JP2006121760A - Data communication system and data communication method, data transmitting apparatus and data transmitting method, data receiving apparatus and data receiving method, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate whether a communication party of content data is located on a LAN or located over a WAN. <P>SOLUTION: In a step S13, the difference between a received counter value of a packet for check and the value of a register is operated. In a step S14, it is judged whether or not the operated difference is equal with a fixed value X and if judged equal, the counter value of the packet is recorded in the register in a step S15. In a step S16, it is judged whether or not the packets for check of a predetermined number are received and if judged received, LAN connection is judged in a step S17. If it is judged in the step S14 that the operated difference is not equal with the fixed value X, WAN connection is judged in a step S18. The present invention may be applied to a personal computer or the like comprising a wireless LAN. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data communication system and a data communication method, a data transmission device and a data transmission method, a data reception device and a data reception method, and a program, and in particular, data communication is located via a WAN represented by the Internet. A data communication system and a data communication method, a data transmission apparatus and a data transmission method, which are suitable for use in determining whether the communication is limited to the same LAN as the self provided in the house or the like, The present invention relates to a data receiving apparatus, a data receiving method, and a program.

  In recent years, the widespread use of public-wide networks such as the Internet (hereinafter referred to as WAN), and the spread of local networks (hereinafter referred to as LAN) installed in general houses and the communication rate Along with improvements, personal computers and various electronic AV devices are connected via a LAN or WAN to communicate various data.

  The spread of such network technology enables content data such as video data, audio data, and program data to be quickly sold or shared personally. However, on the other hand of such convenience, content data that is a copyrighted work is illegally distributed, and various countermeasures have been proposed.

  For example, in a music download service, the storage destination of downloaded audio data is limited to only a recording medium on which a predetermined copy prevention measure is applied.

In addition, for example, for content data communication in a small network such as IEEE1394, there is a mechanism in which authentication is executed, and then the content data is encrypted and communicated to prevent content data from being supplied to unauthorized devices. It has been introduced (for example, see Non-Patent Document 1).
Digital Transmission Content Protection Specification Volume1 (Informational Version), Hitachi, Ltd., Intel Corporation, Matsushita Electric Industrial Co., Ltd., Sony Corporation, Toshiba Corporation, Revision1.2a, February 25,2002

  However, there is still no established mechanism for communicating content data while preventing unauthorized distribution using the IP protocol adopted for communication over the WAN. When communicating content data with the IP protocol, it is conceivable to limit the communicable range within the LAN to prevent unauthorized distribution. In order to restrict communication of content data within the LAN, it is necessary to determine whether the communication partner of the content data is located in the LAN or over the WAN. There has been a problem that a method for determining such a situation has not been established.

  The present invention has been made in view of such a situation, and an object of the present invention is to make it possible to determine whether a communication partner of content data is located on a LAN or a WAN. And

  A data communication system according to a first aspect of the present invention is a data communication system including a data transmission apparatus and a data reception apparatus connected via a network, wherein the data communication apparatus checks the data reception apparatus. A reception notification message for the check packet transmitted from the data reception device and a first transmission means for transmitting a packet, including reception notification information generated based on shared data shared with the data reception device First reception means for receiving the received reception notification message, calculation means for calculating an expected value of the reception notification information based on the shared data shared with the data reception device, the reception notification information, and the reception notification information A comparison means for comparing the expected value of the received message and a response time of the reception notification message is shorter than a predetermined threshold value. And determining means for determining permission of data transmission to the data receiving apparatus based on the comparison result of the comparing means and the determination result of the determining means, and the data receiving apparatus includes the data transmission Second reception means for receiving a check packet from a device, reception notification information generation means for generating reception notification information based on shared data shared with the data transmission device on the premise of predetermined processing, and for the check packet A reception notification message generating means for generating a reception notification message including the reception notification information; and when the check packet transmitted by the data transmission device is received by the reception means, the data transmission Second transmission means for transmitting the reception notification message to a device.

  A data communication method according to a first aspect of the present invention is a data communication method of a data communication system including a data transmission device and a data reception device connected via a network, and the data reception device in the data communication device. A first transmission step of transmitting a check packet to the data reception device, a first reception step of receiving a check packet from the data transmission device in the data reception device, and the data transmission device in the data reception device; A reception notification information generation step for generating reception notification information based on shared data shared on the assumption of a predetermined process, and a reception notification message for the check packet in the data reception device, including the reception notification information Reception notification message generator that generates a reception notification message A second transmission step of transmitting the generated reception notification message to the data transmission device in the data reception device, and the check packet transmitted from the data reception device in the data communication device. A second reception step of receiving a reception notification message including reception notification information generated based on shared data shared with the data reception device; and the data in the data communication device A calculation step of calculating an expected value of the reception notification information based on the shared data shared with the receiving device, and a comparison step of comparing the reception notification information and the expected value of the reception notification information in the data communication device; The response time of the reception notification message in the data communication device is a predetermined threshold value. Comprising a determining step that is short, in the data communication apparatus, based on the determination result of said determining step and the comparison result of the comparing step, a determination step of determining whether to allow the data transmission to the data receiving apparatus.

  In the first aspect of the present invention, the data communication device transmits a check packet to the data receiving device, the data receiving device receives the check packet from the data transmitting device, and the data transmitting device and the predetermined process. The reception notification information is generated based on the shared data shared on the assumption that the reception notification message is received for the check packet, and the reception notification message including the reception notification information is generated and transmitted to the data transmission apparatus. Then, the data communication device receives a reception notification message for the check packet transmitted from the data reception device, which includes reception notification information generated based on shared data shared with the data reception device. The expected value of the reception notification information is calculated based on the shared data shared with the data receiving device, the reception notification information is compared with the expected value, and the response time of the reception notification message is shorter than a predetermined threshold value. Based on the comparison result and the determination result, permission of data transmission to the data receiving device is determined.

  According to a second aspect of the present invention, there is provided a data transmission device including: a data transmission device that transmits data; a transmission unit that transmits a check packet to the data reception device; and the check packet transmitted from the data reception device. A reception notification message including a reception notification message including reception notification information generated based on shared data shared with the data receiving device; and the shared data shared with the data receiving device. Based on the calculation means for calculating the expected value of the reception notification information, the comparison means for comparing the reception notification information with the expected value of the reception notification information, and the response time of the reception notification message is shorter than a predetermined threshold Based on the comparison result of the comparison means and the determination result of the determination means. And a determining means for determining permission of data transmission to be.

  The transmitting means may transmit a check packet to the data receiving device a predetermined number of times.

  The transmitting means may transmit a check packet to the data receiving apparatus using TCP.

  The transmitting means may transmit a check packet to the data receiving apparatus using UDP.

  The data transmission device is connected to a first network, and the determination unit is different from the first network in the data reception device based on a comparison result of the comparison unit and a determination result of the determination unit. It is possible to identify whether or not it is connected to the second network and to determine permission of data transmission to the data receiving device based on the identification result.

  The first network may be a LAN, and the second network may be a WAN.

  A data transmission method according to a second aspect of the present invention is a data transmission method of a data transmission device that transmits data, a transmission step of transmitting a check packet to the data reception device, and a transmission from the data reception device. A reception notification message for the check packet, the reception step including reception notification message including reception notification information generated based on shared data shared with the data reception device; and sharing with the data reception device A calculation step of calculating an expected value of the reception notification information based on the shared data, a comparison step of comparing the reception notification information with an expected value of the reception notification information, and a response time of the reception notification message is a predetermined value. A determination step for determining that the value is shorter than the threshold, a comparison result of the comparison step, and the determination step. Based on the determination result, and a determination step of determining whether to allow the data transmission to the data receiving apparatus.

  The program according to the second aspect of the present invention is a transmission means for transmitting a check packet to a data receiving device, and a reception notification message for the check packet transmitted from the data receiving device, wherein the data receiving device A program for controlling a data transmission apparatus, comprising: a reception unit configured to receive a reception notification message including reception notification information generated based on shared data shared with the data sharing apparatus; A calculation step of calculating an expected value of the reception notification information based on the data, a comparison step of comparing the reception notification information and the expected value of the reception notification information, and a response time of the reception notification message is less than a predetermined threshold A determination step for determining shortness, a comparison result of the comparison step, and a determination result of the determination step. Can, to execute processing including the determination step of determining whether to allow the data transmission to the data receiving device to the computer.

  In the second aspect of the present invention, a reception notification message for a check packet transmitted from a data reception device, including reception notification information generated based on shared data shared with the data reception device An expected value of the reception notification information is calculated based on shared data shared with the data receiving device when the message is received, the reception notification information is compared with the expected value, and the response time of the reception notification message is a predetermined threshold value. Is determined to be shorter, and based on the comparison result and the determination result, permission of data transmission to the data receiving device is determined.

  A data receiving apparatus according to a third aspect of the present invention is a data receiving apparatus for receiving data from a data transmitting apparatus that determines whether to permit data transmission based on reception notification information and a response time. A receiving unit that receives a check packet from a transmitting device; a reception notification information generating unit that generates reception notification information based on shared data shared with the data transmitting device on the premise of a predetermined process; and a reception notification for the check packet A reception notification message generating unit that generates a reception notification message including the reception notification information, and when the check packet transmitted by the data transmission device is received by the reception unit, the data transmission device Transmitting means for transmitting the reception notification message.

  The receiving means may receive the check packet transmitted a predetermined number of times from the data transmitting apparatus.

  The receiving means may receive the check packet transmitted from the data transmitting apparatus using TCP.

  The receiving means may receive the check packet transmitted from the data transmitting apparatus using UDP.

  The data transmission device may be connected to a first network, and the data reception device may be connected to a second network different from the first network.

  The first network may be a LAN, and the second network may be a WAN.

  A data reception method according to a third aspect of the present invention is a data reception method for a data reception apparatus that receives data from a data transmission apparatus that determines whether to permit data transmission based on reception notification information and a response time. A reception step of receiving a check packet from the data transmission device, a reception notification information generation step of generating reception notification information based on shared data shared with the data transmission device on the assumption of a predetermined process, and the check A reception notification message for a packet, the reception notification message generating step for generating a reception notification message including the reception notification information, and the check packet transmitted by the data transmission device in the processing of the reception step is received A transmission step of transmitting the reception notification message to the data transmission device. Including the door.

  A program according to a third aspect of the present invention is a program for controlling a data receiving apparatus that receives data from a data transmitting apparatus that determines whether to permit data transmission based on reception notification information and a response time. A reception notification information generation step for generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device, and a reception notification message for a check packet from the data transmission device, A reception notification message generation step of generating a reception notification message including the reception notification information; and a transmission step of transmitting the reception notification message to the data transmission device when the check packet is received from the data transmission device; Causes the computer to execute processing including

  In the third aspect of the present invention, a check packet from a data transmission device is received, reception notification information is generated based on shared data shared with the data transmission device on the premise of a predetermined process, and A reception notification message including reception notification information is generated and transmitted to the data transmission device.

  According to the present invention, it is possible to determine whether a communication partner of content data is located on a LAN or a WAN.

  FIG. 1 shows a configuration example of a communication system including a LAN composed of a personal computer, AV equipment, and the like according to an embodiment of the present invention. In this communication system, a LAN 1, a LAN 7, and a server 8 are connected to each other via a WAN 6 represented by the Internet.

  The LAN 1 is composed of personal computers (PCs) 3 and 4 and an AV device 5 connected via a switching hub 2. For example, the LAN 1 is provided in a house and a specific individual (or family) is provided. It is of a scale that can be used. The switching hub 2 is connected to the personal computers 3 and 4 and the AV device 5 by a high-speed interface such as Ethernet (registered trademark) (100BASE-TX). In between, for example, data communication is possible at a communication rate of about 100 Mbps and a sufficiently low error rate. The personal computers 3 and 4 and the AV device 5 can be connected to the LAN 7 or the server 8 via the switching hub 2 and the WAN 6.

  When the personal computer 3 communicates content data, is the communication partner located on the LAN 1 (for example, the personal computer 4) or is located over the WAN 6 (for example, the server 8)? Has been made to judge.

Similarly, when the personal computer 4 and the AV device 5 communicate content data, the personal computer 4 and the AV device 5 are those whose communication counterparts are located on the LAN 1 (for example, the personal computer 3) or those that are located via the WAN 6 (for example, The server 8) is determined.

  The LAN 7 is configured in the same manner as the LAN 1, but is managed by another user different from the user of the LAN 1. The server 8 is managed by a user different from the LAN 1 user or the LAN 7 user.

  FIG. 2 shows a configuration example of the personal computer 3. The personal computer 3 includes a CPU (Central Processing Unit) 21. An input / output interface 25 is connected to the CPU 21 via the bus 24. A ROM (Read Only Memory) 22 and a RAM (Random Access Memory) 23 are connected to the bus 24.

  The input / output interface 25 stores an input unit 26 including an input device such as a keyboard and a mouse for a user to input an operation command, an output unit 27 for outputting a video signal to a display such as an operation screen, a program, and various data. A storage unit 28 including a hard disk drive and the like, an Ethernet (registered trademark) interface, and the like are connected to the switching hub 2 via a 100BASE-TX cable or the like, and a communication unit 29 that communicates data via the switching hub 2 is connected. .

  The communication unit 29 may use a high-speed interface such as USB (Universal Serial Bus) or IEEE (Institute of Electrical and Electronics Engineers) 1394 instead of the Ethernet (registered trademark) interface.

  Further, a drive 30 for reading / writing data from / to a recording medium such as the magnetic disk 31, the optical disk 32, the magneto-optical disk 33, and the semiconductor memory 34 is connected.

  The CPU 21 executes various processes described later according to programs stored in the ROM 22 or read from the magnetic disk 31 to the semiconductor memory 34 and stored in the storage unit 28 and loaded from the storage unit 28 to the RAM 23. The RAM 23 also appropriately stores data necessary for the CPU 21 to execute various processes.

  FIG. 3 shows a first configuration example of functional blocks realized by the communication unit 29 operating according to the control of the CPU 21. The control unit 41 controls a transmission / reception unit 43 that transmits / receives data according to UDP (User Datagram Protocol) which is a kind of communication protocol. In addition, the control unit 41 performs reading / writing on the register 42. The transmission / reception unit 43 communicates the content data according to the control of the control unit 41. In order to determine whether the communication partner is located in the LAN 1 or the WAN 6 prior to the content data. A predetermined number of check packets are communicated.

  FIG. 4 shows an example of a check packet. A feature of this check packet is that the counter value generated by the control unit 41 is recorded in the payload.

  It is assumed that the personal computer 4 and the AV device 5 also have the same functional blocks as hardware or software as the communication unit 29 shown in FIG. Further, the same applies to various devices and the server 8 constituting the LAN 7.

  Here, the outline | summary which judges whether the communicating party of data is located in LAN1 or is located via WAN6 by the 1st structural example of the communication part 29 is demonstrated.

  In the communication protocol UDP, when a communication error occurs, a packet that is not correctly communicated is discarded, and retransmission thereof is not executed. Using such characteristics, it is determined whether the data communication partner is located on the LAN 1 or the WAN 6.

  More specifically, in communication with a partner located on the LAN 1, all the packets transmitted at a high communication rate are received by the receiving side without changing the transmission order by the operation of the switching hub 2. On the other hand, communication with a partner located via the WAN 6 causes a communication error in communication at a high rate due to its wide area, and a packet is discarded due to the characteristics of UDP. The data communication partner is located in the LAN 1 or is located via the WAN 6 based on the fact that it may not be received or may be received in an order different from the order in which it was transmitted. Determine what you want to do.

  Next, the transmission process by the 1st structural example of the communication part 29 shown by FIG. 3 is demonstrated with reference to the flowchart of FIG. This transmission process is a process for determining whether the communication partner is located on the LAN 1 or the partner located via the WAN 6 prior to content data communication.

  In step S <b> 1, the control unit 41 sets a counter value (counter value) built therein to an initial value A. In step S <b> 2, the control unit 41 increments the counter by a fixed number X and outputs the counter value to the transmission / reception unit 43. In step S <b> 3, based on the control of the control unit 41, the transmission / reception unit 43 records the counter value input from the control unit 41 in the payload of the check packet and transmits it to the transmission destination.

  In step S <b> 4, the control unit 41 determines whether or not a predetermined number of check packets have been transmitted by the transmission / reception unit 43. If it is determined that a predetermined number of check packets have not been transmitted, the process returns to step S2, and the subsequent processes are repeated. Thereafter, when it is determined in step S4 that a predetermined number of check packets have been transmitted, this transmission process is terminated. Through the transmission processing described above, a plurality of check packets in which a continuous count value is recorded are transmitted to the reception side.

  Next, the reception process by the 1st structural example of the communication part 29 provided in the receiving side corresponding to the transmission process mentioned above is demonstrated with reference to the flowchart of FIG. In step S <b> 11, the control unit 41 records the initial value A in the register 42. In step S12, the transmission / reception unit 43 stands by until a check packet transmitted from the transmission side is received. When the check packet is received, the process proceeds to step S13.

  In step S <b> 13, the control unit 41 calculates a difference between the counter value recorded in the payload of the check packet received in step S <b> 12 and the value recorded in the register 42. In step S14, it is determined whether or not the difference calculated in step S13 is equal to the fixed value X. If it is determined that the difference is equal to the fixed value X, the check packet is not lost and is received in the order of transmission, and thus the process proceeds to step S15.

  In step S15, the control unit 41 records the counter value recorded in the packet in step S13 in the register 42. In step S <b> 16, the control unit 41 determines whether the transmission / reception unit 43 has received a predetermined number of check packets. If it is determined that the predetermined number of check packets have not been received, the process returns to step S12, and the subsequent processes are repeated. Thereafter, when it is determined in step S16 that a predetermined number of check packets have been received, the process proceeds to step S17.

  In step S <b> 17, the control unit 41 determines that the connection is a LAN connection, that is, the transmission side is located on the LAN 1.

  If it is determined in step S14 that the difference calculated in step S13 is not equal to the fixed value X, the check packet is missing or received in an order different from the order in which it was transmitted. Proceed to S18. In step S <b> 18, the control unit 41 determines that the connection is a WAN connection, that is, the transmission side is located via the WAN 6. This is the end of the description of the reception process.

  For example, if it is determined that this is a WAN connection by this reception process, the usage method of content data transmitted from the transmission side after that will be tightened, and conversely, if it is determined that it is a LAN connection If the restriction on how to use the content data sent from the sender is relaxed after this, the content data will be distributed over the WAN without obstructing private use of the content data on the LAN. It becomes possible to deter.

  Next, FIG. 7 shows a second configuration example of functional blocks realized by the communication unit 29 operating according to the control of the CPU 21. The control unit 51 controls the transmission / reception unit 53 that transmits / receives data according to the communication protocol TCP or UDP. In addition, the control unit 51 performs reading / writing on the register 52. The transmission / reception unit 53 communicates the content data according to the control of the control unit 51, but in order to determine whether the communication partner is located on the LAN 1 or via the WAN 6 in advance. A predetermined number of check packets are communicated. The timer 54 measures time according to the control of the control unit 51.

  It is assumed that the personal computer 4 and the AV device 5 also have the same functional blocks as hardware or software as the communication unit 29 shown in FIG. Further, the same applies to various devices and the server 8 constituting the LAN 7.

  Here, the outline | summary which judges whether the communicating party of data is located in LAN1 or is located via WAN6 by the 2nd structural example of the communication part 29 is demonstrated. The communication with the partner located on the LAN 1 can secure a high-speed communication rate by the operation of the switching hub 2. On the other hand, the communication rate of the communication with the partner located via the WAN 6 is lower than the communication rate via the LAN 1 due to various factors. Based on this, it is determined whether the data communication partner is located on the LAN 1 or the counterpart located via the WAN 6.

  A reception process according to the second configuration example of the communication unit 29 will be described with reference to a flowchart of FIG. This reception process is started when a check packet is transmitted from the transmission side.

  In step S21, the control unit 51 determines whether or not the transmission / reception unit 53 has received a predetermined number of check packets, and waits until it is determined that a predetermined number of check packets have been received. If it is determined that a predetermined number of check packets have been received, the process proceeds to step S22. In step S <b> 22, the control unit 51 generates reception notification information indicating that a predetermined number of check packets have been received, and outputs the reception notification information to the transmission / reception unit 53. In step S23, the transmission / reception unit 53 returns reception notification information to the transmission side. It is desirable for safety that this reception notification information cannot be forged by a third party. For example, a specific example is conceivable in which secret information shared between the receiving side and the transmitting side is used as key information, and the result of keyed hash processing on all or part of the data included in the check packet is used. This is the end of the description of the reception process.

  Next, the transmission process by the 2nd structural example of the communication part 29 is demonstrated with reference to the flowchart of FIG. In step S31, the control unit 51 transmits a predetermined number of check packets as a waiting time for the timer 54, and is necessary for receiving the reception notification information returned from the transmission side located in the LAN 1 correspondingly. Set enough time.

  In step S <b> 32, the timer 54 starts measuring time according to the control of the control unit 51. In step S <b> 33, the transmission / reception unit 53 transmits a predetermined number of check packets based on the control of the control unit 51. In the payload of the check packet, for example, a different random number may be recorded for each check. On the receiving side, by generating the reception notification information by the above-described keyed hash process, it is possible to prevent the reception notification information from being illegally generated.

  In step S <b> 34, the control unit 51 determines whether or not the reception notification information returned from the reception side is received by the transmission / reception unit 53. If it is determined that the reception notification information has not been received, the process proceeds to step S35. In step S35, the control unit 51 refers to the timer 54 and confirms whether or not the waiting time set in step S31 has elapsed. If it is determined that the waiting time has not elapsed, the process returns to step S34, and the subsequent processes are repeated.

  In step S34, when it is determined by the transmission / reception unit 53 that the reception notification information returned from the reception side has been received, the process proceeds to step S36. In step S36, the control unit 51 confirms whether the reception notification information is correct. If it is determined that it is not correct, the process proceeds to step S38. Otherwise, the process proceeds to step S37. In step S37, the control unit 51 determines that the connection is a LAN connection, that is, the reception side is located on the LAN 1. As a specific confirmation method of the reception notification information, it is conceivable to obtain the expected value of the reception notification information by the same process as that performed on the transmission side on the transmission side and to compare it with that obtained from the reception side. .

  If it is determined in step S35 that the waiting time has elapsed, the process proceeds to step S38. In step S <b> 38, the control unit 51 determines that the connection is WAN, that is, the reception side is located via the WAN 6. This is the end of the description of the transmission process.

  For example, if it is determined by this transmission processing that the connection is WAN, the transmission of the content data to the receiving side after that is canceled, and conversely, if it is determined that the connection is LAN, the subsequent content data If the transmission of the content data is permitted, it is possible to prevent the content data from being distributed via the WAN without hindering private use of the content data on the LAN.

  Next, as a third method, a case will be described in which the communication unit 29 complies with another communication protocol, TCP (Transmission Control). In the communication protocol TCP, when a communication error occurs, it is retransmitted until all packets are correctly communicated. Therefore, when communication is performed according to TCP at a high rate that cannot be maintained in the WAN, if the communication is with the one located in the LAN 1, no re-transmission occurs, but the communication with the one located through the WAN 6 is possible. In this case, it is considered that retransmission occurs.

  Hereinafter, a transmission process for determining whether the data reception side is located on the LAN 1 or the WAN 6 on the transmission side using the characteristics of the communication protocol TCP will be described. This will be described with reference to FIG. This transmission process is executed prior to the communication of content data. In this case, the configuration of the communication unit 29 is the same as that shown in FIG.

  In step S <b> 41, the transmission / reception unit 43 starts check packet transmission based on the control of the control unit 41. In step S <b> 42, the control unit 41 determines whether the transmission / reception unit 43 has retransmitted the check packet. If it is determined that retransmission of the check packet has occurred, the process proceeds to step S43.

  In step S43, the control unit 41 determines that the connection is a WAN connection, that is, the reception side is located via the WAN 6.

  If it is determined in step S42 that the check packet has not been retransmitted, the process proceeds to step S44. In step S <b> 44, the control unit 41 determines whether a predetermined number of check packets have been transmitted by the transmission / reception unit 43. If it is determined that a predetermined number of check packets have not been transmitted, the process returns to step S42, and the subsequent processes are repeated. Thereafter, when it is determined in step S44 that a predetermined number of check packets have been transmitted, the process proceeds to step S45.

  In step S45, the control unit 41 determines that the connection is a LAN connection, that is, the transmission side is located in the LAN1. This is the end of the description of the transmission process.

  For example, if it is determined by this transmission processing that the connection is WAN, the transmission of the content data to the receiving side after that is canceled, and conversely, if it is determined that the connection is LAN, the subsequent content data If the transmission of the content data is permitted, it is possible to prevent the content data from being distributed via the WAN without hindering private use of the content data on the LAN.

  In the present specification, the step of describing the program recorded in the recording medium is not limited to the processing performed in time series according to the described order, but is not necessarily performed in time series, either in parallel or individually. The process to be executed is also included.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

It is a block diagram which shows the structural example of the communication system to which this invention is applied. It is a block diagram which shows the structural example of the personal computer shown by FIG. 3 is a first configuration example of the communication unit 29 shown in FIG. 2. It is a figure which shows an example of the packet for a check. 5 is a flowchart for explaining a transmission process according to a first configuration example of a communication unit 29. 6 is a flowchart illustrating a reception process according to a first configuration example of a communication unit 29. FIG. 3 is a second configuration example of the communication unit 29 shown in FIG. 2. FIG. 12 is a flowchart illustrating a reception process according to a second configuration example of the communication unit 29. 10 is a flowchart illustrating a transmission process according to a second configuration example of the communication unit 29. It is a flowchart explaining the transmission process at the time of complying with the TCP communication protocol.

Explanation of symbols

  1 LAN, 2, 3 personal computer, 6 WAN, 7 LAN, 8 server, 21 CPU, 29 communication unit, 31 magnetic disk, 32 optical disk, 33 magneto-optical disk, 34 semiconductor memory, 41 control unit, 42 register, 43 transmission / reception Section, 51 control section, 52 register, 53 transceiver section, 54 timer

Claims (18)

In a data communication system composed of a data transmission device and a data reception device connected via a network,
The data communication device includes:
First transmitting means for transmitting a check packet to the data receiving device;
A reception notification message for the check packet transmitted from the data reception device, the reception notification message including reception notification information generated based on shared data shared with the data reception device; Receiving means;
Calculation means for calculating an expected value of the reception notification information based on the shared data shared with the data receiving device;
Comparison means for comparing the reception notification information with an expected value of the reception notification information;
Determining means for determining that a response time of the reception notification message is shorter than a predetermined threshold;
Based on the comparison result of the comparison means and the determination result of the determination means, and a determination means for determining permission of data transmission to the data receiving device,
The data receiving device is:
Second receiving means for receiving a check packet from the data transmitting device;
Reception notification information generating means for generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device;
A reception notification message for the check packet, a reception notification message generating means for generating a reception notification message including the reception notification information;
A data communication system comprising: a second transmission unit configured to transmit the reception notification message to the data transmission device when the check packet transmitted from the data transmission device is received by the reception unit. In a data communication method of a data communication system composed of a data transmission device and a data reception device connected via a network,
A first transmission step of transmitting a check packet to the data receiving device in the data communication device;
A first reception step of receiving a check packet from the data transmission device in the data reception device;
A reception notification information generation step of generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device in the data reception device;
A reception notification message for the check packet in the data reception device, a reception notification message generation step for generating a reception notification message including the reception notification information;
A second transmission step of transmitting the generated reception notification message to the data transmission device in the data reception device;
A reception notification message for the check packet transmitted from the data reception device in the data communication device, the reception notification message including reception notification information generated based on shared data shared with the data reception device A second receiving step of receiving
A calculation step of calculating an expected value of the reception notification information based on the shared data shared with the data receiving device in the data communication device;
A comparison step of comparing the reception notification information with an expected value of the reception notification information in the data communication device;
A determination step of determining that a response time of the reception notification message is shorter than a predetermined threshold in the data communication device;
A data communication method comprising: a determination step of determining permission of data transmission to the data reception device based on a comparison result of the comparison step and a determination result of the determination step in the data communication device. In a data transmission device that transmits data,
Transmitting means for transmitting a check packet to the data receiving device;
Receiving means for receiving a reception notification message for the check packet transmitted from the data reception device, the reception notification message including reception notification information generated based on shared data shared with the data reception device; ,
Calculation means for calculating an expected value of the reception notification information based on the shared data shared with the data receiving device;
Comparison means for comparing the reception notification information with an expected value of the reception notification information;
Determining means for determining that a response time of the reception notification message is shorter than a predetermined threshold;
A data transmission device comprising: a determination unit that determines permission of data transmission to the data reception device based on a comparison result of the comparison unit and a determination result of the determination unit. The data transmission device according to claim 3, wherein the transmission unit transmits a check packet to the data reception device a predetermined number of times. The data transmission device according to claim 3, wherein the transmission unit transmits a check packet to the data reception device using TCP (Transport Control Protocol). The data transmission apparatus according to claim 3, wherein the transmission means transmits a check packet to the data reception apparatus using UDP (User Datagram Protocol). The data transmission device is connected to a first network;
The determination means identifies whether the data receiving device is connected to a second network different from the first network based on the comparison result of the comparison means and the determination result of the determination means, and this The data transmitting device according to claim 3, wherein permission of data transmission to the data receiving device is determined based on an identification result. The first network is a LAN (Local Area Network),
The data transmission device according to claim 7, wherein the second network is a WAN (Wide Area Network). In a data transmission method of a data transmission apparatus for transmitting data,
A transmission step of transmitting a check packet to the data receiving device;
A reception step of receiving a reception notification message for the check packet transmitted from the data reception device, the reception notification message including reception notification information generated based on shared data shared with the data reception device; ,
A calculation step of calculating an expected value of the reception notification information based on the shared data shared with the data receiving device;
A comparison step of comparing the reception notification information with an expected value of the reception notification information;
A determination step of determining that a response time of the reception notification message is shorter than a predetermined threshold;
A data transmission method comprising: a determination step of determining permission of data transmission to the data reception device based on a comparison result of the comparison step and a determination result of the determination step. Transmitting means for transmitting a check packet to the data receiving device;
Receiving means for receiving a reception notification message for the check packet transmitted from the data reception device, the reception notification message including reception notification information generated based on shared data shared with the data reception device; A program for controlling a data transmission device comprising:
A calculation step of calculating an expected value of the reception notification information based on the shared data shared with the data receiving device;
A comparison step of comparing the reception notification information with an expected value of the reception notification information;
A determination step of determining that a response time of the reception notification message is shorter than a predetermined threshold;
A program that causes a computer to execute a process including a comparison result of the comparison step and a determination step of determining permission of data transmission to the data reception device based on the determination result of the determination step. In a data receiving apparatus that receives data from a data transmitting apparatus that determines whether to permit data transmission based on reception notification information and response time,
Receiving means for receiving a check packet from the data transmitting device;
Reception notification information generating means for generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device;
A reception notification message for the check packet, a reception notification message generating means for generating a reception notification message including the reception notification information;
A data receiving apparatus comprising: a transmitting means for transmitting the reception notification message to the data transmitting apparatus when the check packet transmitted by the data transmitting apparatus is received by the receiving means. The data receiving apparatus according to claim 11, wherein the receiving unit receives the check packet transmitted a predetermined number of times from the data transmitting apparatus. The data receiving apparatus according to claim 11, wherein the receiving unit receives the check packet transmitted from the data transmitting apparatus using TCP (Transport Control Protocol). The data reception device according to claim 11, wherein the reception unit receives the check packet transmitted from the data transmission device using UDP (User Datagram Protocol). The data transmission device is connected to a first network;
The data receiving device according to claim 11, wherein the data receiving device is connected to a second network different from the first network. The first network is a LAN (Local Area Network),
The data receiving apparatus according to claim 15, wherein the second network is a WAN (Wide Area Network). In the data receiving method of the data receiving apparatus that receives data from the data transmitting apparatus that determines whether to permit data transmission based on the reception notification information and the response time,
A receiving step of receiving a check packet from the data transmitting device;
A reception notification information generating step for generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device;
A reception notification message for the check packet, a reception notification message generating step for generating a reception notification message including the reception notification information;
A data reception method comprising: a transmission step of transmitting the reception notification message to the data transmission device when the check packet transmitted by the data transmission device is received in the processing of the reception step. A program for controlling a data receiving apparatus that receives data from a data transmitting apparatus that determines whether to permit data transmission based on reception notification information and a response time,
A reception notification information generating step for generating reception notification information based on shared data shared on the premise of predetermined processing with the data transmission device;
A reception notification message for a check packet from the data transmission device, a reception notification message generating step for generating a reception notification message including the reception notification information;
A program for causing a computer to execute a process including: a transmission step of transmitting the reception notification message to the data transmission device when the check packet is received from the data transmission device.

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