JP4254562B2 - Specific area confidential information distribution method and confidential information distribution system - Google Patents

Description

  The present invention relates to wireless communication in a specific area limited within a certain area, and more particularly, to a specific area confidential information distribution system that distributes information while maintaining confidentiality for persons in the specific area.

  In recent years, a vast amount of information has been exchanged throughout the world using developed communication technology. There is a lot of secret information that must not be known by anyone other than the communication partner, and as a technique for this purpose, secret communication technology and encryption technology have been developed. In particular, when it is necessary to inform a specific person of confidential information within a specific group, it is required to notify the information only to the specific person while maintaining high confidentiality, so that information distributed by other than the specific person cannot be received. It is important to.

As a method of communication with a specific area (specific person) by wireless communication, in Patent Document 1, a specific notification is provided separately from a simultaneous broadcast channel that notifies a mobile terminal in a specific area within the coverage of a base station to the entire area. A technique for performing communication with a specific mobile terminal in a specific area by setting a channel for transmitting information is disclosed.
Japanese Patent Laid-Open No. 11-220964

  As a method for notifying information while maintaining confidentiality, conventionally, a communication line is fixed, and information is notified by performing encryption processing on the information.

 By fixing the line, when wired communication is used, it is possible to perform communication with better confidentiality than wireless communication. In the case of wireless communication, there is a method of changing the frequency and changing the channel every time information is distributed to fix the line. However, there is a limit to maintaining confidentiality due to restrictions on the frequency band that can be used.

  Further, even if the communication line is fixed, it is difficult to perform communication with confidentiality as compared with the wired case because the electric wave exists everywhere in the range where the electric wave reaches.

 The problem to be solved is to distribute confidential information without increasing the resources used by radio waves.

 1st invention is the confidential information delivery method which delivers the confidential delivery information to the delivery information receiver of a specific area.

Holds delivery information, the information distribution center station to specify a delivery destination of the distribution information, and the previous SL information distribution center station receives the instruction information distributed from, said plurality of three or more to deliver the distribution information base station And a wireless communication network connected with a distribution information receiving device having means for receiving the distribution information from the plurality of base stations.

  The information distribution center station is a time for the distribution information for each base station, which is obtained by dividing the distribution information for each of the plurality of base stations and assigned to the base station, to reach the distribution information receiving device from the plurality of base stations. A base station radio wave arrival time is calculated, and a base station distribution delay time for each base station where the base station distribution information intersects with the distribution information receiving device in synchronization with the base station radio wave arrival time is calculated.

The information distribution center station, said the plurality of base stations, a base station for each encrypted distribution information obtained by encrypting the base station for each distribution information, the distribution start reference time, and the station-based delivery delay time, said plurality A transmission pulse time that the base station modulates during the time determined by the base station encrypted distribution information, and the base station encryption from the plurality of base stations during the time determined by the distribution information receiver The data acquisition time for acquiring the distribution information is distributed.

The plurality of base stations, after waiting for the delivery delay time for each base station from the delivery start reference time , modulates the data capture time and the encrypted delivery information for each base station between the transmission pulse times. And distributed to the distribution information receiving apparatus via a wireless network.

The distribution information receiving apparatus receives the distribution information for each base station from the plurality of base stations at a synchronized time, and demodulates the encrypted distribution information for each base station during the data capture time .

The second invention is a secret information distribution system in a specific area by utilizing the first invention.

Holds delivery information, the information distribution center station to specify a delivery destination of the distribution information, and the previous SL information distribution center station receives the instruction information distributed from, said plurality of three or more to deliver the distribution information base station A secret information distribution system via a wireless communication network in a wireless communication network configured with a distribution information receiving device having means for receiving the distribution information from the plurality of base stations.

  The information distribution center station and the plurality of base stations include means for synchronizing time.

The information distribution center station, the distribution information the divided station-distribution information assigned to the base station for each of the plurality of base stations is the time to reach the distribution information receiving apparatus from the plurality of base stations A means for calculating a radio wave arrival time for each base station; and a base station distribution delay time for each base station where the distribution information for each base station intersects with the distribution information receiving device in synchronization with the radio wave arrival time for each base station Means for encrypting the delivery information for each base station, encrypted encrypted delivery information for each base station, delivery start reference time, delivery delay time for each base station, and the plurality of base stations The transmission pulse time that is modulated during the time determined by the base station encrypted distribution information and the base station encrypted distribution information from the plurality of base stations during the time determined by the distribution information receiving device When importing data And a means to deliver, and.

Said plurality of base stations, from the distribution starting time from the previous SL information distribution center station, after waiting the base station every delivery delay, the said data acquisition time, the a base station for each encrypted distribution information, the And means for modulating the transmission pulse time and distributing it by the distribution information receiving device .

The distribution information receiving device includes means for synchronously receiving the base station distribution information from the plurality of base stations and demodulating the base station encrypted distribution information during the data capture time. .

  FIG. 1 is a configuration diagram of a secret information distribution system in a specific area. In accordance with instructions from the information distribution center station 10 and the information distribution center station 10, a base station 111, a base station 2 12, and a base station 3 13 that distribute information are installed and connected by a wired communication network 1. Further, a specific area A receiving device 14, a specific area B receiving device 15, and a specific area C receiving device 16 that receive distribution of information from each base station are installed and connected by the wireless communication network 2. An information distribution main server is disposed in the information distribution center station 10, and an information distribution server 1, an information distribution server 2, and an information distribution server 3 are installed in the base station 1, the base station 2, and the base station 3, respectively. From these three base stations, confidential information is distributed as radio waves to a specific area designated by the information distribution main server. The number of base stations is determined by a plurality of stations at three or more locations. In this example, the case of the minimum three base stations is shown.

 The information acquirer A, the information acquirer B, and the information acquirer C receive the distribution information in the specific area A receiving device, the specific area B receiving device, and the specific area C receiving device. Information reception may be received in the destination identification area by registering the location of the destination identification area in advance.

Further, τ1 _A , τ2 _A , and τ3 _A indicate distribution delay times at the time of radio wave transmission instructed to each base station from the information distribution center station 10 to the specific area A described later. The delivery delay time will be described later.

 FIG. 2 shows instruction information from the center station to the base station according to the embodiment of the present invention. The instruction information to the base station 1 includes a command signal, a distribution start reference time, a transmission pulse time, distribution destination specifying area information, encrypted distribution information, and division control information. The instruction information to the base station 2 and the base station 3 includes a distribution start reference time, a transmission pulse time, distribution destination specifying area information, and encrypted distribution information. The command signal is composed of an activation signal and data capture time, and the distribution destination specific area information is composed of the identification number of the receiving device and the distribution delay time. The division control information is information indicating that the distribution information is divided when the information amount of the distribution information is large.

Before describing the specific information distribution processing procedure, the distribution delay time, command signal, and transmission pulse time will be described.
1) Delivery delay time The arrival time of radio waves radiated from a base station reaches a receiving device in a specific area varies depending on the distance between the base station and the receiving device. The distribution delay time is information on radio wave radiation time control from the information distribution center station to the base station in order to make radio wave reception at the reception destination the same time. For example, it is calculated by the following method.
I. The arrival time until the radio wave reaches the receiving device is calculated from the distance between the base station and the receiving device. For the base station 1, the time required for transmitting the command signal is also converted.
B. By calculating backward from the arrival time, the time (hereinafter referred to as “delivery delay time”) is calculated from the reference time for starting information delivery at the base station until information is delivered at each base station. If τ1, τ2, and τ3 are the delivery delay times of each base station, the result is as follows.

τ1 = t0 + (t2−t1)
τ2 = t0
τ3 = t0 + (t2−t3)
Here, t1, t2, and t3 are radio wave arrival times converted from the distance between each base station and the delivery destination. In this example, the radio wave arrival time between the base station 2 and the reception destination is minimized. ing. Further, t0 is a processing time that is instructed from the information distribution center station and required for each base station to start distribution from the distribution start reference time.
2) Transmission pulse time A time window for modulating encrypted distribution information in each base station. This is shown together with the distribution information from the base station in FIG. In the base station 1, it is a time for modulating the command signal in addition to the encrypted distribution information and the division control information. In the base station 2 and the base station 3, it is time to modulate the encrypted distribution information. The pulse time can be, for example, several milliseconds to several seconds. The information distribution center station determines the information confidentiality and distribution information. By shortening the transmission pulse time, confidentiality can be improved. The confidentiality will be described later together with the restoration of the distribution information in FIG.
3) Command signal FIG. 3 is a diagram showing a command signal according to an embodiment of the present invention. The command signal is transmitted only from a predetermined base station (base station 1 in the following example), and is composed of a radio wave reception start signal at the distribution destination receiving apparatus and a data capture time for receiving data from the received radio wave. The data capture time is a time for capturing the received information, and the information is captured and demodulated only for a specified time in the received radio wave. The example of FIG. 3 shows a case where a command signal is configured by a combination of a start signal and pulses having a constant pulse width and a constant pulse amplitude, all of which have the same pulse pattern. A predetermined data acquisition time is designated by the combination of the pulse patterns. FIG. 3 shows an example of eight data acquisition times of “1” for the last pulse P4 as a combination of pulse patterns. In the case of pattern 1, the data capture time is TW1. The command signal is transmitted not as encrypted digital information but as an analog pulse shape. In the receiving apparatus, the command signal detects information in an analog manner depending on the presence or absence of a pulse waveform.

 Among the command signals, for the pulse pattern of the data capture time, there is a method of using a variable width pulse in which the pulse width is associated with the data capture time width instead of the same fixed pulse as the start pulse. Further, when receiving at a constant data capture time at all times, it is not necessary to transmit this pulse pattern.

 FIG. 4 is a diagram showing distribution information from the base station according to the embodiment of the present invention. The base station 1 is composed of a command signal, encrypted distribution information, and division control information. Base station 2 and base station 3 are composed of encrypted distribution information. The division control information can be determined by determining, for example, a combination of digital information as control information for indicating a series of information when the distribution information is divided.

 Although the number of divisions depends on the modulation speed, for example, about 10 divisions can be considered as distribution information of about several Mbytes.

FIG. 5 is a diagram showing an information distribution processing procedure according to an embodiment of the present invention.
1) Transmission flow of the information distribution center station S1: In response to an information communication execution request to a specific area, the content of information distribution and the distribution destination are determined. For distribution contents, determine the number of distribution divisions based on the amount of distribution information and confidentiality.

 S2: The radio wave arrival time at the distribution destination receiving device is calculated from the distance between the base station and the distribution destination, and converted into the distribution delay time. The distribution information for each time is encrypted and divided into three for the base station 1, the base station 2, and the base station 3.

S3: The base station 1 encrypts the command signal, the distribution start reference time, the distribution destination specifying area information, the distributed encrypted distribution information and the division control information together, and transmits them through the wired network. The base station 2 and the base station 3 transmit the delivery start reference time, the delivery destination specific area information, and the distributed encrypted delivery information via the wired network.
2) Information reception and information distribution flow at each base station S4: Receive information distributed from the information distribution center station.

S5: The transmitting device of each base station confirms the reference time from the received GPS radio wave, and after waiting for the distribution delay extension time from the distribution start time, radiates the distribution information as a radio wave.
3) Information reception and processing flow in the distribution destination specific area receiving device S6: Information from each base station is received in the specific area. The command signal from the base station 1 and information received based on the division control information are demodulated and decrypted.

  S7: Demodulate the received radio wave during the data capture time, perform decryption, and obtain distribution information.

 FIG. 6 is a block diagram of a base station transmission apparatus according to an embodiment of the present invention. The main server IF 20 that interfaces with the information distribution main server and receives information from the main server, the distribution information that is information from the main server is fetched by the distribution information receiving unit 21, and similarly, the command signal receiving unit 25 receives the command signal The transmission pulse time receiving unit 26 receives the transmission pulse time, and the distribution destination specifying area information receiving unit 28 receives the distribution destination receiving device identification number and the distribution delay time. The command signal receiving unit 25 is provided only in the base station 1, and the base station 1 also receives the division control information in the distribution information receiving unit.

 In the base station 1, the combining unit 22 combines the distribution information and the command signal and sends the combined information to the modulation unit 23. The base station 2 and the base station 3 send distribution information directly to the modulation unit 23. Based on the transmission pulse time received by the transmission pulse time reception unit 26, the modulation unit 23 modulates the output of the coupling unit 22 under the control of the modulation time control unit 27. The modulated distribution information is held in the radio wave transmission unit 24, and the distribution delay time control unit 29 controls the distribution delay time for each base station, and the information distribution specified by the receiving device identification number is received from the radio wave transmission unit 24. Radio waves are radiated toward the specific area receiver.

 As a modulation method, a commonly used method such as FDI (Frequency Division Multiple Access), TDMA (Time Division Multiple Access), or CDMA (Code Division Multiple Access) is used. Details are omitted here. In the base station 1, base station 2, and base station 3, for example, in the case of FDMA, the modulation frequency from each base station is distinguished for each base station, or in the case of CDMA, the spreading code is distinguished for each base station. The modulation method is changed depending on the method.

 With these modulations, in the current technology, each base station transmits information to each information receiving apparatus at an information rate of several Mbps.

 In the clock signal generator 31, the current time of the GPS signal received by the GPS receiver 30, the reference clock from the reference clock generator 32, the time adjustment with the distribution start time of the instruction from the main server, the control of the distribution delay time, Clock control of each part of the transmission apparatus is performed. Details are omitted.

FIG. 7 is a diagram showing base station information distribution timing according to an embodiment of the present invention. From the information distribution server of each base station, the modulated information is radiated as a radio wave after waiting for distribution delay times τ1 _A , τ2 _A , and τ3 _A from the distribution start reference time for area A. Here, the subscript “1 _A ” of τ represents the case of information distribution from the base station 1 to the area A, and the other displays are the same. In addition, for a plurality of areas, for example, distribution to the area B is performed with the distribution delay times τ1 _B , τ2 _B , and τ3 _B from the distribution start reference time for each area. Delivery is performed with delay times τ1 _C , τ2 _C , and τ3 _C.

 FIG. 8 is a block diagram of a receiving apparatus according to an embodiment of the present invention. The radio wave receiving unit 40 interfaces with the base station 1, the base station 2, and the base station 3, and the radio waves from each base station are respectively received by the base station 1-compatible receiving unit 41, the base station 2-compatible receiving unit 42, and the base station 3-compatible. Received by the receiver 43. Receiving a signal from the base station 1 compatible receiving unit 41, the command detecting unit 44 detects the command signal, detects the presence or absence of distribution information from the first activation pulse, and detects the data capture pattern from the subsequent four pulses To do. Each pulse may be detected by detecting the presence or absence of a predetermined constant power pulse. Details are omitted. A data acquisition time corresponding to a predetermined acquisition time is determined by a combination of the second and subsequent four pulse patterns. The data acquisition time setting unit 45 sets the acquisition start time and the time window of the acquisition time, and is controlled by the data acquisition time control unit 46, so that the base station 1 compatible data acquisition unit 47, the base station 2 compatible data acquisition unit 48, the base The station 3 corresponding data capturing unit 49 captures data from each base station within the data capturing time. The data fetched by the base station 1 data fetching unit 47 is demodulated by the base station 1 demodulating unit 50 by a demodulation method corresponding to the modulation method of the base station 1. Similarly, the data captured by the base station 2 compatible data capturing unit 48 and the base station 3 compatible data capturing unit 49 are demodulated by the base station 2 compatible demodulating unit 51 and the base station 3 compatible demodulating unit 52 using the corresponding demodulation methods. To do. The data demodulated by each base station demodulation unit is sent to the data synthesis unit 53, the data from each base station is synthesized, and the encryption / decryption unit 54 performs decryption and decryption to obtain information.

 FIG. 9 is a diagram illustrating reception data capture according to an embodiment of the present invention. The data capture time determined by the pulse pattern is set from the command signal received and detected by the base station 1, the last pulse of the pulse pattern is activated, and the data from each base station is captured during the data capture time.

FIG. 10 is a diagram showing restoration of receiving device distribution information according to an embodiment of the present invention. In the specific area A, the reception times by the distribution delay time control coincide with each other, so that the distribution information can be received within a certain time window. On the other hand, in the area specific area N other than the specific area A, the distribution delay times τ1 _A , τ2 _A , and τ3 _A for the specific area A are transmitted to the specific area N due to the difference in radio wave arrival time between the specific area A and the area N. Since there is a difference in the reception time of the radiated radio wave, information restoration is impossible within a fixed time window in the specific area N.

 Regarding secrecy, the shorter the time window of information demodulated to synchronize data from three locations during a certain data acquisition time (the shorter the transmission pulse time), the more difficult it is to achieve synchronization.

 Also, in order to intercept radio waves in areas other than a specific area, it is necessary to increase the time window to receive distribution information, and to match the encryption algorithm of the encrypted information. Restoration becomes difficult. Even if the encryption algorithm can be matched, the shorter the transmission pulse time, the higher the probability that information other than the target data from the three target locations will be included during the data capture time, and the target from the three locations It becomes difficult to restore the information. Thus, the confidentiality can be controlled by controlling the transmission pulse time.

 As for the position of receiving confidential information in the specific area, it is only necessary that the information distribution center station can identify the position of the information receiver as described above. Therefore, the information receiver may be a mobile station instead of a fixed position. In this case, the information acquirer acquires his / her position information from the GPS, registers it in advance, registers the position by means of communication with the information distribution center station using the identification ID, and receives the distribution information in the specific area of the destination. To do.

It is a secret information distribution system block diagram in a specific area. It is a figure which shows the instruction information from the center station of one Embodiment of this invention to a base station. It is a figure which shows the command signal of one Embodiment of this invention. It is a figure which shows the delivery information from the base station of one Embodiment of this invention. It is a figure which shows the information delivery processing procedure of one Embodiment of this invention. It is a base station transmission apparatus block block diagram of one Embodiment of this invention. It is a figure which shows the base station information delivery timing of one Embodiment of this invention. It is a receiver block block diagram of one Embodiment of this invention. It is a figure which shows reception data capture of one Embodiment of this invention. It is a figure which shows decompression | restoration of the receiver delivery information of one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wired communication network 2 Wireless communication network 10 Information distribution center station (information distribution main server)
11 Base station 1 (information distribution server 1)
12 Base station 2 (information distribution server 2)
13 Base station 3 (information distribution server 3)
14 Specific area A receiver (information acquirer A)
15 Specific area B receiver (information acquirer B)
16 Specific area C receiver (information acquirer C)
20 Main server IF
DESCRIPTION OF SYMBOLS 21 Distribution information receiving part 22 Combining part 23 Modulating part 24 Radio wave transmitting part 25 Command signal receiving part 26 Transmission pulse time receiving part 27 Modulation time control part 28 Distribution specific area information receiving part 29 Distribution delay time control part 30 GPS receiving part (base Bureau)
31 Clock signal generator (base station)
32 Reference clock generator (base station)
DESCRIPTION OF SYMBOLS 40 Radio wave reception part 41 Base station 1 corresponding | compatible receiving part 42 Base station 2 corresponding | compatible receiving part 43 Base station 3 corresponding | compatible receiving part 44 Command detection part 45 Data acquisition time setting part 46 Data acquisition time control part 47 Base station 1 corresponding | compatible data acquisition part 48 Base station 2 compatible data capture unit 49 Base station 3 compatible data capture unit 50 Base station 1 compatible demodulator 51 Base station 2 compatible demodulator 52 Base station 3 compatible demodulator 53 Data composition unit 54 Encryption / decryption unit 55 GPS reception unit (reception) apparatus)
56 Clock signal generator (receiver)
57 Reference clock generator (receiver)

Claims (2)

An information distribution center station that holds distribution information and designates a distribution destination of the distribution information;
Receiving the instruction information distribution from the previous SL information distribution center station, a plurality of base stations more than three of distributing the distribution information,
A secret information distribution method in a wireless communication network configured with a distribution information receiving device having means for receiving the distribution information from the plurality of base stations,
The information distribution center station is a time for the distribution information for each base station, which is obtained by dividing the distribution information for each of the plurality of base stations and assigned to the base station, to reach the distribution information receiving device from the plurality of base stations. Calculate the radio wave arrival time for each base station,
The base station distribution delay time is calculated for each base station where the base station distribution information intersects with the distribution information receiving device synchronously from the base station radio wave arrival time,
The base station encrypted distribution information obtained by encrypting the base station distribution information, the distribution start reference time, the base station distribution delay time, and the base stations Data capture for capturing the transmission pulse time for modulating the encrypted delivery information for each base station and the encrypted delivery information for each base station from the plurality of base stations during the time set by the delivery information receiving apparatus Time, and deliver
The plurality of base stations wait for the delivery delay time for each base station from the delivery start reference time, and then modulate the data capture time and the encrypted delivery information for each base station between the transmission pulse times. To the distribution information receiving device via a wireless network,
The distribution information receiving apparatus receives the distribution information for each base station from the plurality of base stations at a synchronized time, and demodulates the encrypted distribution information for each base station during the data capture time. Secret information distribution method. An information distribution center station that holds distribution information and designates a distribution destination of the distribution information;
In response to an information distribution instruction from the information distribution center station, a plurality of three or more base stations that distribute the distribution information;
A secret information distribution system via a wireless communication network in a wireless communication network configured with a distribution information receiving device having means for receiving the distribution information from the plurality of base stations,
The information distribution center station and the plurality of base stations comprise means for synchronizing time,
The information distribution center station
The base station radio wave arrival time, which is the time for the base station distribution information that is allocated to the base station by dividing the distribution information for each of the plurality of base stations, is the time for the base station to reach the distribution information receiving device. Means for calculating;
Means for calculating a base station delivery delay time for each base station where the base station delivery information intersects with the delivery information receiving device synchronously from the base station radio wave arrival time;
Means for encrypting the distribution information for each base station;
Modulation between the encrypted base station encrypted distribution information, the distribution start reference time, the base station distribution delay time, and the time when the plurality of base stations set the base station encrypted distribution information Means for delivering the transmission pulse time to be transmitted, and the data capture time for capturing the encrypted distribution information for each base station from the plurality of base stations during the time determined by the distribution information receiving device,
The plurality of base stations are
After waiting for the delivery delay time for each base station from the delivery start time from the information delivery center station, the data capture time and the encrypted delivery information for each base station are modulated between the transmission pulse times. Means for distributing by the distribution information receiving device;
The delivery information receiving device
Means for synchronously receiving the base station distribution information from the plurality of base stations, and demodulating the base station encrypted distribution information during the data capture time;
A secret information distribution system characterized by comprising:

Images