JP2007180659A - Wireless communication method, information distribution apparatus and wireless communication terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide improve the security while suppressing degradation in the operating efficiency of wireless resources when encrypted information is distributed in a wireless communication system for performing a multicast or broadcast distribution service. <P>SOLUTION: A wireless communication method for transmitting distribution information from an information distribution apparatus to a wireless communication terminal includes: a step conducted by the information distribution apparatus side, of encrypting the distribution information; a step conducted by the information distribution apparatus side, of detecting an encrypted information distribution channel for distributing the encrypted information used for the encryption to a particular wireless communication terminal; a step conducted by the information distribution apparatus side, of transmitting the encrypted information by using the encrypted information distribution channel: a step conducted by the particular wireless communication terminal, of receiving the encrypted information through the encrypted information distribution channel; and a step conducted by the particular wireless communication terminal, of decrypting the encrypted distribution information on the basis of the encrypted information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless communication method, an information distribution apparatus, and a wireless communication terminal.

  As one of distribution services for content information such as video and music on the Internet, a multicast distribution service that distributes the same content information to a plurality of service subscriber terminals is known. In a multicast distribution service in a wireless communication system, the base station uses a common communication channel called a multicast channel, and content information that is the same as that of a service subscriber user terminal (for example, a wireless communication terminal such as a mobile phone) existing in the communication area. Therefore, there is an advantage that the use efficiency of radio resources is high compared to a service that performs one-to-one communication between a base station and a terminal. Similarly, a service that distributes content information to an unspecified number of terminals that exist in a communication area using a broadcast channel that is a common communication channel is called a broadcast distribution service.

As described above, since a common communication channel is used in the multicast distribution service, a situation may occur in which content information is received even by a user who has not subscribed to the service. In order to solve this problem, for example, in Japanese Patent Laid-Open No. 2004-032711, when content information is distributed through a common communication channel, the content information is encrypted, and only the service subscriber user (that is, the charging user) is encrypted. Disclosed is a technique for distributing service information so that an unsubscribed user cannot decrypt content information by distributing encrypted information for decryption.
JP 2004-032711 A

 However, since the same encrypted content information is distributed in the conventional multicast distribution service, if a malicious unsubscribed user obtains the encrypted information by any method, the content information will be decrypted. Safety issues remain. In order to solve this, there are a method of increasing the update frequency of the encryption information and a method of providing different encryption information for each charging user. When these methods are adopted, the base station and the terminal are The number of communications increases, the use efficiency of radio resources decreases, and the advantage of the multicast distribution service is impaired.

  The present invention has been made in view of the above-described circumstances, and in a wireless communication system that performs a multicast or broadcast distribution service, while suppressing a decrease in use efficiency of wireless resources when distributing encrypted information, It aims to improve.

 In order to achieve the above object, the present invention provides a wireless communication method for transmitting distribution information from an information distribution device to a wireless communication terminal as a first solution means related to a wireless communication method, wherein the information distribution device side A step of encrypting the distribution information, a step of detecting a channel for distributing the encrypted information for distributing the encrypted information used for the encryption to a specific wireless communication terminal, and the distribution of the encrypted information Transmitting encrypted information using a dedicated channel; receiving encrypted information on the encrypted information distribution channel at the specific wireless communication terminal; and encrypting based on the encrypted information And a step of decrypting the distributed distribution information.

 In the present invention, as the second solving means related to the wireless communication method, in the first solving means, the information distribution apparatus side makes the request based on the information distribution request from the wireless communication terminal. Determining whether or not the wireless communication terminal is a specific wireless communication terminal, and, if the wireless communication terminal is a specific wireless communication terminal, use for permitting use of the encrypted information distribution channel Transmitting permission information to the specific wireless communication terminal; detecting the encrypted information distribution channel when the specific wireless communication terminal receives the use permission information; and Receiving encrypted information on a channel for distributing encrypted information.

Further, in the present invention, as a third solving means relating to a wireless communication method, in the first or second solving means, the information distribution apparatus side updates the encrypted information to change in a certain period; Detecting a new encrypted information distribution channel for distributing the updated encrypted information to a specific wireless communication terminal; and updating the updated information from the information distribution apparatus to the specific wireless communication terminal. Delivering encrypted information in the detected encrypted information delivery channel; and receiving the updated encrypted information in the encrypted information delivery channel by the specific wireless communication terminal; Further comprising the step of decrypting the encrypted distribution information based on the updated encrypted information.

 According to the present invention, as the fourth solving means relating to the wireless communication method, in the second or third solving means, a predetermined expiration date is set in the use permission information, and the expiration date has passed. In this case, the specific wireless communication terminal does not detect the encrypted information distribution channel.

 Further, in the present invention, as a fifth solving means relating to a wireless communication method, in any one of the first to fourth solving means, the information distribution device is configured to transmit the encrypted information distribution channel according to a communication status. Is detected.

 On the other hand, in the present invention, as a first solving means related to the information distribution apparatus, an information distribution apparatus that transmits distribution information to a wireless communication terminal, the encryption means for encrypting the distribution information, and the encryption Encrypted information distribution channel detecting means for detecting a channel for distributing encrypted information for distributing encrypted information to be used to a specific wireless communication terminal, and encrypted information using the channel for distributing encrypted information The communication control means for transmitting is provided.

 Furthermore, in the present invention, as a first solving means relating to a wireless communication terminal, a wireless communication terminal capable of receiving distribution information from an information distribution device, the distribution information distributed from the information distribution device, A terminal-side communication control means for receiving encrypted information used for encryption in a channel for distributing encrypted information; and a decrypting means for decrypting the encrypted distribution information based on the encrypted information. , Is adopted.

  ADVANTAGE OF THE INVENTION According to this invention, in the radio | wireless communications system which performs a multicast or broadcast delivery service, it is possible to improve safety | security, suppressing the fall of the use efficiency of the radio | wireless resource at the time of delivering encryption information.

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a wireless communication system including a base station B (information distribution apparatus) for performing a multicast distribution service according to an embodiment of the present invention and a wireless communication terminal T (for example, a mobile phone) receiving the service. FIG.

  As shown in this figure, the base station B includes a wireless communication unit 1, a user authentication unit 2, an authentication information database 3, a viewing key generation unit 4, a continuous use key generation unit 5, a storage unit 6, an encryption unit 7, It comprises a content information storage unit 8, a viewing key distribution channel selection unit 9 (encrypted information distribution channel detection means), and a communication control unit 10. The wireless communication terminal T includes a wireless communication unit 20, a key input unit 21, a storage unit 22, a decryption unit 23, an audio output unit 24, a display unit 25, a viewing key distribution channel detection unit 26, and a communication control unit 27. It is configured.

In the base station B, the wireless communication unit 1 performs wireless communication with the wireless communication terminal T using a multicarrier communication system under the control of the communication control unit 10. The user authentication unit 2
Individual information and subscriber information of the wireless communication terminal T input from the communication control unit 10 (these individual information and subscriber information are used when making a connection request {information distribution request} to the multicast distribution service to the base station B. Wireless communication terminal T) and wireless communication based on a plurality of individual information and subscriber information stored in authentication information database 3. An authentication process is performed to determine whether the user having the terminal T is a subscriber of the multicast distribution service, and the authentication process result is output to the communication control unit 10. The authentication information database 3 stores in advance individual information and subscriber information of a wireless communication terminal for each of a plurality of users, and the individual authentication information and subscriber information are stored in the user authentication unit in response to a request from the user authentication unit 2. Output to 2.

  In response to a request from the communication control unit 10, the viewing key generation unit 4 uses a viewing key (encrypted information) used for encryption and decryption of content information (distribution information) and an expiration date of the viewing key. And the viewing time limit information and the viewing time limit information are output to the storage unit 6 and the communication control unit 10, and the viewing key is output to the encryption unit 7. In response to a request from the communication control unit 10, the continuous use key generation unit 5 continues use key (use permission information) indicating the right to access the viewing key distribution channel and the continuous use key indicating the expiration date of the continuous use key. The time limit information is generated, and the continuous use key and the continuous use time limit information are output to the storage unit 6 and the communication control unit 10. The storage unit 6 stores the viewing key, the viewing time limit information, the continuous use key, and the continuous use time limit information, and information (content distribution channel information) indicating a control program and a content distribution channel used in the communication control unit 10, Various other data are stored.

The encryption unit 7 encrypts the content information stored in the content information storage unit 8 using the viewing key input from the viewing key generation unit 4 in response to a request from the communication control unit 10. The encrypted content information is output to the communication control unit 10. The content information storage unit 8 stores content information such as video and music for multicast distribution service from a server (not shown) that distributes the content information, and the content information according to the request of the encryption unit 7 Is output to the encryption unit 7.

  The viewing key distribution channel selection unit 9 acquires the viewing key and the continuous use key from the storage unit 6 in response to a request from the communication control unit 10, and based on the viewing key distribution channel selection algorithm using these as parameters. Then, the distribution channel of the viewing key is determined (detected), and the viewing key distribution channel information is output to the communication control unit 10. This viewing key distribution channel is a communication channel common to wireless communication terminals existing in the communication area of the base station B (that is, a multicast channel). Note that the content distribution channel used for distributing the content information is also a multicast channel, but the frequency band is different from the viewing key distribution channel.

 The communication control unit 10 controls the overall operation of the base station B based on the control program stored in the storage unit 6, the communication state of the wireless communication unit 1, and the like. In addition, as a characteristic control process based on the control program, the communication control unit 10 is configured to view and listen when the user of the wireless communication terminal T is a subscriber of the multicast distribution service based on the authentication processing result by the user authentication unit 2. The key generation unit 4 is requested to generate the viewing key and the viewing time limit information, and the continuous use key generation unit 5 is requested to generate the continuous use key and the continuous use time limit information. The wireless communication unit 1 is controlled to transmit the content distribution channel information stored in the wireless communication terminal T to the wireless communication terminal T using the registration channel.

 On the other hand, when the user is a non-service subscriber, the communication control unit 10 requests the viewing key generation unit 4 to generate a viewing key and viewing time limit information, and sends these data and content distribution channel information. The wireless communication unit 1 is controlled to transmit to the wireless communication terminal T using the registration channel.

 In addition, the communication control unit 10 controls the wireless communication unit 1 to transmit the content information encrypted by the encryption unit 7 to the wireless communication terminal T using the content distribution channel (more specifically, Content information is multicast-distributed to a plurality of wireless communication terminals existing in the communication area of the base station B). Furthermore, when the expiration date of the viewing key expires based on the viewing time limit information stored in the storage unit 6, the communication control unit 10 sends a new viewing key and the viewing key to the viewing key generation unit 4. Requests the generation of time limit information and requests the viewing key distribution channel selection unit 9 to determine the viewing key distribution channel, and uses the viewing key distribution channel to create a new (that is, updated) ) Control the wireless communication unit 1 so as to transmit the viewing key and the viewing time limit information to the wireless communication terminal T (more specifically, a new one is added to the plurality of wireless communication terminals existing in the communication area of the base station B). Multicast distribution of viewing keys and viewing time limit information). Details of the control process of the communication control unit 10 will be described later.

 On the other hand, in the wireless communication terminal T, the wireless communication unit 20 performs wireless communication with the base station B under the control of the communication control unit 27. The key input unit 21 includes dial keys, function keys, power keys, and the like, and outputs operation information of these keys to the communication control unit 27 as operation signals. The storage unit 22 stores in advance individual information and subscriber information of the wireless communication terminal T, a control program used by the communication control unit 27, and other various data, and responds to a request from the communication control unit 27. , The viewing key, viewing time limit information, continuous use key, continuous use time limit information, content distribution channel information, and content information transmitted from the base station B are stored.

  The decryption unit 23 acquires the viewing key and the content information from the storage unit 22 in response to a request from the communication control unit 27, decrypts the content information encrypted using the viewing key, and communicates with the communication control unit 27. Output to. The voice output unit 24 outputs voice and music to the outside based on the voice signal input from the communication control unit 27. The display unit 25 is, for example, a liquid crystal display, an organic EL display, or the like, and displays an image or the like based on a display signal input from the communication control unit 27.

  The viewing key distribution channel detection unit 26 acquires the viewing key and the continuous use key from the storage unit 22 in response to a request from the communication control unit 27, and based on the viewing key distribution channel selection algorithm using these as parameters. The key distribution channel for viewing is detected and the key distribution channel information for viewing is output to the communication control unit 27. That is, on the wireless communication terminal T side, the same communication channel as the viewing key distribution channel determined by the base station B is detected.

 The communication control unit 27 controls the overall operation of the wireless communication terminal T based on the control program stored in the storage unit 22, the operation signal input from the key input unit 21, the communication state of the wireless communication unit 20, and the like. Is. Further, when the communication control unit 27 makes a connection request to the multicast distribution service to the base station B, the communication control unit 27 uses the registration channel to store the individual information and the subscriber information stored in the storage unit 22. The wireless communication unit 20 is controlled to transmit to B.

The communication control unit 27 controls the wireless communication unit 20 to access the content distribution channel and receive the content information from the base station B, and requests the decoding unit 23 to decode the acquired content information. Based on the content information decoded by the decoding unit 23, an audio signal and a display signal are generated and output to the audio output unit 24 and the display unit 25.
Furthermore, the communication control unit 27 detects the viewing key distribution channel with respect to the viewing key distribution channel detection unit 26 when the viewing key expires based on the viewing time limit information stored in the storage unit 22. The wireless communication unit 20 is controlled to access the viewing key distribution channel and receive a new viewing key and viewing time limit information from the base station B.

  Next, the operation of the wireless communication system composed of such base station B and wireless communication terminal T will be described using the flowcharts of FIGS.

[When the user is a service subscriber]
First, the operation when the user of the wireless communication terminal T is a service subscriber, that is, a charging user (in the case of a specific wireless communication terminal T) will be described using the flowchart of FIG. It is assumed that the user has previously paid a subscription fee for the paid distribution service to a provider that performs the multicast distribution service, and has acquired subscriber information that proves that the user is a charged user (this subscriber information is stored in memory). Stored in the unit 22).

  First, when the communication control unit 27 of the wireless communication terminal T detects a connection instruction to the multicast distribution service from the user based on the operation signal input from the key input unit 21, the individual stored in the storage unit 22 is detected. Information and subscriber information is acquired, the wireless communication unit 20 is controlled to transmit these data to the base station B using the registration channel, and a connection request to the multicast distribution service is made to the base station B (Step S1).

  The individual information and subscriber information received by the wireless communication unit 1 of the base station B are output to the user authentication unit 2 via the communication control unit 10. Then, the user authentication unit 2 has accessed the base station B based on the plurality of individual information and subscriber information stored in the authentication information database 3 and the individual information and subscriber information of the wireless communication terminal T. An authentication process is performed to determine whether the user is a subscriber (charged user) of the multicast distribution service, and the authentication process result is output to the communication control unit 10 (step S2). Here, since the user has subscriber information, the user is authenticated as a service subscriber.

  Based on the authentication processing result that the user is a service subscriber, the communication control unit 10 requests the viewing key generation unit 4 to generate a viewing key and viewing time limit information indicating the expiration date, and Then, the continuous use key generation unit 5 is requested to generate the continuous use key and the continuous use time limit information indicating the expiration date (step S3). The viewing key generation unit 4 generates a viewing key and viewing time limit information in response to a request from the communication control unit 10, outputs the viewing key and viewing time limit information to the storage unit 6 and the communication control unit 10, and encrypts the viewing key. Output to. Further, the continuous use key generation unit 5 generates a continuous use key and continuous use time limit information in response to a request from the communication control unit 10 and outputs them to the storage unit 6 and the communication control unit 10. The expiration date of the viewing key is set to a period during which content information can be viewed for free (eg, 3 minutes), and the expiration date of the continuous use key is set to a period during which content information can be viewed for a fee (eg, 1 minute). Week).

 Then, the communication control unit 10 acquires the content distribution channel information from the storage unit 6, and uses the registration channel for the content distribution channel information and the viewing key, the viewing time limit information, the continuous use key, and the continuous use time limit information. The wireless communication unit 1 is controlled to transmit to the wireless communication terminal T (step S4).

  Subsequently, the communication control unit 10 requests the encryption unit 7 to encrypt the content information stored in the content information storage unit 8 (step S5). The encryption unit 7 encrypts the content information using the viewing key input from the viewing key generation unit 4 in response to a request from the communication control unit 10, and transmits the encrypted content information to the communication control unit 10 is output. The communication control unit 10 controls the wireless communication unit 1 to transmit the encrypted content information to the wireless communication terminal T using a content distribution channel that is a multicast channel (step S6). That is, the content information is multicast distributed to a plurality of wireless communication terminals existing in the communication area of the base station B.

  On the other hand, in the wireless communication terminal T, the communication control unit 27 stores the viewing key, viewing time limit information, continuous use key, continuous use time limit information, and content distribution channel information acquired from the base station B via the wireless communication unit 20. Store in unit 22. Then, based on the content distribution channel information, the communication control unit 27 controls the wireless communication unit 20 to access the content distribution channel and receive the content information.

  When acquiring the content information via the wireless communication unit 20, the communication control unit 27 stores the content information in the storage unit 22 and requests the decryption unit 23 to decrypt the content information (step S7). The decryption unit 23 acquires the viewing key and the content information from the storage unit 22 in response to a request from the communication control unit 27, decrypts the content information encrypted using the viewing key, and decrypts the decrypted content. Information is output to the communication control unit 27. The communication control unit 27 generates an audio signal or a display signal based on the content information decoded as described above, and outputs it to the audio output unit 24 and the display unit 25. The user can view the contents of the content information by the sound and music output from the audio output unit 24, the video displayed on the display unit 25, and the like.

  Subsequently, in the base station B, the communication control unit 10 determines whether or not the expiration date (3 minutes) of the viewing key has passed based on the viewing time limit information (step S8). In this step S8, if “NO”, that is, the expiration date of the viewing key has not elapsed, the communication control unit 10 returns to the operation of step S5, and “YES”, that is, the expiration date of the viewing key has elapsed. If it is determined that the request has been made, the viewing key generation unit 4 is requested to generate a new viewing key and viewing time limit information (step S9), and the viewing key distribution channel selection unit 9 is viewed. A request is made to determine a key distribution channel (step S10).

The viewing key generation unit 4 generates a new viewing key and viewing time limit information in response to a request from the communication control unit 10 and outputs the generated viewing key and the viewing time limit information to the storage unit 6 and the communication control unit 10. Is output to the encryption unit 7. In response to a request from the communication control unit 10, the viewing key distribution channel selection unit 9 obtains the previous viewing key and the continuous use key from the storage unit 6 and uses them as parameters. Based on the key distribution channel selection algorithm, the distribution channel of the updated viewing key is determined, and the viewing key distribution channel information is output to the communication control unit 10.
The continuous use key is a parameter that proves that the user has the right to access the viewing key distribution channel. If this continuous use key is not held, the viewing key distribution channel cannot be determined. It becomes. The case where the user does not hold the continuous use key will be described later in detail.

  The viewing key distribution channel is a multicast channel having a frequency band different from that of the content distribution channel, and a channel for normal communication that is not used in the communication area of the base station B at the time of determination is selected. Therefore, the viewing key distribution channel is not a fixed channel, but changes depending on the communication status in the communication area.

  On the other hand, the communication control unit 27 of the wireless communication terminal T similarly determines whether or not the expiration date of the viewing key has passed (step 11). If the expiration date of the viewing key has not elapsed in step S11, the communication control unit 27 returns to the operation of step S7. If it is determined that the expiration date of the viewing key has elapsed, the communication key 27 The distribution channel detection unit 26 is requested to detect the viewing key distribution channel (step S12). The viewing key distribution channel detection unit 26 acquires the viewing key and the continuous use key from the storage unit 22 in response to a request from the communication control unit 27, and based on the viewing key distribution channel selection algorithm using these as parameters. The key distribution channel for viewing is detected and the key distribution channel information for viewing is output to the communication control unit 27.

  The operations in steps S8 to S10 on the base station B side and the operations in steps S11 to S12 on the wireless communication terminal T side are performed substantially simultaneously. Then, both the base station B and the wireless communication terminal T use the same viewing key distribution channel based on the same viewing key distribution channel selection algorithm.

  Then, the communication control unit 10 of the base station B controls the wireless communication unit 1 to transmit the new viewing key and the viewing time limit information to the wireless communication terminal T using the viewing key distribution channel (step S13). ). That is, the new viewing key and the viewing time limit information are multicast distributed to a plurality of wireless communication terminals existing in the communication area of the base station B.

  The communication control unit 27 of the wireless communication terminal T controls the wireless communication unit 20 to access the viewing key distribution channel and receive a new viewing key and viewing time limit information. The communication control unit 27 stores the new viewing key and the viewing time limit information acquired via the wireless communication unit 20 in the storage unit 22.

  On the other hand, the communication control unit 10 of the base station B requests the encryption unit 7 to encrypt the content information using the new viewing key (step S14). In response to the request, the encryption unit 7 encrypts the content information by using the new viewing key input from the viewing key generation unit 4 and transmits the encrypted content information to the communication control unit 10. Output to. The communication control unit 10 controls the wireless communication unit 1 to transmit the content information encrypted with the new viewing key to the wireless communication terminal T using the content distribution channel (step S15).

 The communication control unit 27 of the wireless communication terminal T controls the wireless communication unit 20 to access the content distribution channel and receive content information. When acquiring the content information via the wireless communication unit 20, the communication control unit 27 stores the content information in the storage unit 22 and requests the decryption unit 23 to decrypt the content information (step S16).

 In response to a request from the communication control unit 27, the decryption unit 23 acquires a new viewing key and content information from the storage unit 22, and decrypts the encrypted content information using the new viewing key. The decrypted content information is output to the communication control unit 27. The communication control unit 27 generates an audio signal or a display signal based on the content information decoded as described above, and outputs it to the audio output unit 24 and the display unit 25.

  Thereafter, the base station B returns to the operation of step S8, updates the viewing key again when the viewing key is updated again, and wirelessly transmits the new viewing key and its viewing time limit information using the viewing key distribution channel. Multicast distribution to the communication terminal T. On the other hand, when the wireless communication terminal T returns to the operation of step S11 and the viewing key is updated again, the wireless communication terminal T accesses the viewing key distribution channel and receives a new viewing key and its viewing time limit information. Thus, even when the viewing key is updated, the billing user can continuously view the content information.

  Although not shown in FIG. 2, when the base station B determines that the expiration date (one week) of the continuous use key has passed based on the continuous use time limit information, it is paid to the wireless communication terminal T. A message for notifying the end of the service is transmitted. On the other hand, on the wireless communication terminal T side, when the expiration date (one week) of the continuous use key elapses, the continuous use key becomes unusable, and the viewing key distribution channel is accessed to acquire a new viewing key. The content information cannot be decrypted. In this way, when the expiration date of the continuous use key has elapsed, the user pays a subscription fee to the paid distribution service to the provider that performs the multicast distribution service again to acquire new subscriber information, and with the base station B By performing the authentication process, a new continuous use key can be acquired and content information can be viewed.

[When the user is a non-service subscriber]
Next, the operation when the user of the wireless communication terminal T is a non-service subscriber, that is, a non-billing user will be described using the flowchart of FIG. In this case, it is assumed that the user has not acquired the subscriber information that proves that the user is a billing user (not stored in the storage unit 22 of the wireless communication terminal T).

  First, when the communication control unit 27 of the wireless communication terminal T detects a connection instruction to the multicast distribution service from the user based on the operation signal input from the key input unit 21, the individual stored in the storage unit 22 is detected. The wireless communication unit 20 is controlled to acquire information and transmit these data to the base station B using the registration channel, and a connection request to the multicast distribution service is made to the base station B (step S20). .

  The individual information received by the wireless communication unit 1 of the base station B is output to the user authentication unit 2 via the communication control unit 10. Then, the user authenticating unit 2 multicasts the user who has accessed the base station B based on the plurality of individual information and subscriber information stored in the authentication information database 3 and the individual information of the wireless communication terminal T. An authentication process is performed to determine whether the user is a service subscriber (charging user), and the authentication process result is output to the communication control unit 10 (step S21). Here, since subscriber information is not transmitted from the wireless communication terminal T, the user authentication unit 2 authenticates that the user is a non-service subscriber (non-charged user).

  The communication control unit 10 requests the viewing key generation unit 4 to generate a viewing key and viewing time limit information indicating the expiration date based on the authentication processing result that the user is a non-service subscriber ( Step S22). When the user is a non-service subscriber, the communication control unit 10 does not request the continuous use key generation unit 5 to generate the continuous use key and the continuous use time limit information indicating the expiration date.

 The viewing key generation unit 4 generates a viewing key and viewing time limit information in response to a request from the communication control unit 10, outputs the viewing key and viewing time limit information to the storage unit 6 and the communication control unit 10, and encrypts the viewing key. Output to. The expiration date of the viewing key is set to a period during which content information can be viewed for free (eg, 3 minutes).

 Then, the communication control unit 10 acquires the content distribution channel information from the storage unit 6 and transmits the content distribution channel information, the viewing key and the viewing time limit information to the wireless communication terminal T using the registration channel. The wireless communication unit 1 is controlled (step S23).

  Subsequently, the communication control unit 10 requests the encryption unit 7 to encrypt the content information stored in the content information storage unit 8 (step S24). The encryption unit 7 encrypts the content information using the viewing key input from the viewing key generation unit 4 in response to a request from the communication control unit 10, and transmits the encrypted content information to the communication control unit 10 is output. The communication control unit 10 controls the wireless communication unit 1 to transmit the encrypted content information to the wireless communication terminal T using a content distribution channel that is a multicast channel (step S25).

  On the other hand, in the wireless communication terminal T, the communication control unit 27 stores the viewing key, viewing time limit information, and content distribution channel information acquired from the base station B via the wireless communication unit 20 in the storage unit 22. Then, based on the content distribution channel information, the communication control unit 27 controls the wireless communication unit 20 to access the content distribution channel and receive the content information.

  When acquiring the content information via the wireless communication unit 20, the communication control unit 27 stores the content information in the storage unit 22 and requests the decryption unit 23 to decrypt the content information (step S26). The decryption unit 23 acquires the viewing key and the content information from the storage unit 22 in response to a request from the communication control unit 27, decrypts the content information encrypted using the viewing key, and decrypts the decrypted content. Information is output to the communication control unit 27. The communication control unit 27 generates an audio signal or a display signal based on the content information decoded as described above, and outputs it to the audio output unit 24 and the display unit 25. The non-billing user can view the contents of the content information by the sound and music output from the audio output unit 24, the video displayed on the display unit 25, and the like.

  Subsequently, in the base station B, the communication control unit 10 determines whether or not the expiration date (3 minutes) of the viewing key has passed based on the viewing time limit information (step S27). In this step S27, if “NO”, that is, the expiration date of the viewing key has not elapsed, the communication control unit 10 returns to the operation of step S24, and “YES”, that is, the expiration date of the viewing key has elapsed. If it is determined that the request has been made, the viewing key generation unit 4 is requested to generate a new viewing key and viewing time limit information (step S28), and the viewing key distribution channel selection unit 9 performs viewing. A request is made to determine a key distribution channel (step S29).

  The viewing key generation unit 4 generates a new viewing key and viewing time limit information in response to a request from the communication control unit 10 and outputs the generated viewing key and the viewing time limit information to the storage unit 6 and the communication control unit 10. Is output to the encryption unit 7. The viewing key distribution channel selection unit 9 acquires the viewing key and the continuous use key before being updated from the storage unit 6 in response to a request from the communication control unit 10, and uses the viewing key distribution channel as a parameter. Based on the selection algorithm, the distribution channel of the updated viewing key is determined, and the viewing key distribution channel information is output to the communication control unit 10. The continuous use key used here is one that has been distributed to other billing users.

  On the other hand, the communication control unit 27 of the wireless communication terminal T similarly determines that the viewing key has expired (step 30). In step S30, when the expiration date of the viewing key has not elapsed, the communication control unit 27 returns to the operation of step S26, and when it is determined that the expiration date of the viewing key has elapsed, The distribution channel detector 26 is requested to determine a viewing key distribution channel (step S31). The viewing key distribution channel detection unit 26 acquires the viewing key from the storage unit 22 in response to a request from the communication control unit 27, and tries to detect the viewing key distribution channel based on the viewing key distribution channel selection algorithm. However, since the continuous use key does not exist, the viewing key distribution channel information indicating that the viewing key distribution channel cannot be determined is output to the communication control unit 27.

  The operations in steps S27 to S29 on the base station B side and the operations in steps S30 to S31 on the wireless communication terminal T side are performed substantially simultaneously. The base station B side determines the viewing key distribution channel, but the wireless communication terminal T, which is a non-billing user, does not detect the viewing key distribution channel.

  Then, the communication control unit 10 of the base station B controls the wireless communication unit 1 to transmit the new viewing key and the viewing time limit information to the wireless communication terminal T using the viewing key distribution channel (step S32). ). That is, the new viewing key and its viewing time limit information are multicast-distributed to a plurality of wireless communication terminals existing in the communication area of the base station B, and only the charging user can acquire the new viewing key and its viewing time limit information. .

On the other hand, the communication control unit 27 of the wireless communication terminal T, which is a non-billing user, cannot access the viewing key distribution channel and cannot acquire a new viewing key and viewing time limit information.
Thus, the non-billing user can view the content information for free only for 3 minutes, which is the expiration date of the viewing key, but cannot obtain a new viewing key after 3 minutes.
Even if the subsequent content information is acquired, it cannot be decoded and viewed.

  On the base station B side, the individual information of the wireless communication terminal T of the accessing non-billing user is stored, and when the non-billing user who once distributed the viewing key accesses again, the authentication process is performed. It is desirable to provide a function that prevents the viewing key from being transmitted at the time.

  As described above, according to the present embodiment, the updated viewing key is distributed using the viewing key distribution channel accessible only by the charging user, and the viewing key distribution channel is communicated within the communication area. It is possible to improve safety by sequentially changing according to the state. Since the viewing key distribution channel is a multicast channel, it is possible to achieve both efficient use of radio resources and improved safety by multicast distribution of the viewing key. Furthermore, according to this embodiment, it is possible to easily provide a free viewing service to non-billing users.

  In the above-described embodiment, the wireless communication system that performs the multicast distribution service has been described as an example. However, the present invention is not limited to this, and the present invention can be similarly applied to a wireless communication system that performs the broadcast distribution service.

1 is a configuration block diagram of a wireless communication system according to an embodiment of the present invention. It is a 1st flowchart which shows operation | movement of the radio | wireless communications system which concerns on one Embodiment of this invention. It is a 2nd flowchart which shows operation | movement of the radio | wireless communications system which concerns on one Embodiment of this invention.

Explanation of symbols

B ... base station, 1 ... wireless communication unit, 2 ... user authentication unit, 3 ... authentication information database, 4 ... viewing key generation unit, 5 ... continuous use key generation unit, 6 ... storage unit, 7 ... encryption unit, DESCRIPTION OF SYMBOLS 8 ... Content information storage part, 9 ... Viewing key distribution channel selection part, 10 ... Communication control part, T ... Wireless communication terminal, 20 ... Wireless communication part, 21 ... Key input part, 22 ... Storage part, 23 ... Decryption , 24 ... audio output unit, 25 ... display unit, 26 ... viewing key distribution channel detection unit, 27 ... communication control unit

Claims (7)

A wireless communication method for transmitting distribution information from an information distribution device to a wireless communication terminal,
On the information distribution device side,
Encrypting the delivery information;
Detecting an encrypted information distribution channel for distributing encrypted information used for the encryption to a specific wireless communication terminal;
Transmitting encrypted information using the encrypted information delivery channel;
In the specific wireless communication terminal,
Receiving encrypted information on the encrypted information delivery channel;
And a step of decrypting the encrypted distribution information based on the encrypted information. On the information distribution device side,
Determining whether or not the wireless communication terminal that has made the request is a specific wireless communication terminal based on an information distribution request from the wireless communication terminal;
When the wireless communication terminal is a specific wireless communication terminal, transmitting use permission information for permitting use of the channel for encrypted information distribution to the specific wireless communication terminal;
The specific wireless communication terminal is
Detecting the encrypted information delivery channel when receiving the use permission information;
Receiving encrypted information on the detected encrypted information delivery channel; and
The wireless communication method according to claim 1. On the information distribution device side,
Updating to change the encryption information over a period of time;
Detecting a new encrypted information distribution channel for distributing the updated encrypted information to a specific wireless communication terminal; and
Distributing the updated encrypted information from the information distribution device to the specific wireless communication terminal via the detected encrypted information distribution channel;
The specific wireless communication terminal is
Receiving updated encrypted information on the encrypted information delivery channel;
Further comprising the step of decrypting the encrypted distribution information based on the updated encrypted information.
The wireless communication method according to claim 1 or 2. A predetermined expiration date is set in the use permission information, and when the expiration date has passed,
The wireless communication method according to claim 2 or 3, wherein the specific wireless communication terminal does not detect the channel for distributing the encrypted information.  The wireless communication method according to claim 1, wherein the information distribution device detects the encrypted information distribution channel according to a communication state. An information distribution device for transmitting distribution information to a wireless communication terminal,
An encryption means for encrypting the distribution information;
Encrypted information distribution channel detecting means for detecting a channel for distributing encrypted information for distributing encrypted information used for the encryption to a specific wireless communication terminal;
And a communication control means for transmitting encrypted information using the encrypted information distribution channel. A wireless communication terminal capable of receiving distribution information from an information distribution device,
Terminal-side communication control means for receiving encrypted information used for encryption of the distribution information distributed from the information distribution device via an encrypted information distribution channel;
A wireless communication terminal comprising: decrypting means for decrypting the encrypted distribution information based on the encrypted information.

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