity.
• the content can also be received through a communication network, for example a broadcast network over airwaves or cable. Alternatively, it could be discharged directly from an information carrier such as an optical disk or a semiconductor memory. Means can also be provided for receiving the identifier of a remote server and means for transmitting the identifier to the secure electronic entity.
• the identifier is for example received encrypted and able to be decrypted by means of a key, possibly temporary, stored in the secure electronic entity.
• the rendering device is a mobile phone. The rendering device can then receive the digital content and / or the identifier through the associated mobile telephone network.
• the secure electronic entity may be a microcircuit card for managing access rights to a mobile telephone telecommunications network.
• the rendering device may be, for example, a personal computer or a digital television decoder.
• the identifier is identical for all copies of the same content.
• the invention also proposes a secure electronic entity capable of cooperating with a device for restoring a digital content, characterized by means for transmitting an identifier of the digital content to the rendering device.
• Means for transmitting the identifier of the digital content may include means for establishing secure communication with the rendering device, which may incorporate means for encrypting the identifier of the digital content.
• the secure electronic entity may also have characteristics corresponding to those mentioned above about the rendering device.
• the electronic entity may comprise means for decrypting an encrypted version of the digital content received from the rendering device, possibly by means of a cryptographic key, possibly temporary and / or shared with a remote server.
• the invention further provides a system comprising a device and an electronic entity as discussed above.
• the invention finally proposes a method of restoring a digital content, characterized by the following steps:
• the reception of the identifier of the digital content can implement a secure communication with the secure electronic entity and / or the secure communication implements an encryption by means of a session key.
• the secure communication implementing an encryption by means of a session key
• FIG. 1 shows a retrieval device according to the teachings of the invention
• FIG. 2 represents a logic diagram illustrating the operation of the apparatus of FIG. 1 and interactions with other elements
• FIG. 3 represents a logic diagram of the same type as that of FIG. 2 illustrating other parts of the operation of the apparatus of FIG. 1
• FIG. 4 represents a possible embodiment for the exchange of a session key.
• FIG. 1 represents the main elements of a device for restoring a digital content, here of audio type.
• the rendering device is a mobile phone, here cell.
• teachings of the invention naturally apply to other types of device, such as for example portable digital players or personal computers configured to constitute a playback device.
• the invention applies particularly interestingly to the case of digital audio content, as described here, but can also be used for other types of content, namely in particular video-type content and content of software type.
• the rendering device of FIG. 1 comprises a CPU 300 (or CPU for "Central Processing Unit") implemented by a microprocessor.
• the central unit 300 is connected by means of a data bus 305 to the other electronic circuits which form the rendering device, namely in particular a memory 310, a microcircuit card reader 350, a communication circuit 340 and a circuit
• the memory 310 allows the storage of programs (including a content restoration management program 311 and a decompression program 314) performed by the central unit 300.
• the memory 310 also stores data such as a compressed and encrypted digital content M 'referenced 110 and a key data K3. These data are stored and exchanged with the other circuits of the device according to terms explained below.
• the memory 310 also comprises a first buffer memory area 312 (referred to in the buffer figures I) and a second buffer memory area 313 (referred to in the ⁇ buffer figures).
• the memory 310 has been shown in FIG. 1 in the form of a single block, it will naturally be possible to physically provide different memories, of possibly different types, for storing the elements that have just been mentioned.
• a rewritable memory for example of the EEPROM type
• a random access memory in which access will be faster
• the example of the reproduction device envisaged here also comprises, as already indicated, a communication circuit 340 which allows the exchange of data with other electronic devices, for example by means of electromagnetic telecommunications.
• the rendering device is a cellular phone and the data exchanged by means of the communication circuit 340 can also be related to communications, including voice, provided by the cell phone.
• the microcircuit card reader 350 linked to the central unit 300 via the bus 305, carries a microcircuit card 320 in operation and thus enables the exchange of data between the central unit 300 and the microcircuit card 320.
• the microcircuit card 320 comprises data storage means, such as key data K2, K3, K4, identifier data Id and the compressed and encrypted digital content M '(or at least a part thereof). ), all shown in simplified form by blocks on the microcircuit card 320.
• the microcircuit card 320 may also, but not necessarily, contain data relating to communication rights on a cellular network, in particular for the voice communications mentioned above.
• the audio reproduction circuit 330 comprises a securing circuit 331 linked to the other circuits by means of the bus 305.
• the security circuit 331 is able to supply digital data, in the manner described below, a digital converter - analog 333 which controls sound reproduction means 332, for example of the speaker or earphone type.
• Encryption is for example a symmetric key encryption (such as that using the DES algorithm). Alternatively, it could be an asymmetric key encryption, as allowed for example the RSA algorithm.
• the compression used is, for example, an MPEG-4 compression
• AAFC alternatively, it could be MPEG-4 HE-ACC compression or 3GPP Extended AMR WB (AMR-WB +) or other compression.
• the compressed and encrypted digital content M ' stored in the form of a file, has been supplied to the rendering apparatus by a content server, for example by means of the communication circuit 340.
• the file M could be retrieved from the content server (or another content server) via a personal computer, and then transferred to the rendering device (here I cell phone), for example by means of a cable or wireless data exchange means.
• the file M 'could be stored directly in the microcircuit card (and it would then not be necessary to transmit it to the card during the step E126 described below).
• the digital content corresponding to the file M ' also carries (once decrypted and decompressed) an imperceptible digital watermark linked to an identifier Id of the content and which will be used as indicated below.
• FIGS. 2 and 3 represent the main steps implemented in the various elements of the rendering device when the user requests the reproduction of the content represented by the file M ', namely in practice listening to the musical piece formed by this file .
• FIG. 2 represents the steps implemented within the microcircuit card (steps E101 to E110), within the rendering apparatus itself (in particular by means of the program 311 generally referred to as "Playet”, referenced steps E120 to E136) and at a licensing center
• the process begins with an authentication of the microcircuit card holder at the licensing center.
• Such a procedure authentication with generation of a temporary key (K5 in the following) is described for example in the patent application FR 2 837 336.
• the licensing center generates during a step E140 a random value A.
• Random value means a value that can not be expected from the outside, sometimes referred to as pseudo-random value.
• the random value A is transmitted to the microcircuit card 320 via the reproduction device (and in particular the communication circuit 340) during a step E120.
• the microcircuit card 320 calculates during a step E101 and using the cryptographic key K2 that it holds, an authentication word MA and a temporary key K5 used in the following for exchanges between the licensing center and the microcircuit card 320.
• the authentication word MA and the temporary key K5 are for example calculated as proposed by the aforementioned patent application FR 2 837 336.
• the microcircuit card 320 then transmits the authentication word MA during a step E102, by means of the communication circuit 340 (step E121), to the licensing center which can thus verify during a step E141 that the microcircuit card 320, which could determine the authentication word MA from the random value A, was indeed holder of the cryptographic key K2.
• the licensing center thus proceeds to the authentication of the microcircuit card 320.
• the rendering apparatus may request at step E122 an electronic license of the song M at the licensing center, for example by transmitting a code identifying the piece M to the center.
• the licensing center then checks (step E142) the rights on the chip M associated with the previously authenticated microcircuit card.
• step E144 If no license purchase right of the song M has been registered with the licensing center, the process is terminated (step E144) so that the restitution of the song M (although stored in the memory 310 as a compressed and encrypted file M 1 ) does not occur.
• the licensing center issues at a step E146 the electronic license consisting of an identifier Id associated with the piece M and a key K1, and encrypted by means of the temporary key K5 obtained during the authentication, as well as rights of use on the digital content purchased and granted to the holder of the the microcircuit card.
• the central unit 300 controls the storage thereof in the microcircuit card 320 (step E125).
• the microcircuit card 320 thus stores in step E103, after decryption by means of the key K5, the electronic license Id, K1.
• step E126 The execution of the program 311 by the central unit 300 then generates (step E126) a request for decryption of the compressed and encrypted content M 'in the direction of the microcircuit card 320.
• the microcircuit card 320 proceeds during a step E104 to decrypt the content M 'by means of the key K1 previously received as explained above. To do this, the central unit 300 transmits to the microcircuit card 320 the content M 'in encrypted and compressed form.
• the microcircuit card 320 temporarily stores the compressed and encrypted content M '(as indicated by a dashed line in FIG. 1) and decrypts the encrypted content M' into a compressed (and therefore decrypted) content M.
• the compressed digital content M is not directly re-transmitted by the microcircuit card 320, but encrypted by means of a session key K3 as described below.
• the central unit 300 and the microcircuit card 320 exchange a session key K3, for example according to the method described further with reference to Figure 4.
• This exchange may also take place beforehand, for example, each time the power supply device is turned on.
• the microcircuit card then proceeds, during a step E108, to the encryption of the compressed digital content M by means of the session key K3 previously exchanged and thus generates a new encrypted and compressed version M "of the digital content, which is transmitted during a step E110 to the central unit 300.
• Described above is decryption of the entire content M as a single step.
• the rendering apparatus On receiving the new version M "(step E130), the rendering apparatus decrypts it by means of the session key K3 in order to find the compressed digital content M (step E132).
• the compressed digital content M is then stored in the first buffer zone 312 during a step E134. Furthermore, the decompression program 314 decompresses (in a step E136) the contents of the first buffer area 312 towards the second buffer area 313.
• the decryption and decompression of the digital content can be done in parts and in parallel.
• the first buffer zone 312 where it can then be decompressed by means of the program 314, which stores the decompression result in the second zone buffer 313.
• the digital content is always exchanged between the microcircuit card 320 and the reproduction device in encrypted form or, in other words, by means of secure links between the microcircuit card and the rendering apparatus.
• FIG. 3 represents the main steps of the operation of the part of the reproduction apparatus dedicated to reproducing the digital content from the data stored in the second buffer memory 313 (that is to say from the decrypted data and uncompressed); in the example of FIG. 1, this part of the apparatus dedicated to reproduction is the audio reproduction circuit 330.
• the method of reproduction stricto sensu begins with the exchange of a session key K4 between the microcircuit card (step E202) and the security circuit 331 (step E220). This session key exchange can be performed according to the method proposed above for session key K3 and described below with reference to FIG. 4.
• the exchange of the session key K4 can take place as soon as the playback device is powered up.
• the microcircuit card proceeds during a step E204 to the encryption of the identifier Id (part of the electronic license received from the issuing center as described above), by means of the session key K4, in order to obtain the identifier in encrypted form Id '.
• the encrypted identifier Id is then transmitted from the microcircuit card 320 (step E206) to the security circuit 331 (step E222) through the reader 350 and the bus 305 which form, thanks to the session key K4, a connection secure to transmit the identifier.
• the security circuit 331 can then proceed to decrypt the encrypted identifier Id 'by means of the session key K4 in order to find the identifier Id of the digital content (here of the piece) M during a step E224.
• the security circuit 331 also reads the decrypted and decompressed content in the second buffer zone 313 and searches in this content for the presence of a digital watermark during a step E226.
• step E227 for checking the presence of a watermark returns directly to the step E232 described below. These are, for example, cases where part of the digital content can be returned without the need for authorization.
• step E227 returns to a step E228 of comparison between the detected watermark and the ID Id of the piece.
• This comparison may for example constitute the verification of the equality between the detected watermark and the identifier.
• the digital watermark is imperceptible and robust so that it is not possible for an attacker outside (who does not know the extraction method used or the secret key that it uses) to have access to the identifier Id.
• step E228 returns to the step E232 to which the security device 331 transmits the previously read data in the second buffer zone 313 to the digital converter 333 which causes the return of content by sound reproduction means 332.
• the processing described in FIG. 3 is preferably applied to only a part of the digital content and resumes after step E232 in step E226 of detecting a watermark in the content stored in second buffer zone 313.
• the periodic presence of the digital watermark in the content is preferably provided, which makes it possible periodically to verify the conformity of the content and the license rights (represented by the identifier Id) and to terminate the restitution as soon as non-compliance is noted.
• the microcircuit card holds a cryptographic key K s , associated for example with the card itself or with a set of cards intended to cooperate with the apparatus, while the reproduction apparatus holds a cryptographic key of its own.
• KHW as well as its certificate K 'which is equal to the key KHW encrypted by means of the key K 3 .
• the algorithm for encryption in the method of FIG. 4 uses the AES algorithm in CBC mode.
• the rendering apparatus proceeds in a step E400 drawing a random number (or pseudo-random) A 1 . 11 then proceeds to encrypt the number A 'by means of the key KHW to obtain a number A "during a step E402.
• the rendering apparatus then transmits the values A "and K 'to the microcircuit card during a step E406
• the microcircuit card receives these values during a step E408.
• step E410 It proceeds during a step E410 to decrypt the encrypted key K 'by means of the key K s in order to determine the cryptographic key KHW, then to decrypt the value A "by means of the key KHW during a step E412 to find the random number A '
• the microcircuit card then proceeds during a step E414 to draw a random number (or pseudo-random) K3, which will be used as session key in the following but whose rendering apparatus is not yet known (step E414).
• the microcircuit card then calculates during a step E416 the product of an exclusive or (XOR) between the session key K3 and the random number A ', in order to obtain a value K3 1 (step E416), which is then encrypted by means of the key K H w to obtain a number K3 "(step E418).
• XOR exclusive or
• This number K3 " can be sent during a step E420 to the rendering apparatus, where it is received (step E422) .
• the rendering apparatus which knows by hypothesis the key KHW, can decipher the number K3 "to find the number K3" (step E424), which makes it possible to find, by means of an operation of or exclusive (XOR) between K3 1 and A 1 , the session key K3 (step E426).
• the two entities are thus aware of the K3 session key by means of exchanges that give no indication of this to malicious third parties.
• the session key used can be derived from the random number K3 obtained in step E414 by virtue of a function shared by the microcircuit card and the rendering device. .

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• Engineering & Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Signal Processing (AREA)
• General Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Computer Networks & Wireless Communication (AREA)
• Computing Systems (AREA)
• Software Systems (AREA)
• Theoretical Computer Science (AREA)
• Multimedia (AREA)
• Technology Law (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Storage Device Security (AREA)

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• 2006
  • 2006-03-29 FR FR0651089A patent/FR2899409B1/fr not_active Expired - Lifetime
• 2007
  • 2007-03-27 EP EP07731207A patent/EP2005703A1/de not_active Withdrawn
  • 2007-03-27 US US12/294,992 patent/US20100241863A1/en not_active Abandoned
  • 2007-03-27 WO PCT/FR2007/000525 patent/WO2007110510A1/fr not_active Ceased

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