Method for joining user domain and method for exchanging information in user domain

The present invention relates to digital rights management (hereinafter abbreviated as DRM), and particularly relates to a user domain joining method for digital rights management and an information exchange method for exchanging information within the user domain.

The OMA (Open Mobile Alliance), a mobile application software standardization organization, is discussing the standardization of the'OMA DRM extension for Secure Content Exchange (hereinafter abbreviated as OMA DRM SCE), which is an extension of the existing OMA DRM version 2.0. In OMA DRM SCE, each user device joins a user domain through a domain enforcement agent (hereinafter abbreviated as DEA) on behalf of the rights issuer (hereinafter abbreviated as RI). ) Is defined so that it can be done.

Figure 1 is a reference diagram showing the domain enrollment procedure for OMA DRM version 2.0. In Figure 1, the 2-pass Join Domain Protocol required for user devices supporting OMA DRM version 2.0 to use a domain-based rights object (hereinafter abbreviated as RO). The processing operation of is illustrated.

As shown, the user device uses a two-step domain join protocol to request a rights issuer (RI) to join a domain. The Rights Issuer (RI) requests the OCSP Responder (Online Certificate Status Protocol Responder) for the status of the certificate. If the status of the certificate is responded, it responds to the user domain subscription request of the user device.

At this time, if the state of the above-mentioned certificate is'good', it means that the certificate is valid, and if it is'revoked', it means that the certificate is not permanently discarded or suspended. Means'unknown'means that there is no known information about the certificate.

The authority issuer determines whether or not to join the user domain of the user device based on the status information of the returned certificate and responds. The domain-based rights object (RO) becomes available to the user device through the process of joining the user domain.

Figure 2 shows the process for multiple user devices supporting OMA DRM version 2.0 to use domain-based rights objects (ROs). In FIG. 2, the user devices D1, D2, and D3 are registered with the rights issuer using the 4-step registration protocol, and join the specific user domain using the 2-step domain joining protocol.

After that, the user device D1 acquires the rights object (RO), that is, the content and the rights from the rights issuer using the 2-pass Rights Object Acquisition Protocol, and belongs to the same user domain. By transmitting this to the user devices D2 and D3, the rights object (RO) is transmitted to the user devices D2 and D3. This makes the rights object (RO) available to user devices D2 and D3.

On the other hand, since the user device D4 is not subscribed to the user domain to which the user device D1 belongs, the user device D4 needs to use the right object (RO) transmitted by the user device D1 to the user device D4. User device D4 must register with the rights issuer (RI) using the 4-step registration protocol and join the user domain to which user device D1 belongs using the 2-step domain join protocol.

On the other hand, in OMA DRM SCE, which is an extension of OMA DRM version 2.0 (see Figures 1 and 2), each user device can join the user domain through the domain enforcement agent (DEA) instead of the rights issuer (RI). it can. However, when joining a user domain using the two-step domain joining protocol (see Figure 1) defined in OMA DRM version 2.0 with OMA DRM SCE, the following problems may occur.

First, when performing security communication between a plurality of devices in the same user domain, the user devices must first be authenticated and a shared key must be set. However, when using an existing authentication method using OCSP or the like, the load on the user device increases, and the advantage of communication between members within the same user domain disappears. In addition, the only information that two communicating user devices have in common is the domain rights object (Domain RO). Since the Domain Key stored in the domain rights object is information that is known to all members belonging to the same user domain, the domain key is used to encrypt communication between two user devices. In that case, there is a problem that communication security cannot be guaranteed.

Second, when security communication is performed between the user device and the domain enforcement agent (DEA), there is no key information that the user device and the domain enforcement agent have in common. Therefore, in order to perform encrypted communication between the user device and the domain execution agent, a new security session must be specified using the existing authentication method, and communication security is the same as in the first case. There is a problem that it cannot be guaranteed.<patcit num="1"><text>Japanese Patent Application Laid-Open No. 2008-52735</text></patcit>

<p> The present invention has been made to solve the above problems, and is secure between a user device and a domain enforcement agent (DEA) in a digital rights management environment, and between user devices belonging to the same user domain. The purpose is to provide a method of information security in a digital rights management (DRM) environment that can form a session. In particular, an object of the present invention is to provide a user domain joining method and an information exchange method for digital rights management.</p>

<p> The user domain joining method according to the embodiment of the present invention is a domain that enables a secure session to be formed between a user device and a domain enforcement agent (DEA) between user devices belonging to the same user domain. It is characterized by exchanging session key information.</p><p> On the other hand, in the method of exchanging information between the user device and the domain execution agent according to another embodiment of the present invention, the domain session key information exchanged in the process of joining the user domain is used between the user device and the domain execution agent. It is characterized by encrypting the information transmitted in.</p><p> On the other hand, the method of exchanging information between user devices according to another embodiment of the present invention is information transmitted between the user devices using specific domain session key information issued only to the user devices exchanging information. It is characterized by encrypting.</p><p> More specifically, according to one embodiment of the present invention, the object is a method for joining a user domain for digital rights management, the first object to be used for security in a domain execution agent in which a user device manages a user domain. 1 The step of transmitting a user domain join request message including domain session key information to the domain execution agent, and the step of storing the first domain session key information and executing the process for the user domain join request message by the user device. It is achieved by receiving a user domain join response message containing second domain session key information for confirmation of receipt from the domain enforcement agent, and a user domain join method including.</p><p> On the other hand, according to another embodiment of the present invention, the object is to allow the user device or the domain enforcement agent to interact with each other in a method of exchanging information between a user device and a domain enforcement agent for digital rights management. Domain session shared between the stage of encrypting and transmitting information to be transmitted using key information, and the domain session shared between the user device or the domain execution agent that received the encrypted information. It is achieved by an information exchange method including a step of decrypting the encrypted information using the key information.</p><p> On the other hand, according to another embodiment of the present invention, the object is to join a user domain and share domain session key information with a domain execution agent in a method of exchanging information between user devices for digital rights management. The stage in which the first user device identifies the second user device with which information is to be exchanged with the domain execution agent and requests new domain session key information, and the domain execution agent causes the first and second users. A step of generating new domain session key information for exchanging information between user devices and transmitting it to the first and second user devices, and a new stage received by the first and second user devices from the domain execution agent. Achieved by information exchange methods, including the step of exchanging information with each other using domain session key information.</p>

<p> According to the present invention, a secure session is formed between a user device and a domain enforcement agent (DEA) in a digital rights management environment by using domain session key information between user devices belonging to the same user domain. It is possible to effectively guarantee the security of communication within the domain.</p>

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In explaining the present invention, if it is determined that a specific description of the related known function or configuration may obscure the gist of the present invention, the detailed description thereof will be omitted. Further, the terms described later are terms defined in consideration of the functions of the present invention, and may change depending on the intentions or customs of the user and the operator. Therefore, the definition must be based on the content throughout this specification.

(First Embodiment) FIG. 3 is a diagram showing an outline of a user domain joining request / response procedure according to the first embodiment of the present invention. In FIG. 3, the user device 100 sends a domain join request for a specific user domain to the domain execution agent (DEA) 200 that manages the user domain, and the domain execution agent (DEA) 200 that receives the request is the user. The user domain subscription process of the user device 100 is performed by processing whether or not the user domain can be subscribed to the specific user domain requested by the device 100 and returning the response to the user domain subscription to the user device 100. As the user device 100, various portable communication devices having communication functions defined by OMA DRM version 2.0, such as mobile phones and portable personal computers, can be applied.

In the present embodiment, a domain that enables a secure session to be formed between a user device 100 and a domain execution agent (DEA) 200 in the process of joining a user domain between user devices belonging to the same user domain. Define a new protocol for exchanging session key information.

FIG. 9 is a diagram showing an example of a user domain join request message 900 including a function for exchanging domain session key information. As shown in FIG. 9, the user domain subscription request message 900 corresponding to the digital rights management environment according to the present embodiment includes a header 901, a payload 902, and a tail 903. The payload 902 includes device identification information 902a, domain identification information 902b, right issuer identification information 902c, time information 902d, signature information 902e, authentication information 902f, device nonce information 902g, and the like. 1 Contains domain session key information 902h.

Here, the device identifier (Device Identifier) 902a is information for identifying the user device 100, and the domain identifier information (Domain Identifier) 902b is for identifying the user domain that the user device 100 desires to join. It is information, and the Right Issuer Identifier 902c is information for identifying the right issuer who distributed the digital right. The time information 902d is information that stores the time when the user device 100 requests to join the user domain.

The first domain session key information 902h is a cipher that enables a secure session to be formed between a user device 100 and a domain execution agent (DEA) 200 between user devices belonging to the same user domain. It is the secret key information for security used for the conversion. At this time, the first domain session key information 902h can be used as a key value of the symmetric key algorithm or as a mediator (Seed) for deriving the symmetric key value.

On the other hand, the payload 902 of the domain join request message 900 is a signature information (Signature) 902e for non-repudiation, an authentication information (Certificate Chain) 902f for authentication, and an arbitrary to prevent a reply attack. It also contains 902g of Device Nonce information for storing the value of.

FIG. 10 is a diagram showing an example of a user domain join response message 1000 including a function of exchanging domain session key information. As shown in FIG. 10, the user domain subscription response message 1000 corresponding to the digital rights management environment according to the present embodiment includes a header 1001, a payload 1002, and a tail 1003. The payload 1002 includes status information 1002a, device identification information 1002b, domain identification information 1002c, right issuer identification information 1002d, domain information 1002e, signature information 1002f, authentication information 1002g, device nonce information 1002h, and so on. Includes OCSP response information 1002i and second domain session key information 1002J.

Here, the status information (Status) 1002a means permission to join the user domain of the user device when it is'Success' as information for whether or not to join the user domain, and refuses to join the user domain otherwise. Means. The device identification information 1002b is information for identifying the user device 100. The domain identification information 1002c is information for identifying the user domain requested by the user device 100 to join. The right issuer identification information 1002d is information for identifying the right issuer (RI) who has distributed the digital right (Digital Right). The domain information 1002e is the registration information of the user domain requested to join.

The second domain session key information 1002j is a security used for encryption that enables a secure session between the user device 100 and the domain enforcement agent (DEA) 200 to form a secure session between user devices belonging to the same user domain. Information for. In particular, the second domain session key information 1002j is used to confirm the success or failure of receiving the first domain session key information 902h transmitted from the user device 100 for security. The second domain session key information 1002j can be used as a key value of the symmetric key algorithm or as a mediator (Seed) for deriving the symmetric key value.

On the other hand, the payload 1002 of the user domain join response message 1000 contains signature information 1002f for non-repudiation, authentication information 1002g for authentication, and device nonce information for storing arbitrary values to prevent response attacks. Including 1002h and more. In addition, the payload 1002 of the user domain join response message 1000 further includes Certificate Status information 1002a. The status information 1002a of this certificate is the information obtained by requesting the OCSP responder.

FIG. 4 is a flowchart showing a user domain joining method for digital rights management according to the first embodiment of the present invention. This flowchart shows a procedure for a user device corresponding to a digital rights management environment to exchange a protocol as shown in FIGS. 9 and 10 with a domain enforcement agent (DEA) in order to join a user domain. Is.

First, the user device 100 transmits a domain join request message 900 including the first domain session key information 902h for security to the domain execution agent (DEA) (S110). At this time, the user domain subscription request message 900 further includes device identification information 902a for identifying the user device 100 and domain identification information 902b for identifying the user domain desired to join.

Next, the domain execution agent (DEA) 200 that receives the user domain join request message 900 from the user device 100 saves the first domain session key information 902h and executes the process for the domain join request (S120). The process for a user domain join request is to determine whether or not to join the user device to a specific user domain, for example, the user domain requested by the user device 100.

When the processing for the domain join request is completed, the domain execution agent (DEA) 200 transmits the domain join response message 1000 including the second domain session key information 1002j to the user device 100 (S130). The domain join response message 1000 includes join acceptance / rejection information for the specific user domain of the user device 100.

The first domain session key information 902h and the second domain session key information 1002j described above provide a secure session between the user device 100 and the domain execution agent (DEA) 200 between user devices belonging to the same user domain. Security information used for encryption that allows it to be formed. This information is exchanged and shared between the user device 100 and the domain enforcement agent (DEA) 200 in the process of requesting to join the user domain corresponding to the digital rights management environment and responding to the request.

More specifically, the first domain session key information 902h is private key information used for security between the user device 100 and the domain execution agent 200, and is used for the user device 100 and the domain execution agent 200, respectively. It will be saved. The second domain session key information 1002j is information for the domain execution agent 200 to confirm the success or failure of normal reception of the first domain session key information 902h, and has a value corresponding to the first domain session key information 902h. .. The second domain session key information 1002j corresponding to the first domain session key information 902h can be applied in various ways.

As an example, the domain execution agent 200 can transmit to the user device 200 as the second domain session key information 1002j having the same value (for example, A) as the first domain session key information 902h. At this time, the first domain session key information 902h can be used as a key value of a symmetric key algorithm for use for security, or can be used as a mediator (Seed) for deriving the key value.

Further, as another example, the domain execution agent 200 can transmit to the user device 100 as the second domain session key information 1002j having the value converted using the first domain session key information 902h. At this time, the value converted using the first domain session key information 902h (for example, the result value of the one-way function) is used as the key value of the symmetric key algorithm for security. Alternatively, it can be used as a seed to derive the key value.

Further, as another example, the domain execution agent 200 can be transmitted to the user device 100 as the second domain session key information 1002j having an arbitrary value (for example, B) generated internally. At this time, the user device 100 generates a value converted using the first domain session key information 902h and the second domain session key information 1002j received from the domain execution agent 200, and is symmetrical for using this value for security. It can be used as a key value in a key algorithm or as a seed to derive a key value.

Further, as another example, the domain execution agent 200 uses a value (A) possessed by the first domain session key information 902h and an arbitrary value (B) generated by the domain execution agent 200 (for example, a value converted by the domain execution agent 200). f (A, B)) can be generated and this value can be transmitted to the user device 100 as the second domain session key information 1002j. At this time, the above-mentioned value can be used as a key value of a symmetric key algorithm for use for security, or can be used as a medium (Seed) for deriving the key value.

That is, in the above-mentioned example, the value (A) possessed by the first domain session key information 902h, the value (B) possessed by the second domain session key information 1002j, or the first and second domain session key information 902h and 1002j, respectively. The value (f (A, B)) converted using the possessed values (A) (B) can be used as the key value of the symmetric key algorithm or as the mediator (Seed) for deriving the key value. it can.

The above-mentioned examples of the first and second domain session key information 902h and 1002j are merely examples, and various modifications can be made according to the intention of the designer. As a result, thereafter, the values converted using the first domain session key information 902h, the second domain session key information 1002j, or the first and second domain session key information 902h, 1002j are converted by the user device 100 and the domain execution agent ( By using it for encryption and decryption of information transmitted between user devices belonging to the same user domain with DEA) 200, a secure session can be formed between these user devices. By forming this session, it will be possible to maintain communication security in response to a digital rights management (DRM) environment.

(Second embodiment) FIG. 5 is a diagram showing an outline of information exchange processing between the user device 100 and the domain execution agent 200 according to the second embodiment of the present invention. The domain session key information is exchanged between the user device 100 and the domain execution agent 200 through the user domain joining procedure described in FIGS. 3 and 4, and the domain session key information is shared as a private key prior to the information exchange. .. At this time, the information may be encrypted and transmitted using the domain session key information shared between the user device 100 and the domain execution agent 200, and the received information may be decrypted using this session key information. it can.

That is, in the information exchange method between the user device 100 and the domain execution agent 200 for digital rights management, the user device 100 or the domain execution agent 200 that has completed the domain joining procedure share the domain session key information with each other. The information to be transmitted can be encrypted and transmitted using. The user device 100 or the domain execution agent 200 that has received the encrypted information can decrypt the encrypted information by using the domain session key information shared by each other. At this time, as the domain session key information, the first domain session key information 902h, the second domain session key information 1002j, or the first and second domain session key information 902h, 1002j are used according to various examples as described above. The converted value etc. is used.

As a result, other members inside and outside the user domain do not know the domain session key information shared between the user device 100 or the domain execution agent 200 that has completed the domain joining procedure, so that the user device 100 and the domain execution agent 200 The security of the information transmitted between them is guaranteed.

FIG. 6 is a flowchart showing a method of exchanging information between the user device 100 and the domain execution agent 200 according to the second embodiment of the present invention. In this embodiment, information is encrypted and used in a digital rights management environment with domain session key information exchanged between the user device 100 and the domain enforcement agent 200 through protocols such as those shown in FIGS. 9 and 10. It shows the procedure for decryption.

First, the information transmitted is encrypted using the domain session key information shared by the user device 100 or the domain execution agent (DEA) 200 (S210). At this time, the domain session key information shared between each other is exchanged with each other in the process of processing the user domain joining request between the user device 100 and the domain execution agent 200. The domain session key information shared between each other is the first domain session key information 902h included in the domain join request message 900 (see Fig. 9) transmitted by the user device 100 to the domain execution agent (DEA) 200, or domain execution. It contains the second domain session key information 1002j contained in the user domain join response message 1000 (see Figure 10) transmitted by the agent (DEA) 200 to the user device 100.

The first domain session key information 902h is private key information used for security between the user device 100 and the domain execution agent 200, and is stored in the user device 100 and the domain execution agent 200, respectively. The second domain session key information 1002j is information for the domain execution agent 200 to confirm the success or failure of normal reception of the first domain session key information 902h, and has a value corresponding to the first domain session key information 902h. ..

As a result, the user device 100 and the domain execution agent 200 share the first domain session key information 902h and the second domain session key information 1002j, and share the shared first and second domain session key information 902h, 1002j. Information can be exchanged more securely by using the information to be encrypted and transmitted.

On the other hand, the user device receives the encrypted information scan 100 or domain enforcement agent (DEA) 200, the first and second domain session key 902h is shared, decrypts the information received with 1002J ( S220). At this time, the shared first and second domain session key information 902h, 1002j is used as a key value of the symmetric key algorithm for security, or is used as a mediator (Seed) for deriving the symmetric key value. can do. The shared first and second domain session key information 902h, 1002j can be the first domain session key information 902h, the second domain session key information 1002h, or the first and second domains, depending on various examples of user domain joining methods. It can be used for converted values of session key information 902h and 1002j.

As a result, the domain session key information exchanged and shared in advance in the domain joining request and response process is used for encryption and decryption of the information exchanged between the user device 100 and the domain execution agent 200. A secure session can be formed between the user device 100 and the domain execution agent 200, and communication security corresponding to the digital rights management environment can be maintained.

(Third embodiment) FIG. 7 is a diagram showing an outline of information exchange processing between user devices belonging to the same user domain according to the third embodiment of the present invention. The domain session key information is exchanged between the user device 100 and the domain execution agent 200 through the user domain joining procedure described in FIGS. 3 and 4, and the domain session key information is shared as a private key prior to the information exchange. .. In FIG. 7, when information is exchanged between the first and second user devices 300,400 belonging to the same user domain, it is already shared between the first and second user devices 300,400 that are trying to exchange information. A method of requesting new domain session key information separately from the domain session key information and exchanging information between the first and second user devices 300 and 400 using the new domain session key information is shown.

That is, they belonged to the same user domain by encrypting and decrypting the information using new domain session key information that is used only between the two first and second user devices 300,400 that exchange information. It makes it possible to secure the information transmitted between the two first and second user devices 300,400.

For example, the first user device 300 encrypts a message requesting new session key information using the domain session key information shared in advance with the domain execution agent 200 through the above-mentioned user domain joining procedure, and the domain execution agent 200 To transmit to. The domain execution agent 200 decrypts the received message using the domain session key information shared in advance, recognizes the new domain session key request, and attaches the new domain session key to the first and second user devices 300 and 400, respectively. Transmit information. The first and second user devices 300,400 that received the new session key information are two people who belong to the same user domain by encrypting / decrypting and exchanging the information using the new domain session key information. It is possible to guarantee the security of information transmitted between the first and second user devices 300,400.

At this time, the new domain session key information transmitted to the first and second user devices 300 and 400, respectively, serves as a key value of the symmetric key algorithm for use for security or a mediator (Seed) for deriving the symmetric key value. used.

FIG. 8 is a flowchart showing an information exchange process performed between two first and second user devices 300,400 belonging to the same user domain according to the third embodiment of the present invention. Figure 8 shows the procedure for encrypting and decrypting the information exchanged by two first and second user devices 300,400 belonging to the same user domain in a digital rights management environment using the new session key information. It is a thing.

First, the first user device 300, which joins the user domain and shares the domain session key information with the domain execution agent 200, identifies the second user device 400 to exchange information with the domain execution agent 200, and newly identifies the second user device 400. Request domain session key information (S310). At this time, the new session key request message includes each device identification information of the second user device 400 belonging to the same user domain as the first user device 300.

The requested domain enforcement agent 200 generates new domain session key information for exchanging information between devices and transmits it to the first and second user devices 300,400 (S320). The first and second user devices 300,400 use the new domain session key information received to encrypt / decrypt the information and exchange the information with each other (S330).

As a result, the new domain session key information is a value that only the first and second user devices 300,400 are known, and the other members are not known, so the first user device 300 and the second user device belonging to the same user domain are unknown. The security of the information exchanged with the 400 can be guaranteed.

As described above, according to the third embodiment of the present invention, the domain session key information is shared between the user device and the domain execution agent (DEA) between the user devices belonging to the same user domain. It is possible to form a secure session and maintain communication security in response to a digital rights management (DRM) environment.

Therefore, as the user device 100, various portable communication devices having a communication function defined by OMA DRM version 2.0 such as a mobile phone and a portable personal computer will be described in the first embodiments 1 to 3 above. Functions based on the communication protocol can be easily added by a communication program or the like. In addition, domain subscription processing between user devices and domain enforcement agents (DEA) and information exchange between user devices belonging to the same user domain while maintaining communication security within the domain in a digital rights management (DRM) environment. Since processing is possible, it is possible to improve the reliability of communication services based on OMA DRM version 2.0.

The present invention has been described above, focusing on its preferred embodiments. Those skilled in the art can understand that the present invention can be embodied in a modified form without departing from the essential properties of the present invention. Therefore, the disclosed embodiments must be considered from a descriptive point of view, not from a limiting point of view. The scope of the present invention is expressed in the claims, not in the above description, and all differences within the equivalent scope shall be construed as included in the present invention.

<figref num="1">It is a reference diagram showing the domain joining procedure of OMA DRM version 2.0.</figref><figref num="2">It is a reference diagram showing the process for multiple user devices supporting OMA DRM version 2.0 to use the domain-based rights object (RO).</figref><figref num="3">It is a figure which shows the outline of the user domain joining request / response processing which concerns on 1st Embodiment of this invention.</figref><figref num="4">It is a flowchart which shows the user domain joining process for digital rights management which concerns on 1st Embodiment of this invention.</figref><figref num="5">It is a figure which shows the outline of the information exchange process between a user device and a domain execution agent which concerns on 2nd Embodiment of this invention.</figref><figref num="6">It is a flowchart which shows the information exchange process between the user device and the domain execution agent which concerns on 2nd Embodiment of this invention.</figref><figref num="7">It is a figure which shows the outline of the information exchange process between the user devices belonging to the same user domain which concerns on 3rd Embodiment of this invention.</figref><figref num="8">It is a flowchart which shows the information exchange process between two user devices belonging to the same user domain which concerns on 3rd Embodiment of this invention.</figref><figref num="9">It is a figure which shows an example of the user domain join request message including the function of exchanging domain session key information.</figref><figref num="10">It is a figure which shows an example of the user domain join response message which includes the function of exchanging domain session key information.</figref>

100 ... User device, 200 ... Domain execution agent, 300 ... 1st user device, 400 ... 2nd user device, 900 ... User domain join request message, 902h ... 1st domain Session key information, 1000 ... user domain join response message, 1002j ... second domain session key information.