CN101466020A - Decipher processing method for digital content format - Google Patents

Abstract

The invention discloses a decryption processing method of SDCF and relates to the technical field of digital copyright protection, aiming at solving the technical problem of SDCF decryption processing. The decryption processing method relates to the following platforms: a DRM agent of a set-top box, a DRM copyright releasing system and a middleware; wherein, the DRM agent comprises an RO management module, a key management module, a content decryption module, a monitoring control module with a playing-before control submodule, a player, a browser and the like. The decryption processing method comprises the following steps: 1) users select programs by a user interface and acquire a global unique program logo and the URL of the program contents; 2) according to the program logo, the playing-before control submodule locally searches the corresponding RO and checks the limits to rights; 3) according to the URL in a data packet for transmitting digital contents, the content decryption module acquires the corresponding RO, a decryption mode and a content key to finish the decryption. The decryption processing method has the characteristics that: the network load can be reduced; the operation is simple and convenient; and the technical requirements can be satisfied.

Description

A kind of decipher processing method of digital content format

Technical field

The present invention relates to digital copyright protection technology, particularly relate to the digital content protection technology in the operation.

Background technology

The digitized content service have the quality height, can mutual, customizable characteristics, can bring freer, more also abundant so more attractive consumption experience to the user, provide with operator to content simultaneously and bring bigger market and profit margin; But the profit of powerful demand, great number has also attracted a lot of piracy rings to attempt digitized content is carried out bootlegging and gets sudden huge profits.Digital copyright protecting arises at the historic moment; protect for the digital content of operation by necessary, feasible, rational technological means; provide lawful right with operator with maintenance content; the basic order that ensures digital market is to safeguard forward, positive excitation, with the health that guarantees digital content marketplace, lasting development.

Digital copyright protecting needs three fundamentals: the rights of using of this digital content that the content ciphertext after the encryption, the key that is used for this digital content of encryption and decryption and user order.The user orders also three relevant fundamentals of complete acquisition digital content by digital property right management (DRM) system, and correctly receive, handle related content by terminal, verify corresponding rights of using, can decipher the plaintext that restores digital content, and enjoy the service of customization.

In digitized content operation process, present content data packets is generally used DCF (DRM ContentFormat) form.DCF is a kind of DRM content data packets based on ISO constituent instruments form, wherein comprises protected media content and associated metadata.Media content can be video, audio frequency etc., and metadata is the data relevant with DRM.

In the applied environment that the digitized content of reality is runed; demand at the speed in system development cycle, cost and the information process, efficient; can utilize the knowability of operating environment and the coordinability between operation assembly and the terminal; set the content protecting form of the new simplification of a cover; utilize the stream media format of present standard, ripe treatment technology as far as possible; can develop stable ripe commercial system fast, and accelerate the processing speed of system, guarantee service quality.

At above-mentioned problems of the prior art, though proposed a kind of content format (Simplified DRM Content Format is called for short SDCF) of digital copyright management of simplification at present, can simplify digital content format greatly,, satisfy technical need to reduce network payload; But its corresponding decipher processing method is change not, has influenced the promotion and application of SDCF.

Summary of the invention

At the defective that exists in the above-mentioned prior art, technical problem to be solved by this invention provides and a kind ofly can reduce network payload, and is easy and simple to handle, satisfies the decipher processing method of digital property right management protection form (SDCF) of the simplification of technical need.

In order to solve the problems of the technologies described above, the invention provides the decipher processing method of a kind of SDCF, its establish and platform comprise rights issuer, the middleware of the DRM agency and the DRM of set-top box, wherein the DRM agency comprises RO administration module, key management module, content decryption module, supervision control module and player, browser etc., monitors to be provided with in the control module to broadcast preceding control submodule; It is characterized in that decipher processing method comprises the steps:

1) user selects program by user interface, obtains the URL (URL(uniform resource locator)) of the unique program identification ContentID of the overall situation and this programme content.

2) broadcast preceding control module according to the RO of ContentID, and check authority in the local search correspondence; If do not search the failure of corresponding RO or scope check, terminal is then to rights issuer application copyright; If successfully apply for RO, then carry out scope check; If can not or can not apply for corresponding RO through scope check, set-top box then can report an error and return; If can pass through scope check, and obtain URL, decryption mode and the content key of corresponding digital content, then enter step 3);

3) content decryption module obtains corresponding RO from broadcasting preceding control module, and obtains decryption mode and content key, thereby finish decryption work according to the URL in the packet that transmits digital content.

Further, the program in the described step 1) comprises VOD program request (ISMA data flow) program and live (TS data flow) program.

Further, what play in the described step 1) is programme televised live, should add the transmission rule control bit TSC (Transport Scrambling Control) of tagged keys state in packet.

Further, described transmission rule control bit is provided with two bit-identifies, respectively expression: program is not encrypted, program is normally encrypted, program is about to more new key, key new key more.

Further, program is general programs (promptly do not have encrypt program) in the described step 1), and player is in described step 2) in (before broadcasting in the control) control well after the authority, directly send to player; No longer pass through content decryption module.

Further, program is about to more new key in the described step 1), and then the RO administration module need be applied for new RO to the backstage, in order to decryption content behind the replacing key.

Further, program has been changed key in the described step 1), and then content decryption module uses decryption mode and decruption key in the new right objects to carry out data processing, and deletes old RO.

Further, program is normally encrypted in the described step 1), then the content decryption module normal process promptly obtains decryption mode and content key by control module before broadcasting from the RO of this program correspondence, and uses content key decrypts digital content under the algorithm of decryption mode.

Wherein, the program of considering request program has certain-length and the storage of the assigned address in media server, therefore this patent does not recommend request program to use the processing method of this complexity, and when system is not in a hurry (as point in mornings three) handover key, and in a period of time before the key switching instant, generally slightly be longer than length of a film, close program, promptly the user can not pass through electric program menu EPG (Electronic Program Guide) this program of program request.

Adopt the decipher processing method of the SDCF of the present invention's proposition, can satisfy the technical need of SDCF, make the content format of the digital copyright management of simplification in digitized content operation process, obtain promotion and application.The SDCF form need add any data at data packet head hardly, thereby simplified operation, remedy the limitation that DCF (DRM Content Format) form in OMA (Open MobileAlliance) agreement can not data streams simultaneously, enlarged the promotion and application scope of SDCF.

Description of drawings

Fig. 1 is the system construction drawing of embodiments of the invention DRM;

Fig. 2 is the DRM agency's of embodiments of the invention set-top box a structure chart;

Fig. 3 is the variation schematic diagram of embodiments of the invention key stage of replacement TSC;

Fig. 4 is the handling process schematic diagram of embodiments of the invention DRM Agent according to TSC sign position.

Embodiment

Below in conjunction with description of drawings embodiments of the invention are described in further detail, but present embodiment is not limited to the present invention, the decipher processing method of the SDCF data format that every employing is similar to the present invention all should be listed protection scope of the present invention in.

The present invention can be applied to following scene:

1) provides VOD order program service, be decrypted broadcast for the files in stream media of SDCF form;

2) provide real-time direct broadcast service, be decrypted broadcast for the streaming media data stream of SDCF form;

3) provide the time shifting broadcasting service, be decrypted broadcast for the segmentation files in stream media that satisfies the SDCF form;

4) provide other digital content services, be decrypted use for the corresponding digital content that satisfies the SDCF form.

Because in Network Transmission, the data of SDCF form utilize the source data packet address to differentiate the file purposes, replace the data head of DCF; For downloading to local digital content, only corresponding URL need be pointed to local respective stored space, just can obtain the processing in the Network Transmission that all fours introduces below.So a protected digit content, following several important indicator is arranged:

1) can be made terminal can identify protected digit content, and it is carried out corresponding decryption processing by the sign of terminal recognition.

2) can identify the authentication of protected digit content uniquely, make terminal obtain the mandate and the content corresponding key of this digital content by certain approach.

3) in order to seamlessly transit cipher key change, for data flow and segmental file, the general user mode that also needs certain sign position to come tagged keys.

Accordingly, operation system provides corresponding sign position in order to satisfy above-mentioned three indexs, and for the reduced data encapsulation, SDCF formulates the following rules:

1) owing to provides the server of digital content product to fix, so use the source address of packet to identify the protected digit content product whether corresponding file is ordered as the user.Obviously, in the system that can independently allocate, this scheme is easy to realize; At can not be fully autonomous mixing system or provide under the situation that the server of ciphertext may change; terminal should provide corresponding menu to the user; according to the concrete condition of system, the packet which source address is set provides may be the protected digit content product that the user orders.

2) provide the operation system of protected digit content product, should an authentication (ContentID) that the overall situation is unique be set for each digital product.Usually, the user is only consuming a digital content product sometime, so only the user by user interface with need be when respective server is communicated by letter by authentication (ContentID) location corresponding digital product, paying, apply for the copyright information (content key) of this digital product, the meaning that is to say this sign often is the communication process between the server, when sending the data to terminal, this sign packing is not sent alternatively so; If terminal is supported concurrent download, still can distinguish different content by URL, respectively file destination is downloaded to the different memory spaces of terminal, and bind with corresponding copyright information (content key).

For data flow, segmental file, the mode bit that needs is set in the extension bits of header file, be used for tagged keys to change state.General, following two states is arranged: packet unencryption, packet are encrypted; Or following four kinds of states: packet unencryption, packet have been encrypted and the key strategy does not change, packet has been encrypted and the key strategy will change and packet has been encrypted its key strategy and changed.So, usually, need not exceed two sign positions, for general data standard, be not difficult to find the expansion of header files of dibit.

Present embodiment provides a kind of packet to the SDCF data format to be decrypted the reasonable realization of processing at VOD program request and programme televised live.

As shown in Figure 1, in the decipher processing method of the digital property right management protection form (SDCF) of a kind of simplification that the embodiment of the invention provided, DRM comprises interconnected content-encrypt layer, mandate/key management layer, flow processing/user interface layer, customer management layer and DRM agency; Wherein, the content-encrypt layer is mainly finished the encryption of programme content, comprises that real-time stream encryption and file encrypt in advance; Mandate/key management layer mainly comprises RO management, empowerment management and KMS; Flow processing/user interface layer mainly comprises operation flow and business model processing and DRM user interface; Customer management layer mainly comprises Customer Tracking and authentication; The DRM agency mainly comprises RO administration module, key management module, content decryption module, supervision control module and player, browser etc., monitors to be provided with in the control module to broadcast preceding control submodule.Should be noted that, the strategy of whole system all should be subjected to a server unified allocation of resources, use a server that is called middleware to realize this function in embodiments of the present invention, clearly do not draw among middleware Fig. 1, this module is wanted and each module is had an effect with the work between collaborative each module, its effect mainly is a synergy, almost each module is all wanted and it carries out alternately, for the ease of discern, analysis.

Wherein, the nucleus module that is decrypted for the SDCF data format is content decryption module naturally, but say exactly, whole DRM Agent synergy, just realized for the deciphering of the packet of SDCF data format and the broadcast of respective program, wherein browser is used for inquiring about program, player plays program clear stream, and these two parts and deciphering have the comparison confidential relation, and present embodiment can be made more detailed description; And RO administration module, key management module, supervision control module three parts mainly are to be used for rights management, and present embodiment is not done too much and at large described, and only the function relevant with deciphering are made as giving a definition:

1) right objects RO can be applied for, be received, handle to the RO administration module, and can remove, recall RO.Wherein remove useless RO, handling RO, to overflow, recall operation such as RO all be for the better protection copyright information.

2) key management module is primarily aimed at programme televised live, and for raising speed, key management module is by the right objects verifying authorization and obtain content key CEK, sets up the quick indexing table of ContentID → Key in internal memory; When a certain right objects is crossed after date, key management module remove this right objects correspondence content key, in the quick indexing table of ContentID → Key, delete respective meta-data accordingly.

3) the supervision control module is regularly called RO administration module poll RO state, makes corresponding processing for expired RO; Periodic inspection DRM agency's time,, call the RO administration module and carry out the time synchronized calibration by ROAP agreement and server if inaccurate; Make regular check on the integrality of DRM Agent code, according to the seriousness of problem, make corresponding reaction etc. behind the discovery unsafe factor.Monitoring that control module guarantees the fail safe of DRM Agent, be the safety assurance of whole decryption processing, but present embodiment is mainly discussed the decryption processing process, just no longer this has been set off a discussion.

Three indexs in the SDCF data format, all be used to dispatch decryption processing, so present embodiment is described the realization of Play Control emphatically, Fig. 2 is the structure chart of broadcasting preceding control module of present embodiment just, especially VOD program request, present embodiment provides the decryption processing to VOD program request (ISMA data flow) and live (TS data flow) as mentioned above, the systematic unity that present embodiment provides two kinds of api interfaces that decryption processing is external, but inner handling process is different, below two kinds of patterns is separately discussed:

One, VOD file---ISMA data flow

According to the VOD file of SDCF regulation, promptly whether in the ISMA data flow, not identifying the bit-identify data flow is clear stream, and whether be clear stream to regulation DRM Agent in the present embodiment if differentiating data flow according to the RO of this program correspondence.The whole flow process relevant with decryption processing is as follows:

1) user inquires about program by EPG, and selects a certain program.

2) EPG sends to the preceding control module of broadcasting of DRM Agent with the URL and the programme content ID of user selected program correspondence.

Whether 3) the RO administration module is inquired about this machine according to the URL of program and programme content ID corresponding right objects RO.If there is not RO, just check whether authority application RO is arranged.If authority is arranged, DRM just applies for, obtains RO by EPG.If Agent can not apply for RO, prove that so data flow is a ciphertext, and user's authority is expired, processing reports an error.

4) have authority to play this program to broadcast if any the user before control module the URL of programme content is sent to player.

5) demultiplexing module of player is handled the digital content of different URL, carries out the processing and the encoding and decoding of data packet head and handles.

6) decryption engine obtains authority and decruption key from RO administrative office, and is decrypted broadcast.

Wherein, for being in the transitional file of key, it still is that old key is decrypted processing that Agent selects to use new key by different URL.

Two, flow in real time---the TS data flow

According to the real-time stream of SDCF regulation, promptly in the MPEG TS overIP data flow, whether sign position TSC (TransportScrambling Control) identification data stream is clear stream, and TSC sign position has only two, can realize on the extension bits of the packet header of any agreement.By the state of its sign as shown in Figure 3, thus DRM Agent whether can differentiate data flow according to TSC sign position be clear stream, identification key state.For the handling process of TSC as shown in Figure 4.The whole flow process relevant with decryption processing is as follows:

1) user inquires about program according to EPG, and selects a certain program.

2) EPG sends to DRM Agent with the URL and the programme content ID of user selected program correspondence.

3) DRM Agent inquires about the effective right objects RO whether this machine has this program according to the URL and the programme content ID of program.If do not have the RO of corresponding authority, just by certain mode application, obtain RO.If can not apply for RO, notice EPG user does not have rights of using, and EPG prompting user goes to order associated rights.

4) after DRM Agent determined that the user has the authority of watching this program, notice EPG user had the right to watch program.

5) EPG calls player, and player differentiates according to TSC sign position whether data flow is clear stream, if TSC is 00, data flow is a clear stream so, and the sign position of player is set to clear stream and plays, and the beginning broadcast program stops watching program until the user.Otherwise data flow is shielded, and the sign position of player is set to ciphertext and plays, and enters step 6).

6) player sends to the deciphering module of Agent with the data flow that receives, and as shown in Figure 5, Agent selects the strategy of deal with data according to the sign position of TSC:

A) when TSC sign position was 01 or 10, deciphering module was decrypted data with current key, and the data clear stream is sent to player plays.

B) when TSC sign position was 11, deciphering module was decrypted data with new key, and the data clear stream is sent to player plays.

C) when TSC sign position was 10 or 11, Agent checked whether oneself has obtained to comprise the right objects of new content key, if do not have, by the new right objects of ROAP agreement application by copyright management module.Apply for separating the encryption key that makes new advances by processing after the new right objects, and put it in the cipher key list of programme content ID correspondence.When the sign position is 11, give current key with new encryption key assignment.---this part belongs to the copyright processing module, has not set forth as emphasis here.

Should be noted that the corresponding operating of this step all is to obtain key by the cipher key list of programme content ID correspondence, with speed up processing.After monitoring that control module finds that the user has not had authority, can delete the associated metadata in the cipher key list of corresponding RO and programme content ID correspondence, and send message to EPG, EPG notifies the user to order corresponding authority.

Claims (8)

1, the decipher processing method of a kind of SDCF, its establish and platform comprise rights issuer, the middleware of the DRM agency and the DRM of set-top box, wherein the DRM agency comprise RO administration module, key management module, content decryption module, be provided with the supervision control module of controlling submodule before broadcasting and player, browser; It is characterized in that decipher processing method comprises the steps:

1) user selects program by user interface, obtains the URL of the unique program identification ContentID of the overall situation and this programme content;

2) broadcast preceding control module according to the RO of Content ID, and check authority in the local search correspondence; If do not search the failure of corresponding RO or scope check, terminal is then to rights issuer application copyright; If successfully apply for RO, then carry out scope check; If can not or can not apply for corresponding RO through scope check, set-top box then can report an error and return; If can pass through scope check, and obtain URL, decryption mode and the content key of corresponding digital content, then enter step 3);

3) content decryption module obtains corresponding RO from broadcasting preceding control module, and obtains decryption mode and content key, thereby finish decryption work according to the URL in the packet that transmits digital content.

2, the decipher processing method of SDCF according to claim 1 is characterized in that, the program in the described step 1) comprises VOD request program and programme televised live.

3, the decipher processing method of SDCF according to claim 1 is characterized in that, what play in the described step 1) is programme televised live, should add the transmission rule control bit of tagged keys state in packet.

4, the decipher processing method of SDCF according to claim 3, it is characterized in that, described transmission rule control bit is provided with two bit-identifies, respectively expression: program is not encrypted, program is normally encrypted, program is about to more new key, key new key more.

5, the decipher processing method of SDCF according to claim 1 is characterized in that, program is a general programs in the described step 1), and player is in described step 2) in control well after the authority, directly send to player; No longer pass through content decryption module.

6, the decipher processing method of SDCF according to claim 1 is characterized in that, program is about to more new key in the described step 1), and then the RO administration module need be applied for new RO to the backstage, in order to decryption content behind the replacing key.

7, the decipher processing method of SDCF according to claim 1, it is characterized in that, program has been changed key in the described step 1), and then content decryption module uses decryption mode and decruption key in the new right objects to carry out data processing, and deletes old RO.

8, the decipher processing method of SDCF according to claim 1, it is characterized in that, program is normally encrypted in the described step 1), content decryption module normal process then, promptly from the RO of this program correspondence, obtain decryption mode and content key, and use content key decrypts digital content under the algorithm of decryption mode by control module before broadcasting.

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