JP4847301B2 - Content protection system, content protection device, and content protection method - Google Patents

Description

  The present invention relates to content protection technology using sensing information, and in particular, content protection in which a server can determine whether or not to decrypt encrypted content in an information terminal based on position information of the information terminal such as a personal computer. It is about the technology for.

  As a method for protecting the contents of an information terminal such as a personal computer (PC), conventionally, the contents are protected by encrypting the contents or by not storing the contents on the information terminal side as in the thin client method. A method for preventing and protecting content leakage is generally used. When content is encrypted, the threat to protect the content differs depending on when the content is decrypted.

  For example, a method of permitting access to content by user ID / password authentication when logging in to an information terminal (for example, Windows (registered trademark) logon) is a threat of content leakage to a third party when the information terminal is lost. It is used when dealing with A method of distributing a viewing key when viewing content is performed in order to protect the copyright of the content. In addition, a method that allows network connection after checking the status of the information terminal, such as Trusted Network Connect (TNC), is used to deal with the threat of information leakage due to malware on the PC. .

  As security technology using position information, for example, those described in Patent Document 1, Patent Document 2, and the like are known.

  In the file security management program and the file security management device described in Patent Document 1, data is encrypted using location information as an encryption key so that the file cannot be opened except at a designated location. Since the file is encrypted using the location information as a key, it cannot be decrypted without going to that location.

In addition, the security enhancement system described in Patent Document 2 eliminates the risk of “spoofing” by an unauthorized user and aims to strengthen the security function even when using unsafe communication. Use location information to supplement user authentication.
JP 2004-302930 A JP 10-56449 A

  In order to prevent and protect the leakage of content stored in an information terminal, there is a thin client method that does not store content in the information terminal. In this method, since the content is always on the server side, there is no risk of content leakage even if the information terminal is lost. However, since information terminals need to access the server whenever content is used, there is a problem that local operations cannot be performed, a problem that the server load increases in proportion to the number of information terminals, and the load is large. There is a problem that the response decreases when the communication speed is low.

  In addition, in a copyright management system (DRM: Digital Right Management) for digital content such as broadcast and movie content, a relatively simple policy is to decrypt the content only during viewing, and charge and copy restrictions if necessary. The protection of the content by is considered. From the user's point of view, content distribution is restricted, but it is relatively understandable from the viewpoint of copyright.

  However, in order to protect the contents of general information terminals (for example, contents created by employees at work, etc.), if this DRM mechanism is applied as it is, the usability is poor or the management is difficult due to the difference in the contents usage method. It becomes very difficult. In other words, there are cases where the content created for work by employees is desired to be shown to a specific person or a specific group, or may be distributed freely using e-mail. Of course, if it is confidential, it is necessary to prohibit browsing from outside third parties. As described above, there are various content protection policies depending on the type of content, the owner, and the like, and the current situation is that it is not possible to simply use the DRM mechanism applied to broadcast content.

  When content held by an information terminal is protected based on only an ID or a password, it is difficult to realize high security. If the location information of the information terminal can be used for content protection, a thicker policy for content protection than before can be adopted without imposing a heavy burden on the user.

  For example, Patent Document 1 or Patent Document 2 discloses a technique for using position information for security. In the technique described in Patent Document 1, a key derived from position information of a decodable area is used. The content is encrypted by using it, and the content can be decrypted only within the decryptable area. Therefore, the content once encrypted with the key including the location information cannot be used unless it goes to the location. There is a problem. That is, it is not possible to determine a policy as to where the content can be decrypted without depending on the content.

  In the technique described in Patent Document 2, user authentication is complemented by terminal location information, but protection of content itself is not considered.

  The present invention solves the above-mentioned problems and protects leakage of content stored in an information terminal by utilizing sensing information, thereby making it easy for users to use and making content protection policies dependent on content. The goal is to be able to make decisions without any problems.

  The present invention uses sensing information in order to solve the above-described problems and prevent information leakage without impairing user operability. As sensing information, position information is used. The content in the information terminal is encrypted on a file basis. Alternatively, the entire storage device may be encrypted.

  The management server holds a key necessary for decrypting the encrypted content in the information terminal. In addition, the management server manages the decryption permission / prohibition condition for each information terminal based on various policies based on the position information such as where the information terminal exists and whether it is moving.

  When the information terminal decrypts and refers to the encrypted content, it receives information obtained by encrypting the identification information and the position information from a removable device such as a USB, and sends it to the management server to make a key acquisition request. . The detachable device incorporates a position sensor and encryption processing means, and in response to a request from the information terminal, the position information detected by the position sensor and the identification information are encrypted with a built-in key and notified to the information terminal. The identification information is the ID of the user or information terminal, and is stored in the storage means of the removable device or input from the information terminal.

  When there is a key acquisition request from the information terminal, the management server decrypts the encrypted information received from the information terminal, and checks whether the pre-registered decryption permission condition is satisfied from the position information and the identification information. When the decryption permission / inhibition condition is satisfied, a key necessary for decrypting the encrypted content in the information terminal is transmitted to the information terminal.

  As a result, the key for decrypting the encrypted content can be acquired from the management server only when the information terminal is at a specific position, and the encrypted content can be decrypted and referenced. The user of this system can use the information terminal in the same manner as usual if an area where the information terminal can be used is registered in the management server in advance. Even if the information terminal is stolen, the content is not decrypted because the positions do not match. If it is desired to operate the information terminal during movement, the movement section is registered in advance in the management server as a decodable area. Even if the information terminal is misplaced in the moving section, the content cannot be handled at the moment when the information terminal leaves the area.

  In this way, content can be protected simply by specifying the user's actions and the situation of the person accessing the content (particularly location information) in advance, and how the location information is treated as a decryption condition. You can freely decide on a policy.

  According to the present invention, leakage of contents stored in an information terminal can be prevented and effectively protected using sensing information without impairing user operability.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration example of the present invention. In FIG. 1, an information terminal 10 is a device such as a personal computer (PC), and is connected via a network 40 to a management server 30 that manages a key for decrypting content. A removable device 20 is connected to the information terminal 10 through an interface such as a USB, and the removable device 20 can be inserted into and removed from the information terminal 10.

  The information terminal 10 includes an encrypted content storage unit 13 that stores encrypted content that is a file of encrypted video, image, sound, program, and other data. In addition, the information terminal 10 obtains encryption information from the communication control unit 11 such as a network adapter for performing communication via the network 40 and the detachable device 20 and stores the encryption information stored in the encrypted content storage unit 13. The information terminal 10 sends the encrypted information acquisition unit 12 that requests the management server 30 for a decryption key for the encrypted content or a decryption key for decrypting the decrypted key, and the encrypted content stored in the encrypted content storage unit 13. A file system 14 for use by an operating program. The file system 14 includes a decryption processing unit 15 that decrypts the encrypted content stored in the encrypted content storage unit 13 using the decryption key received from the management server 30.

  The detachable device 20 includes an identification information input unit 21 for inputting identification information such as a PIN from the information terminal 10, and a position detection unit using a GPS (Global Positioning System) or a wireless tag having a function of detecting a specific position. 22, the encryption key storage unit 23 that stores a preset encryption key, the identification information input by the identification information input unit 21, and the position information detected by the position detection unit 22 are stored in the encryption key storage unit 23. An encryption processing unit 24 that performs encryption using an encryption key is provided. Further, a clock 25 may be provided in the detachable device 20 so that the current time obtained from the clock 25 is encrypted by the encryption processing unit 24. The information encrypted by the encryption processing unit 24 is transferred to the encrypted information acquisition unit 12 of the information terminal 10 via the device interface.

  In this example, the identification information input unit 21 inputs the identification information from the information terminal 10, but instead of inputting the identification information from the information terminal 10, the preset identification information is stored in the removable device 20. It is also possible to implement the present invention in which the tamper area is held and used. The tamper resistant area is an area where only the microprocessor in the removable device 20 can access information, and the information cannot be directly referred to or updated from the outside.

  The management server 30 uses the encryption key stored in the encryption key storage unit 23 to store the encryption information sent from the communication control unit 31 configured by a network adapter and the like and the encryption information acquisition unit 12 of the information terminal 10. The decryption processing unit 32 that decrypts with the decryption key corresponding to, and the position information and the identification information decrypted by the decryption processing unit 32 or the time for transmitting the key for decrypting the encrypted content to the information terminal 10 A policy determining unit 33 that determines whether or not to perform the determination, and a condition for determining whether or not the decryption key can be transmitted, that is, whether or not the encrypted content can be decrypted (hereinafter, this is referred to as a decryption permission / prohibition condition). When the decryption permission / rejection condition storage unit 34 stores the key information for the information terminal 10 to decrypt the encrypted content, and the policy determination unit 33 determines that decryption is possible And a key management unit 35 to send the key information to the information terminal 10.

  FIG. 2 shows an example of encrypted content stored in the encrypted content storage unit 13 of the information terminal 10.

  In this embodiment, the format of the encrypted file stored in the information terminal 10 is as shown in FIG. Each file is encrypted with a different encryption key. In this example, the file A (130A) is encrypted with the key A, and the file B (130B) is encrypted with the key B. Furthermore, each key is encrypted and stored as meta information 131A, 131B of each file A, B. In order to decrypt the file A, first, the key A encrypted with the public key Pub in the meta information 131A is decrypted with the private key (Pri) paired with the public key Pub, and the decrypted key A is used. The encrypted file A is decrypted. The secret key (Pri) paired with this public key Pub is acquired from the management server 30 as will be described in detail later.

  FIG. 3 shows an example of how the encrypted content is used in the information terminal 10. In this figure, the module configuration in the information terminal 10 and the flow until the mailer 16 browses the decrypted file A are shown. First, the mailer 16 requests the file system 14 to acquire the file A in order to view the file A (P1). The file system 14 knows that the file is decrypted from the meta information of the file. For this purpose, the encrypted key A stored in the meta information is extracted, and the control application 17 is requested to decrypt the key A (P2). The control application 17 decrypts the key A using the secret key Pri acquired from the management server 30, and returns it to the file system 14 (P3). The file system 14 reads the encrypted file A from the encrypted content storage unit 13 (P4), decrypts the read file A (P5), and passes it to the mailer 16 (P6).

  FIG. 4 shows an example of the processing sequence of the entire system. Hereinafter, the sequence of processing in which the information terminal 10 acquires the decryption key (secret key Pri) from the management server 30 will be described according to (a) to (m) shown in FIG. The detachable device 20 includes a microprocessor (MPU) 200 for realizing the identification information input unit 21 and the encryption processing unit 24, a tamper-resistant region 230 that is a storage unit corresponding to the encryption key storage unit 23, a position A position sensor 220 such as a GPS corresponding to the detection unit 22 is provided.

  The tamper resistant area 230 of the detachable device 20 includes a PIN (Personal Identification Number) for authenticating the user, identification information of the user who uses the encrypted content (herein referred to as a personal ID), management The same secret key as the secret key held by the server 30 is stored in advance. In this example, it is assumed that the management server 30 and the detachable device 20 hold the same shared secret key. However, instead of the shared secret key, for example, the management server 30 holds the secret key, and the detachable device 20 It is possible to implement a method in which a public key paired with the secret key is held.

  (A) The information terminal 10 inputs a PIN for personal authentication from the user, specifies the PIN to the detachable device 20 and requests encryption information.

  (B) The microprocessor 200 collates the designated PIN with the PIN stored in the tamper resistant area 230, and notifies the information terminal 10 of an error if they do not match. If they match, the process proceeds to the following encryption process.

  (C) The microprocessor 200 acquires the personal ID and the shared secret key from the tamper resistant area 230.

  (D) Next, the microprocessor 200 acquires the current position information from the position sensor 220.

  (E) The microprocessor 200 encrypts the position information and the personal ID with the secret key acquired from the tamper resistant area 230 and notifies the information terminal 10 of it. Also, the information terminal 10 is notified of an ID uniquely assigned to the detachable device 20 (hereinafter referred to as USB-ID).

  (F) The information terminal 10 transmits the USB-ID received from the detachable device 20, the encrypted position information, and the personal ID to the management server 30, and requests a decryption key.

  (G) The management server 30 decrypts the position information received from the information terminal 10 and the encrypted information of the personal ID with a shared secret key registered in advance corresponding to the designated USB-ID. Based on the position information and personal ID as a result of the decryption, the decryption permission condition is determined according to the decryption permission determination policy set in the management server 30 in advance, and the decryption enabled state is verified.

  (H) When decryption is possible, the management server 30 transmits a key (secret key Pri) for decrypting the content decryption key to the information terminal 10.

  (I) to (k) The detachable device 20 periodically acquires the position information from the position sensor 220, encrypts it and the personal ID with a shared secret key, and the information terminal 10 transmits the encrypted information and the USB-ID. Are repeatedly transmitted to the management server 30.

  (L) to (m) The management server 30 repeats the process of decrypting the encryption information sent periodically with the shared secret key and verifying the decryption permission / inhibition condition. If “impossible”, the decryption prohibition instruction is transmitted to the information terminal 10. In the information terminal 10, subsequent decryption of the encrypted content is prohibited by reception of the decryption prohibit command.

  In the above example, the detachable device 20 collates the input PIN with the internal PIN, and encrypts the personal ID stored therein together with the location information. It is possible to use the personal ID and encrypt it together with the location information. The same applies to other embodiments described later.

  FIG. 5 shows an example of a processing flow in the management server 30. In the following, a flow of processing when the policy determination unit 33 of the management server 30 determines whether or not decoding is possible according to the policy of the decoding permission / prohibition condition that decoding is possible when the information terminal 10 has not moved beyond a specific range will be described.

  The management server 30 waits for reception of a key request from the information terminal 10 (step S10), and receives encrypted information requesting a key and a USB-ID from the information terminal 10 (step S10). Step S11). The encrypted information received from the information terminal 10 is decrypted with a shared secret key registered in advance for each USB-ID (step S12). Next, it is determined whether or not there is already accumulated position information (step S13). If the position information is received for the first time, there is no accumulated position information. After accumulating, the process returns to step S10 and waits for reception from the next information terminal 10.

  When the position information is received twice or more from the information terminal 10, since the accumulated position information exists, the accumulated position information is compared with the currently received position information to calculate the movement distance (step S15). ). If the moving distance is not greater than the specific range set in advance in the management server 30, it is determined that decryption is possible, and the process proceeds to step S17, where a secret key for decrypting the decryption key of the encrypted content is transmitted to the information terminal 10. . If the moving distance is equal to or greater than the specific range, it is determined that decryption is impossible, and the process proceeds to step S18 to transmit a content decryption prohibition command to the information terminal 10. In the information terminal 10, the control application 17 shown in FIG. 3 rejects subsequent key decryption requests of the file system 14 by receiving the content decryption prohibition instruction.

  In the present embodiment, the location information sensed by the location detection unit 22 in the detachable device 20 connected to the information terminal 10 is periodically transmitted to the management server 30, thereby prohibiting browsing of information during movement. be able to.

  Further, by encrypting the position information sensed by the position detection unit 22 with the encryption processing unit 24, it is possible to prevent the position information from being spoofed together with the identification information. Furthermore, by providing the detachable device 20 with this function and separating it from the information terminal 10, the encrypted content cannot be decrypted if the detachable device 20 and the information terminal 10 are not present. Protection is realized.

  Next, an embodiment will be described in which whether or not decoding is possible is determined by a policy using time information in addition to position information. FIG. 6 shows an example of the processing sequence of the entire system when time is used as the decision policy for decryption. Hereinafter, the sequence of processing in which the information terminal 10 acquires the decryption key (secret key Pri) from the management server 30 will be described according to (a) to (j) shown in FIG. The detachable device 20 includes a microprocessor (MPU) 200 for realizing the identification information input unit 21 and the encryption processing unit 24, a tamper-resistant region 230 that is a storage unit corresponding to the encryption key storage unit 23, a position In addition to a position sensor 220 such as a GPS corresponding to the detection unit 22, a clock 25 is provided.

  (A) The information terminal 10 inputs a personal identification number (PIN) for personal authentication from the user, specifies the PIN to the detachable device 20, and requests encryption information.

  (B) The microprocessor 200 collates the designated PIN with the PIN stored in the tamper resistant area 230, and notifies the information terminal 10 of an error if they do not match. If they match, the process proceeds to the following encryption process.

  (C) The microprocessor 200 acquires the personal ID and the shared secret key from the tamper resistant area 230.

  (D) Next, the microprocessor 200 acquires the current position information from the position sensor 220.

  (E) Further, the microprocessor 200 acquires the current time from the clock 25.

  (F) The microprocessor 200 encrypts the position information, the time, and the personal ID with the secret key acquired from the tamper resistant area 230 and notifies the information terminal 10 together with the USB-ID.

  (G) The information terminal 10 transmits the USB-ID, the encrypted location information, the time, and the personal ID from the detachable device 20 to the management server 30 and requests a decryption key.

  (H) The management server 30 decrypts the position information, time, and personal ID encrypted information received from the information terminal 10 with the shared secret key corresponding to the designated USB-ID. Based on the position information, the time, and the personal ID as a result of the decryption, the decryption permission condition is determined according to the decryption permission determination policy set in advance in the management server 30, and the decryption permission state is verified.

  (I) When decryption is possible, the management server 30 transmits a key (secret key Pri) for decrypting the content decryption key to the information terminal 10.

  (J) to (k) If the time included in the received encrypted information has passed a predetermined time or more from the current time according to a preset policy for determining whether or not to allow decryption, it is determined that decryption is impossible. , A decryption prohibition instruction is transmitted to the information terminal 10. In the information terminal 10, subsequent decryption of the encrypted content is prohibited by reception of the decryption prohibit command.

  FIG. 7 shows an example of a processing flow when the time in the management server 30 is used. In the following, the flow of processing when the policy determination unit 33 of the management server 30 determines whether or not decoding is possible according to the policy of the decoding permission / prohibition condition that decoding is possible only when the time sent from the information terminal 10 is within a certain time. explain.

  The management server 30 waits for reception of a key request from the information terminal 10 (step S20). If encrypted information requesting a key is sent from the information terminal 10, it receives the encrypted information ( Step S21). The encrypted information received from the information terminal 10 is decrypted with a preset shared secret key corresponding to the USB-ID received from the information terminal 10 (step S22). Next, the time included in the decoded information is stored (step S23).

  In accordance with the decoding policy for determining whether or not to decode the position information set in advance in the management server 30, a condition for determining whether or not to decode the position information is determined (step S24). If decoding is impossible, the process proceeds to step S29. If the position information is decodable, then the time decipherability condition is determined (step S25). If the received time has already passed a certain time, it is determined that the decipherment is impossible and step S29 is performed. Proceed to

  When the decryption permission / prohibition condition of the position information and time is decryptable, a secret key for decrypting the decryption key of the encrypted content is transmitted to the information terminal 10 (step S26). Thereafter, it waits for a certain time to elapse (step S27), and if the certain time elapses, it transmits a decryption prohibition instruction to the information terminal 10 (step S28). It is also possible to adopt a configuration in which steps S27 and S28 are omitted, and processing is performed according to a policy that does not transmit a decryption prohibition instruction to the information terminal 10.

  In step S24 or S25, when the position information or the time does not satisfy the decryption permission / prohibition condition, information indicating the reason why decryption is impossible is transmitted to the information terminal 10 in step S29, and the decryption of the encrypted content is prohibited.

  According to the present embodiment, since the encrypted time information is transmitted in addition to the transmission of the encrypted location information from the information terminal 10, the management server 30 side compares the actual time and transmits the encrypted time information. The danger of reusing packets can be prevented. That is, even when a decryption request packet sent from the information terminal 10 to the management server 30 in the past is copied as it is and used by another information processing apparatus, the time is old and a certain time has passed. Is not allowed.

  Next, in this system, when all the information terminals 10 in the predetermined group are connected to the management server 30, or the number of connections of the information terminals 10 in the predetermined group has reached a certain number or more. An embodiment in which the policy determining unit 33 permits distribution of the content decryption key will be described. The information terminal ID described in the following example is identification information for uniquely identifying the information terminal 10, and may be the same identification information as the personal ID shown in FIG.

  FIG. 8 shows an example of information managed by the management server 30. In the present embodiment, the management server 30 holds a state table 341 that holds group information of the information terminals 10, connection status information of each information terminal 10, and position information in the decryption permission / inhibition condition storage unit 34. Further, group position restriction information 342 for each group that is arbitrarily set in advance is held.

  In this example, in the state table 341, the information terminals 10 having information terminal IDs 1001, 1011, 1015, and 1102 are defined as one group (group ID = G1). As the group location restriction information 342, in this example, in order for the information terminal 10 belonging to the group G1 to receive the distribution of the decryption key, there are certain predetermined locations such as in Tokyo, Yokohama, and XX factory. A position range condition that the position must be within a specific range is registered, and in order for the information terminal 10 belonging to the group G2 to receive the distribution of the decryption key, a distance such as within a radius of 100 m is required. A range condition is registered. Also, whether or not the decryption permission condition is satisfied only when all the information terminals 10 in the group are connected, or a certain number of information terminals 10 or more in the group are connected, and this is the position range condition and the distance range. If the above condition is satisfied, information such as whether the decryption availability condition is satisfied can be set in advance.

  The key management table 351 managed by the key management unit 35 stores a secret key corresponding to the USB-ID and each information terminal ID (or personal ID), but this is the same in other embodiments. It is. The USB-ID is an ID used for specifying a secret key for decrypting the encrypted information sent from the information terminal 10 in the management server 30, and the secret key can be specified by other methods. If so, the USB-ID unique to the detachable device 20 is not necessarily used.

  In the status table 341 shown in FIG. 8, when the information terminal 10 is connected to the management server 30, “◯” is displayed as the connection status of the information terminal 10, and the position information is also stored. It has become. This position information may be coordinate values such as longitude / latitude, or information obtained by converting coordinate values into district names or area names. When the information terminal 10 is not connected to the management server 30, the connection status of the information terminal 10 is “x”.

  FIG. 9 shows an example of a processing flow in the management server 30 according to this embodiment. In the following, when the policy determination unit 33 of the management server 30 receives a key acquisition request from the information terminal 10, the status table 341 is referenced to check whether all the members of the group are connected, and all the members are connected. However, an example will be described in which processing is performed in accordance with a decryption permission / prohibition condition policy in which a decryption key is sent only when it is within a predetermined position range.

  Waiting for reception of a key request from the information terminal 10 (step S30), and if encryption information requesting a key is sent from the information terminal 10 (for example, information terminal ID = 1001), encryption of the key acquisition request Information is received (step S31). The encrypted information received from the information terminal 10 is decrypted with a preset shared secret key corresponding to the USB-ID received from the information terminal 10 (step S32).

  Next, with reference to the status table 341, it is confirmed whether all the groups to which the information terminal 10 that issued the key acquisition request belongs are in a connected state (step S33). If there is a member of a group that is not yet connected, the process proceeds to step S34. In step S34, in the status table 341, the connection status of the information terminal 10 that issued the key acquisition request is set to the connected status, and the location information is written. Since there are no group members yet in the information terminal 10, the key Notify that it cannot be sent. Thereafter, the process returns to step S30 and waits for reception from another information terminal 10.

  If it is confirmed in step S33 that all the groups are in a connected state, the position information in the state table 341 is then referenced to confirm whether all members are in the permitted position (step S35). If there is a member who is not in the permitted position, a notification is sent that the key cannot be transmitted because the group member is not yet in the permitted position (step S36). Thereafter, the process returns to step S30, and the other information terminal 10 Wait for reception from.

  If it is confirmed in step S35 that all members are in the permitted position, a key for decrypting the encrypted decryption key of the encrypted content is distributed to all members of the group (step S37). .

  As described above, the position information that can be permitted by the group or the distance limitation of the information terminal 10 is added to the state table 341, and the content is decrypted only when each information terminal 10 is connected and is in the vicinity. The key for this is distributed to the information terminal 10. As a result, it is possible to realize that each information terminal 10 is connected to the management server 30 and that the content can be decrypted only when it is in the vicinity.

  As described above, since the encrypted content can be decrypted only when the specific group gathers at a specific position and connects to the management server 30, the condition for decrypting the content can be tightened, and the safety can be improved. Can be increased.

  The processes executed by the information terminal 10 and the management server 30 can be realized by a computer and a software program, and the program can be provided by being recorded on a computer-readable recording medium. Is also possible.

It is a figure which shows the system configuration example of this invention. It is a figure which shows the example of the encryption content memorize | stored in an encryption content memory | storage part. It is a figure which shows the example of the utilization form of the encryption content in an information terminal. It is a figure which shows the example of the process sequence of the whole system. It is a figure which shows an example of the processing flow in a management server. It is a figure which shows the example of the other process sequence of the whole system. It is a figure which shows an example of the processing flow in a management server. It is a figure which shows the example of the information which a management server manages. It is a figure which shows an example of the processing flow in a management server.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Information terminal 11 Communication control part 12 Encrypted information acquisition part 13 Encrypted content storage part 14 File system 15 Decryption processing part 20 Detachable device 21 Identification information input part 22 Position detection part 23 Encryption key storage part 24 Encryption processing part 25 Clock DESCRIPTION OF SYMBOLS 30 Management server 31 Communication control part 32 Decryption process part 33 Policy determination part 34 Decryption availability condition memory | storage part 35 Key management part 40 Network

Claims (7)

A content protection system comprising a management server for managing a decryption key, an information terminal connected to the management server via a network, and a device connected to the information terminal,
The device is
Means for storing identification information previously registered or inputted from the information terminal;
Position detecting means for detecting current position information;
An encryption processing means for encrypting the identification information and the position information detected by the position detection means in advance with an encryption key stored in advance in response to a request from the information terminal, and notifying the information terminal;
The information terminal is
Means for storing encrypted content;
Means for obtaining encrypted identification information and location information from the device;
Means for transmitting the encrypted identification information and location information to the management server;
Means for receiving a decryption key from the management server;
Decryption processing means for decrypting the encrypted content or the encrypted decryption key for decrypting the encrypted content using the received decryption key,
The management server
Means for receiving encrypted identification information and location information from the information terminal;
Decryption processing means for decrypting the encrypted identification information and position information with a decryption key corresponding to an encryption key held by the device;
Policy determining means for determining a decoding permission / prohibition condition using the position information of the information terminal registered in advance based on the decoded identification information and the position information,
When the policy determining means determines that decryption is possible, a decryption key for decrypting the encrypted content held by the information terminal, or an encrypted decryption for decrypting the encrypted content A content protection system comprising: means for transmitting a decryption key for decrypting the key to the information terminal. A content protection system comprising a management server for managing a decryption key, an information terminal connected to the management server via a network, and a device connected to the information terminal,
The device is
Means for storing identification information previously registered or inputted from the information terminal;
Position detecting means for detecting current position information;
A clock that measures time,
Cryptographic processing means for encrypting the identification information, the position information detected by the position detecting means, and the time acquired from the timepiece with an encryption key stored in advance, and notifying the information terminal in response to a request from the information terminal And
The information terminal is
Means for storing encrypted content;
Means for obtaining encrypted identification information, position information and time from the device;
Means for transmitting the encrypted identification information, location information and time to the management server;
Means for receiving a decryption key from the management server;
Decryption processing means for decrypting the encrypted content or the encrypted decryption key for decrypting the encrypted content using the received decryption key,
The management server
Means for receiving encrypted identification information, position information and time from the information terminal;
Decryption processing means for decrypting the encrypted identification information, position information, and time with a decryption key corresponding to an encryption key held by the device;
Policy determining means for determining whether or not decoding is possible based on the position information and time of the information terminal registered in advance based on the decoded identification information, position information and time,
When the policy determining means determines that decryption is possible, a decryption key for decrypting the encrypted content held by the information terminal, or an encrypted decryption for decrypting the encrypted content A content protection system comprising: means for transmitting a decryption key for decrypting the key to the information terminal. The information terminal is
Means for periodically transmitting encrypted information including encrypted location information acquired from the device to the management server;
The management server
Based on the result of decrypting the encrypted information transmitted periodically, the decryption permission condition is determined, and when the decryption enabled state is changed to the decryption disabled state, the decryption key to the information terminal is 3. The content protection system according to claim 1, wherein instruction information for stopping transmission or prohibiting decryption is transmitted. The decryption permission condition held by the management server is as follows:
Conditions for enabling decoding when the information terminal is within a certain range, or a plurality of predetermined information terminals or a predetermined number of information terminals or more are connected to the management server, and their information The content protection system according to claim 1, wherein the content protection system includes a condition that enables decryption when the terminal is in a specific position. A device that is detachably connected to the information terminal used in the content protection system according to claim 1, claim 2, claim 3, or claim 4 via a predetermined interface,
Means for storing identification information previously registered or inputted from the information terminal;
Position detecting means for detecting current position information;
And at least a cryptographic processing means for encrypting the identification information and the position information detected by the position detecting means with an encryption key stored in advance in advance in response to a request from the information terminal and notifying the information terminal. Feature content protection device. A content protection method in a content protection system comprising a management server for managing a decryption key, an information terminal connected to the management server via a network, and a device connected to the information terminal,
The device is
Storing the identification information registered in advance or input from the information terminal;
A process of detecting current position information by means of position detection;
An encryption process for encrypting the identification information and the position information detected by the position detection means in advance with an encryption key stored in advance in accordance with a request from the information terminal, and notifying the information terminal;
The information terminal is
Storing encrypted content; and
Obtaining encrypted identification information and location information from the device;
Transmitting the encrypted identification information and location information to the management server;
Receiving a decryption key from the management server;
Decrypting the encrypted content or the encrypted decryption key for decrypting the encrypted content using the received decryption key, and
The management server is
Receiving encrypted identification information and location information from the information terminal;
A decryption process of decrypting the encrypted identification information and position information with a decryption key corresponding to an encryption key held by the device;
A policy determination process for determining whether or not decoding is possible based on the decrypted identification information and location information, and determining whether or not decoding is possible using the location information of the information terminal registered in advance;
When the policy determination process determines that decryption is possible, the decryption key for decrypting the encrypted content held by the information terminal, or the encrypted decryption for decrypting the encrypted content A content protection method comprising: transmitting a decryption key for decrypting the key to the information terminal. A content protection method in a content protection system comprising a management server for managing a decryption key, an information terminal connected to the management server via a network, and a device connected to the information terminal,
The device is
Storing the identification information registered in advance or input from the information terminal;
A position detection process in which current position information is detected by the position detection means;
The process of measuring time with a clock,
In response to a request from the information terminal, an encryption process for encrypting the identification information, the position information detected by the position detecting means, and the time acquired from the clock with an encryption key stored in advance, and notifying the information terminal And
The information terminal is
Storing encrypted content; and
Obtaining encrypted identification information, location information and time from the device;
Transmitting the encrypted identification information, location information, and time to the management server;
Receiving a decryption key from the management server;
Decrypting the encrypted content or the encrypted decryption key for decrypting the encrypted content using the received decryption key, and
The management server is
Receiving encrypted identification information, location information, and time from the information terminal;
A decryption process of decrypting the encrypted identification information, position information, and time with a decryption key corresponding to an encryption key held by the device;
A policy determination process for determining whether or not decoding can be performed by determining a decoding permission condition using the position information and time of the information terminal registered in advance based on the decoded identification information, position information and time;
When the policy determination process determines that decryption is possible, the decryption key for decrypting the encrypted content held by the information terminal, or the encrypted decryption for decrypting the encrypted content A content protection method comprising: transmitting a decryption key for decrypting the key to the information terminal.

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