CN100358287C - Method for obtaining digital contents - Google Patents

Abstract

The present invention discloses a method for obtaining digital contents, which comprises the following steps: copyright objects (RO) are added with delineation for storing address of digital contents; the method sends the RO to terminal devices; the terminal devices obtain digital contents according to the storing address of digital contents. Users can directly obtain the digital contents according to the storing address of the digital contents in the RO when the users wrong delete the digital contents by various reasons after the use of the present invention, which is convenient for use by the users, and the users can accurately obtain DCF files corresponding to the digital contents, which ensures the correctness of the digital contents. The present invention also prevents newly downloaded digital contents from difficultly being used.

Description

A method of obtaining digital content

technical field

The present invention relates to Open Mobile Alliance Digital Rights Management (OMA DRM) technology, in particular to a method for obtaining digital content.

Background technique

OMA DRM is a system defined by the Open Mobile Alliance and used to control the use of downloaded digital content. The OMA DRM system has been widely supported by terminal/server equipment manufacturers and mobile operators, and has been widely used in downloading, MMS, streaming media and other business fields.

Figure 1 shows a schematic diagram of the OMA DRM system structure. As shown in Figure 1, the OMA DRM system includes a Content Publishing Center (CI), a Copyright Publishing Center (RI), a Certificate Authority (CA), and terminal devices. Among them: the terminal device is used to check the rights and control the consumption of DRM content; RI is used to send the copyright object (RO), and at the same time allows the protected digital content to be transferred and restored between different devices; CI is used to send the protected content ;CA is used to issue certificates for terminal devices to authenticate the legitimacy of terminal devices.

The Separate Delivery method is a delivery method based on the OMA DRM system. Fig. 2 is the architectural diagram of the separate transmission mode of the OMA DRM system. In the separate transmission method, it is necessary to encrypt and convert the digital content expressed in clear text into a DRM content format (DCF) file, and implement symmetric encryption on the digital content during the conversion to protect the digital content. Unless you have the content key (CEK), anyone else None of the obtained content can be used. Also, in the separate transmission mode, the RO and the protected content are transmitted separately. DCF files can be sent through various transmission channels such as download, MMS, and infrared, while ROs containing CEK are sent through safer transmission channels such as WAP Push and ROAP protocols. After the DCF file and the RO are downloaded to the terminal device through different channels, the terminal device controls the use of the DCF file according to the permissions and constraints defined in the RO.

Due to reasons such as limitation of storage capabilities of terminal devices, users often delete some digital content. However, users may often need these digital contents again. Moreover, due to the user's misoperation, the user may also delete some digital content that he does not want to delete. No matter what reason the user deletes the digital content, usually the user does not delete the RO.

In many cases, users need to retrieve digital content. For this reason, the user can log in to the website of the content provider and download the digital content again, but this will have the following defects:

1. After the user logs in to the website of the content provider, he needs to continuously browse the webpage to find and search the storage path of the digital content, which will make the user's operation very troublesome. Moreover, allowing the user to search for the storage path of the digital content does not fully guarantee the correctness of the path, and the digital content searched by the user is not necessarily the digital content that the user wants to obtain.

2. For digital content protected by OMA DRM, since the digital content is encrypted and packaged into a DCF file, and only the content identification (Content ID, CID) contained in the DCF file is associated with the CID contained in the RO, the DCF can be found The RO corresponding to the file. Therefore, if a dynamic generation method is used to generate the DCF file and the CID contained in the RO when the user downloads for the first time, even if the user finds the corresponding DCF file through the website, the CID contained in the newly downloaded DCF file is the same as the original RO. The CIDs contained in the RO are likely to be different, so that the newly downloaded DCF file cannot be used because it cannot be associated with the RO.

Therefore, the method of re-downloading digital content from a website will increase the complexity of user operations. And since the correctness of the downloaded DCF file cannot be guaranteed, the DCF file downloaded by the user may be unusable. Moreover, even if the downloaded DCF file is correct, the newly downloaded DCF file may not be usable because the CID contained in the newly downloaded DCF file may not be related to the CID contained in the original RO.

Contents of the invention

In view of this, the main purpose of the present invention is to propose a method for obtaining digital content, so that users can conveniently obtain digital content according to RO.

In order to achieve the above object, technical solution of the present invention is achieved in that way:

A method for obtaining digital content, comprising the steps of:

A. Add a description of the digital content storage address in the RO, and send the RO to the terminal device;

B. After obtaining the RO, the terminal device obtains the digital content according to the storage address of the digital content.

In step A, adding a description of the digital content storage address in the RO, and sending the RO to the terminal device is as follows: the copyright issuance center adds a description of the digital content storage address in the RO, and the copyright issuance center sends it to the terminal device The RO.

The digital content storage address is a (Uniform Resource Locator) URL address.

Adding the description of the digital content storage address in the RO described in step A is: when an RO corresponds to a digital content, add a sub-element describing the digital content storage address in the <Context> element in the basic mode of the RO.

Adding the description of the storage address of the digital content in the RO described in step A is: when the digital content is a composite media object, and an RO corresponds to a composite media object, the <Context> in the basic mode of the RO A sub-element describing the storage address of the digital content is added to the element.

Adding the description of the storage address of the digital content in the RO mentioned in step A is: when the said digital content is not less than one media object, and when one RO corresponds to not less than one media object, in the RO An element describing the storage address of the digital content is added to the <Context> sub-element of each <Asset> element in the protocol mode.

The acquisition of digital content according to the digital content storage address described in step B is as follows: the terminal device sends a request for obtaining digital content to the content publishing center according to the digital content storage address, the content publishing center returns information according to the request, and the terminal device sends a request according to the returned information Get digital content.

The returned information is a file in DCF format, a download descriptor, a WAP page, a WEB page, or HTTP redirection information.

The acquisition of digital content according to the digital content storage address in step B is: the terminal device sends a request for obtaining digital content to the content distribution center according to the digital content storage address, and the content distribution center directly sends the digital content to the terminal device.

Before step B, the digital content corresponding to the RO no longer exists in the terminal device.

The acquisition of digital content according to the storage address of the digital content described in step B is: when the digital content corresponding to the RO exists in the terminal device, it is judged whether to confirm to re-acquire the digital content, if so, the terminal device sends the digital content according to the storage address of the digital content to The content publishing center sends out a request for acquiring digital content, and the content publishing center sends the digital content to the terminal device; if not, this process ends.

The acquisition of digital content according to the storage address of the digital content described in step B is: selecting the element describing the storage address of the digital content, and sending a request to the content publishing center to obtain the digital content according to the storage address of the digital content corresponding to the selected element, The content publishing center sends digital content to the terminal device according to the request.

The digital content is a DCF file. In step A, the description of the content identification CID of the DCF file is further added in the RO, and the CID of the DCF file obtained in step B is the same as that of the DCF file added in the RO. CIDs are associated.

In step B, obtaining the digital content according to the digital content storage address is as follows: user A connects to the content release center/copyright release center according to the digital content storage address, purchases the digital content and the RO of the digital content on behalf of user B, and the content release center/copyright The publishing center sends the digital content and its RO to user B.

The digital content is Multipurpose Internet Mail Extensions (MIME) type media.

The media of the MIME type is ringtone or multimedia information or streaming media.

It can be seen from the above technical solutions that in the present invention, the description of the storage address of the digital content is firstly added in the RO, and then the digital content is obtained according to the storage address of the digital content in the RO when necessary. Therefore, after applying the present invention, when the user deletes the digital content by mistake due to various reasons, it is not necessary to go directly to the website to search for the digital content, but can directly obtain the digital content according to the storage address of the digital content in the RO. The use of the user is facilitated, and the convenient acquisition of digital content according to the RO is realized.

Moreover, since the address of the digital content has been determined in the RO in advance, the user can accurately obtain the digital content corresponding to the digital content, thereby ensuring the correctness of the digital content.

At the same time, the present invention increases the description of the CID of the DCF file in the RO, and associates the CID of the obtained DCF file with the CID of the DCF file added in the RO, thereby avoiding the situation that the newly downloaded digital content cannot be used .

Description of drawings

FIG. 1 is a schematic structural diagram of an OMA DRM system in the prior art.

FIG. 2 is an architecture diagram of separate sending modes in the OMA DRM system in the prior art.

FIG. 3 is a flow chart of the method for acquiring digital content in the present invention.

Fig. 4 is a flowchart of a method for acquiring digital content according to the first embodiment of the present invention.

Fig. 5 is a flowchart of a method for acquiring digital content and its copyright according to the second embodiment of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The main idea of the present invention is to add a description of the storage address of the digital content in the RO in advance. Store the address and retrieve the digital content again.

FIG. 3 is a schematic flow chart of acquiring digital content in the present invention. As shown in Figure 1, the following steps are included:

Step 301: Add a description of the storage address of the digital content to the RO, and send the RO to the terminal device.

Before sending the RO to the terminal device, the copyright center firstly adds a description of the storage address of the protected digital content to the RO.

The description of the storage address of the digital content can be added by extending the context model (Context Model) of the copyright description language. In the copyright description language, the context model (ContextModel) provides metadata information about the RO. With the help of the context mode, the additional information of the RO can be added to the basic mode, the protocol mode, and the restricted mode. In the present invention, the description of the digital content address is firstly added in the context mode. For example: a <contentIssuer> element can be added, the <contentIssuer> element is a URL address pointing to digital content, and the format used complies with the specification RFC2396.

In the OMA DRM1.0 specification, it is required that one RO can only correspond to one digital content, that is, RO and DCF files are one-to-one; while the OMA DRM2.0 specification supports composite ROs, that is, multiple digital content can be described in one RO. For copyright information, the multiple digital contents may be a composite media object, or multiple independent media objects. In view of the above situation, how to add a description of the storage address of the digital content in the RO is described below.

(1) One RO corresponds to one digital content

When an RO corresponds to a digital content, add a description of the digital content address in the <Context> element under the Foundation Model of the RO. For example: add a <ContentIssuer> sub-element to the <Context> element in the basic mode of RO. The <ContentIssuer> sub-element is a URL address pointing to digital content, and the format used complies with the specification RFC2396.

(2) One RO corresponds to one composite media object

When an RO corresponds to a composite media object, add a description of the digital content address in the <Context> element under the foundation model (FoundationModel) of the RO. For example: Add the <ContentIssuer> sub-element to the <Context> element under the "Foundation Model" of the RO. This sub-element is a URL address pointing to the digital content, and the format used complies with the specification RFC2396.

(3) One RO corresponds to multiple media objects

For the case that one RO corresponds to multiple media objects, add a description of the address of the digital content in the <Context> sub-element of each <Asset> element under the agreement model (AgreementModel) of the RO. For example: Add a <ContentIssuer> element to the <Context> sub-element of each <Asset> element in RO’s agreement mode (Agreement Model), where each <ContentIssuer> element is a URL address pointing to digital content, and each The format used by the <ContentIssuer> element complies with the specification RFC2396. At this time, there will be multiple <ContentIssuer> elements, and the values of each different <ContentIssuer> element are different.

After adding the description of the storage address of the digital content in the RO, when the user downloads the digital content for the first time, the content center sends the digital content to the user, and the copyright center sends the user a description of the storage address of the digital content and communicates with the user. The RO corresponding to the digital content. At this point, the terminal device can obtain the RO and the digital content. Afterwards, if the user deletes the digital content due to accidental deletion or other reasons, as long as the RO is not deleted, the user can conveniently obtain the digital content again according to the storage address of the digital content in the RO.

Step 302: The terminal device acquires the digital content according to the storage address of the digital content.

When a user wants to obtain digital content, the user can obtain the digital content according to the storage address of the digital content. For example: when the digital content corresponding to the RO does not exist, the terminal device reacquires the digital content according to the storage address of the digital content in the RO. Even if the digital content already exists in the terminal device, the terminal device can still use the storage address of the digital content to obtain the digital content again according to the needs of the user. Preferably: when the digital content corresponding to the RO does not exist, first the terminal device interprets the RO to obtain the content storing the digital address, and then the terminal device initiates a Get request according to the URL link pointed to by the <ContentIssuer> element. Preferably, the terminal device may prompt the user before initiating the Get request, so that the user can choose whether to confirm the initiation of the Get request. Where one RO corresponds to multiple media objects, if the multiple digital contents corresponding to the RO do not exist, the user can choose to apply a specific <ContentIssuer> element to initiate a request.

Preferably, when the digital file corresponding to the RO exists, if the user actively requests to initiate a Get request according to the URL link pointed to by the <ContentIssuer> element, the terminal device supports it. More preferably, when there are multiple URL links, the user is allowed to select a specific <ContentIssuer> element to initiate a request.

After the terminal device sends a Get request, CI/RI will return the corresponding return information, and the type of the returned information can be DCF format file, download descriptor, WAP page, WEB page, HTTP redirection, HTTP error message, etc. The terminal device judges whether it supports the MIME type contained in the returned information according to the type of the returned information. If it does not support it, it will report an error to the user and give up subsequent processing; if it supports it, it will perform subsequent processing until the download is successful or the user gives up.

Preferably, a description of the content identifier (CID) of the DCF file is added to the <ContentIssuer> element, and the CID is used as a parameter of the URL in the <ContentIssuer> element. For example, the URL can be: http://drm.huawei.com/drm ? CID=XXXXXXXXXX . When the terminal device sends a request according to the URL, it will report the CID to CI/RI, and CI/RI will generate the CID associated with the DCF file according to the reported CID, so as to ensure that the CID of the DCF file returned by CI/RI is the same as The CID included in the <ContentIssuer> element is associated, so it is possible to avoid the situation that the newly obtained DCF file cannot be used because the CID is not associated.

Preferably, the ContentIssuer element is ignored if the terminal device cannot interpret the ContentIssuer element.

In the separate transmission method of OMA DRM, it is necessary to encrypt and convert the digital content represented by plain text transmission into a DCF file.

Fig. 4 is a flowchart of a method for acquiring digital content according to the first embodiment of the present invention. As shown in Figure 4, the following steps are included:

Step 401: The user deletes the DCF file due to various reasons such as misoperation, but the RO of the DCF file is not deleted.

Step 402: the user requests the terminal device to restore the DCF file.

Steps 403 to 404: The terminal device initiates a Get request to the CI according to the URL contained in the <ContentIssuer> element in the RO, and the CI returns the WAP/WEB page after receiving the Get request.

Step 405: the terminal device displays the WAP/WEB page to the user, and the user can choose whether to confirm the download according to the prompt of the WAP/WEB page.

Step 406-Step 408: Confirm the download on the WAP page/WEB page displayed by the terminal device, the terminal device initiates a digital content download request to the CI, and the CI returns the DCF file. Wherein, when only the original digital content is kept on the CI without DCF, the CI sends the original digital content to the RI for encryption, packs it into a DCF file, and then sends the DCF file to the terminal device.

Step 409: The terminal device downloads and saves the DCF file, associates the downloaded DCF file with the RO, and the user can reuse the DCF file.

Utilizing the present invention, users can not only obtain deleted digital content according to RO, but also enable other users to experience digital content by purchasing digital content and its copyright for other users. For example: in the process of experiencing digital content, user A discovers a particularly exciting digital content, and user A wants to share the digital content with user B. Since the digital content is protected by DRM, user A wants to purchase the digital content and its RO for user B. Fig. 5 is a flowchart of a method for acquiring digital content and its copyright according to the second embodiment of the present invention. As shown in Figure 5, it includes the following steps:

Steps 501 to 504: User A sends a request to purchase copyright and digital content, and user A's terminal device initiates a request to CI/RI based on the URL address contained in the <ContentIssuer> element in the RO of the digital content that user A already owns. Get request, CI/RI returns the WAP/WEB page, and the terminal device displays the WAP/WEB page to the user.

Steps 505-507: User A confirms the purchase of the digital content on the WAP/WEB page, and enters user B's receiving number, and the WAP/WEB page sends user B's receiving number to CI/RI, and CI/RI is based on user B's receiving number. The receiving number sends digital content and its RO to user B's terminal device, or CI/RI sends digital content and its RO connection address to user B's terminal device according to user B's receiving number, so that user B can also experience the digital content .

Step 508: User B's terminal device prompts that user B has obtained the digital content and its copyright.

In the above process, preferably, the digital content can be any type of MIME media file. More preferably, the digital content may be ringtones, multimedia information, or streaming media.

In the above process, the second embodiment of the present invention is described by taking user A purchasing digital content for a user B as an example, but in fact, user A can also purchase digital content and its copyright for multiple users at the same time.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (16)

1, a kind of method of obtaining digital content is characterized in that, may further comprise the steps:

A, in right objects RO, increase description, and send this RO to terminal equipment to the digital content storage address;

After B, terminal equipment obtain this RO, obtain digital content according to described digital content storage address.

2, method according to claim 1, it is characterized in that, the described description that in RO, increases the digital content storage address of steps A, and send this RO to terminal equipment and be: in RO, increase description by copyright issue center, and the mind-set terminal equipment sends this RO in being issued by copyright the digital content storage address.

3, method according to claim 1 is characterized in that, described digital content storage address is URL address, unified resource location.

4, method according to claim 1, it is characterized in that, steps A is described to increase being described as the digital content storage address in RO: when the corresponding digital content of a RO, under the basic schema of RO＜Context〉increase the daughter element of describing the digital content storage address in the element.

5, method according to claim 1, it is characterized in that, steps A is described to increase being described as the digital content storage address in RO: when described digital content is a compound media objects, and during the corresponding compound media objects of RO, under the basic schema of RO＜Context〉increase the daughter element of describing the digital content storage address in the element.

6, method according to claim 1, it is characterized in that, steps A is described to increase being described as the digital content storage address in RO: when described digital content is to be no less than one media object, and when a RO to should be no less than one media object the time, each under the protocol mode of RO＜Asset〉element＜Context increase the element of describing the digital content storage address in the daughter element.

7, method according to claim 1, it is characterized in that, step B is described to be obtained digital content according to the digital content storage address and be: terminal equipment sends the request of obtaining digital content according to described digital content storage address to the content release center, return information is asked according to this in the content release center, and terminal equipment obtains digital content according to this return information.

8, method according to claim 7 is characterized in that, described return information is file, Download Descriptor, the WAP page, the WEB page or the HTTP redirection information of DCF form.

9, method according to claim 1, it is characterized in that, step B is described to be obtained digital content according to the digital content storage address and be: terminal equipment sends the request of obtaining digital content according to described digital content storage address to the content release center, and digital content is directly sent to this terminal equipment in the content release center.

10, method according to claim 9 is characterized in that, before step B, digital content corresponding with RO in this terminal equipment does not exist.

11, method according to claim 1, it is characterized in that, step B is described to be obtained digital content according to the digital content storage address and is: when digital content corresponding with RO in the terminal equipment exists, judge whether to confirm to obtain again this digital content, if, terminal equipment sends the request of obtaining digital content according to described digital content storage address to the content release center, and this terminal equipment of mind-set sends digital content in the content release; If not process ends then.

12, method according to claim 6, it is characterized in that, step B is described to be obtained digital content according to the digital content storage address and be: the element to described description digital content storage address is selected, and send the request of obtaining digital content to the content release center according to the digital content storage address of the element correspondence of choosing, the content release center is sent digital content according to this request to terminal equipment.

13, method according to claim 1, it is characterized in that, described digital content is the DCF file, further increase the description to the content identification CID of this DCF file in the steps A in RO, the CID of the described DCF file that obtains of step B is associated with the CID of described this DCF file that increases in RO.

14, method according to claim 1, it is characterized in that, step B is described to be obtained digital content according to the digital content storage address and be: user A connects content release center/copyright issue center according to described digital content storage address, replace user B to buy the RO of digital content and this digital content, mind-set user B sends digital content and RO thereof in content release center/copyright issue.

According to claim 1 or 14 described methods, it is characterized in that 15, described digital content is the medium of multiduty internet mail extension protocol mime type.

16, method according to claim 15 is characterized in that, the medium of described mime type are the tinkle of bells or multimedia messages or Streaming Media.

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