JP6341878B2 - Wireless terminal and information leakage prevention system - Google Patents

Description

  The present invention relates to a wireless terminal and an information leakage prevention system for preventing correct information from leaking to a third party.

  Conventionally, in a signal transmission / reception system that collects information wirelessly from a terminal such as a sensor and performs analysis and the like, when wirelessly transmitting information detected by the sensor, the wireless signal (transmission information) is wiretapped to a third party. There was a risk of abuse.

  Therefore, in order to prevent such a situation, the information detected by the wireless terminal is encrypted and transmitted by itself, and the contents can be concealed even if the wireless signal is intercepted. A method of randomly inserting and disturbing the correctness of information is performed (for example, see Patent Document 1).

JP 2006-246166 A

  However, in order to perform encryption processing and dummy signal insertion according to the prior art in the wireless terminal itself such as a sensor, the wireless terminal itself must have specifications that can perform calculation processing for encryption or random number generation, Furthermore, since a module for encryption and random number generation is separately required, these technologies cannot be used with a simple wireless terminal with a small amount of computing resources. Therefore, there has been a problem that such information leakage prevention measures are limited only to the case where a wireless terminal having a calculation resource capable of encryption processing is used.

  An object of the present invention made in view of such circumstances is to provide a wireless terminal and an information leakage prevention system capable of substantially preventing eavesdropping and misuse of transmission information with simple processing without requiring an additional module. There is.

To solve the above problems, a first aspect of the radio terminal according to the present invention, a detection signal generator for generating a detection signal by detecting a predetermined state, delimit a detection time at regular time intervals, the current A pseudo detection signal generating unit that generates a pseudo detection signal obtained by changing the detection signal in the time interval by a calculation process with the detection signal in the previous time interval, and a transmission unit that transmits the pseudo detection signal . The pseudo detection signal generation unit divides the certain time interval into a first time and a second time, and outputs the detection signal in the second time to the first time within the previous time interval. by changing the processing of the detection signal in, it characterized that you generate the pseudo detection signal. In addition, a second aspect of the wireless terminal according to the present invention includes a detection signal generation unit that detects a predetermined state and generates a detection signal, and a detection time divided by a plurality of time intervals of different lengths, A pseudo detection signal generation unit that generates a pseudo detection signal obtained by changing the detection signal in the interval by a calculation process with the detection signal in the previous time interval, and a transmission unit that transmits the pseudo detection signal. The detection signal generation unit generates the pseudo detection signal by changing a detection signal within a long time interval among the time intervals by an arithmetic process with the detection signal within a short time interval. It is characterized by.

  In order to solve the above-mentioned problem, an information leakage prevention system according to the present invention is an information leakage prevention system comprising the above wireless terminal and a signal receiving device that receives a signal from the wireless terminal, wherein the signal The receiving device includes: a receiving unit that receives the pseudo detection signal from the wireless terminal; a storage unit that stores a rule of arithmetic processing in the pseudo detection signal generation unit; and a rule of the arithmetic processing stored in the storage unit. And a detection signal extraction unit that extracts a true detection signal from the pseudo detection signal.

  According to the present invention, it is possible to effectively prevent eavesdropping and misuse of transmission information by a simple process even in a wireless terminal such as a sensor having a small amount of computing resources.

It is a block diagram which shows the structural example of the information leakage prevention system which concerns on one Embodiment of this invention. It is a block diagram which shows the structural example of the radio | wireless terminal which concerns on one Embodiment of this invention. It is a figure explaining the detection by the radio | wireless terminal which concerns on one Embodiment of this invention. It is a figure which shows the example of the detection signal which the radio | wireless terminal which concerns on one Embodiment of this invention produces | generates. It is a block diagram which shows the structural example of the signal receiver which concerns on one Embodiment of this invention. It is a figure explaining the example of a production | generation of the pseudo | simulation detection signal by the radio | wireless terminal which concerns on the 1st Embodiment of this invention. It is a figure explaining the example of a production | generation of the false detection signal by the radio | wireless terminal which concerns on the 2nd Embodiment of this invention. It is a figure explaining the example of a production | generation of the false detection signal by the radio | wireless terminal which concerns on the 3rd Embodiment of this invention.

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

  FIG. 1 is a block diagram showing a configuration example of an information leakage prevention system according to an embodiment of the present invention. In this example, the information leakage prevention system 1 includes one or more wireless terminals 11 (11-1 to 11-N) and a signal receiving device 12. Further, as shown in FIG. 1, the information leakage prevention system 1 may include an analysis processing device 13.

  The wireless terminal 11 is a terminal having a detection function such as a sensor, processes the detection signal as described later, generates a pseudo detection signal, and transmits the signal reception device 12 wirelessly.

  The signal receiving device 12 transmits the pseudo detection signal received from the wireless terminal 11 to the analysis processing device (server) 13 via a network such as the Internet.

  The analysis processing device 13 extracts a detection signal from the pseudo detection signal received from the signal reception device 12, and analyzes the detection signal.

  FIG. 2 is a block diagram illustrating a configuration example of the wireless terminal 11 according to an embodiment of the present invention. In the example illustrated in FIG. 2, the wireless terminal 11 includes a detection signal generation unit 111, a pseudo detection signal generation unit 112, and a transmission unit 113.

  When the detection signal generation unit 111 detects a predetermined state (for example, whether or not a person exists), the detection signal generation unit 111 outputs a detection signal indicating detection to the pseudo detection signal generation unit 112.

  In the present embodiment, a case where the wireless terminal 11 is a human sensor that detects the presence or absence of a person will be described as an example. FIG. 3 is a diagram illustrating detection of the presence / absence of a person by the wireless terminal 11. In this case, the detection signal generation unit 111 detects a person who has entered the sensor detection area using infrared rays, ultrasonic waves, visible light, or the like. For example, when one person enters the sensor detection area, the wireless terminal 11 creates a signal indicating that, and when two persons enter the sensor detection area, the wireless terminal 11 enters the sensor detection area. Detect the number of people.

  FIG. 4 is a diagram illustrating an example of a detection signal generated by the detection signal generation unit 111. As an example of the detection signal, the number of people detected in the sensor detection area is represented by a rectangular signal as shown in FIG. 4A, or a differential signal obtained by differentiating the rectangular signal as shown in FIG. 4B. It can be expressed. When the detection signal is wirelessly transmitted to the signal receiving device 12, the detection signal transmitted from the wireless terminal 11 can be intercepted by a malicious third party. In this case, if the detection signal detection signal as shown in FIG. 4 is wirelessly transmitted as it is, a third party who intercepts the detection signal can know the content of the information, that is, how many people are in the sensor detection area, There is a risk that the information will be wiretapped or misused.

  Therefore, the pseudo detection signal generation unit 112 divides the detection time by a predetermined time interval T in order to prevent correct detection information (such as absence time and number of people) from being accurately grasped by a third party. A pseudo detection signal is generated by changing the detection signal of the interval by calculation processing (arithmetic processing) with the detection signal of the previous (past) time interval, and is output to the transmission unit 113. Thereby, even if a signal is intercepted, the third party cannot obtain a true detection signal, and can substantially prevent eavesdropping and misuse. A specific method for generating the pseudo detection signal will be described later.

  The transmission unit 113 wirelessly transmits the pseudo detection signal input from the pseudo detection signal generation unit 112 to the signal reception device 12. Specifically, the detection time may be divided into predetermined time intervals T, and the detection signals within the time interval T may be transmitted together, or the detection signals may be transmitted as needed in real time.

  FIG. 5 is a block diagram illustrating a configuration example of the signal reception device 12 according to an embodiment of the present invention. In this example, the signal reception device 12 includes a reception unit 121, a storage unit 122, and a detection signal extraction unit 123.

  The reception unit 121 wirelessly receives the pseudo detection signal from the wireless terminal 11 and outputs the pseudo detection signal to the detection signal extraction unit 123.

  The storage unit 122 stores in advance rules for arithmetic processing in the pseudo detection signal generation unit 112 of the wireless terminal 11. The rules for the calculation process include all information (time interval T, calculation expression, etc.) necessary for the calculation process.

  The detection signal extraction unit 123 extracts a true detection signal from the pseudo detection signal received by the reception unit 121 based on the calculation processing rules stored in the storage unit 122.

(First embodiment)
Next, a generation example of a pseudo detection signal by the wireless terminal 11 according to the first embodiment will be described. In the first embodiment, the pseudo detection signal generation unit 112 divides the detection time by a predetermined time interval T while the detection signal generation unit 111 performs the detection operation, and sets each time interval to T ₁ , T ₂ , ···, T _k, ···, and T _n. Then, a pseudo detection signal is generated by changing the detection signal in the current time interval T _k by arithmetic processing with the detection signal in the previous time interval T _k−1 . The length of the time interval T may be several minutes, and may be appropriately selected depending on the purpose, application, number and density of detection signals, such as several seconds, several hours, several days. A specific example of this processing is shown in FIG.

6A and 6B are diagrams for explaining an example of generation of a pseudo detection signal by the wireless terminal 11 according to the first embodiment. FIG. 6A shows a detection signal, and FIGS. 6B and 6C show pseudo detection. The signal is shown. In FIG. 6 (a), is generated detection signal for the presence of human in the time interval T ₁ and T _3, the detection signal because there is no human in the time interval T ₂ are remains zero. If the detection signal shown in FIG. 6A is transmitted as it is, information on how many people existed in the time zone corresponding to the time intervals T ₁ and T ₃ and the time interval T ₂ . Information that there is no person in the corresponding time zone is known to a third party who intercepted the radio signal.

  Therefore, the pseudo detection signal generation unit 112, in a predetermined time interval, when a predetermined time has passed while the detection signal is zero, the previous (past) detection signal detected at the current time interval. A new detection signal is generated by combining the detection signals detected at time intervals.

For example, as shown in FIG. 6B, when the detection signal is zero from the start of the time area of the time interval T ₂ until the time M elapses, at the timing when the time M elapses, the time interval All or any part of the signal detected at T ₁ is combined with the detection signal at time interval T ₂ . Note that although addition is performed in this example, any calculation process of addition, subtraction, multiplication, and division may be performed, or these calculation processes may be combined. In this way, the third party who intercepts a signal transmitted as information time interval T _2, actually to recognize as information there are people in the time zone of the time interval T ₂ that no one, the true information It is impossible to grasp and correct information leakage can be prevented.

  The signal receiving device 12 or the analysis processing device 13 that receives the detection signal stores a predetermined time interval T and time M in the storage unit in advance. This can be performed when the wireless terminal 11 is installed, or by the user changing the setting as appropriate. Then, since the signal receiving device 12 or the analysis processing device 13 can identify the signal added at the time M, only the true detection information can be extracted from the received signal. Even if the actual detection signal and the signal to be added overlap after time M, the true detection signal is obtained by subtracting the added signal based on the information of the time interval T and time M shared in advance. I can grasp it.

  In the example of FIG. 6, the signal detected at the previous time interval is simply repeated, but the detection signal at the nth previous time interval, such as the previous two or three previous time intervals, is used for the calculation. You may do it. Moreover, it is good also as arbitrary time intervals (for example, from 5 minutes before to 10 minutes before) when the last signal was detected. In addition, the time interval for collecting signals used for the calculation may be changed according to a certain rule, such as n + 2, n + 2, n + 1, and so on. Still further, the detection signals at a plurality of time intervals may be arithmetically processed, such as using a signal obtained by superimposing the n-th previous detection signal and the (n + 1) -th previous detection signal.

  In addition to the rectangular signal, the form of the detection signal and the pseudo detection signal may be a signal obtained by differentiating the rectangular signal as shown in FIG. 6C, and can be applied to various signal forms.

(Second Embodiment)
Next, a generation example of a pseudo detection signal by the wireless terminal 11 according to the second embodiment will be described. Since the wireless terminal 11 according to the second embodiment is different from the wireless terminal 11 according to the first embodiment only in the processing of the pseudo detection signal generation unit 112, the description of the other is omitted.

In the first embodiment, the detection signal detected at the previous time interval T is used for the arithmetic processing. However, the pseudo detection signal generation unit 112 of the second embodiment uses the time interval T for the arithmetic processing. Is divided into a signal monitoring time T _A (first time) for monitoring and recording the signal and a signal reflection time T _B (second time) for reflecting the signal used for the arithmetic processing. Then, the pseudo detection signal is generated by changing the detection signal at the signal reflection time T _B by a calculation process with the detection signal at the signal monitoring time T _A within the previous time interval. A specific example of this processing is shown in FIG.

  7A and 7B are diagrams for explaining an example of generation of a pseudo detection signal by the wireless terminal 11 according to the second embodiment. FIG. 7A shows a detection signal, and FIG. 7B shows a pseudo detection signal. ing. In addition, the squares in the figure schematically represent the sampling interval of the detection processing by the wireless terminal 11 and the height schematically represents the signal value.

Pseudo detection signal generation unit 112 of the second embodiment, reflecting the detection signal is monitored in the time interval T ₁ at signal monitoring time T _A, the time period corresponding to the signal reflection time T _B of the time interval T ₂ ( For example, add). If the detection signal is zero at the signal monitoring time T _{A as} in the time interval T ₂ in FIG. 7A, the signal zero may be repeated, or the time interval T _{3 in} FIG. 7B. As shown, the signal monitored at the time interval T ₁ may be reflected again until a new signal is detected at the next signal monitoring time T _A. Further, similarly to the first embodiment, it may be repeated according to a certain rule, or a calculation process may be performed by combining a plurality of signals.

Similarly, if the detected signal by the signal reflection time T _B is not zero, a detection signal of the signal reflection time T _B, a pseudo detection signal by combining the detection signals of the signal monitoring time T _A in the previous time interval Generate. For example, as shown in time interval T ₃ in FIG. 7 (b), obtained by adding the two signals and a pseudo detection signal. Note that the rules for the arithmetic processing (time interval T, signal monitoring time T _A , signal reflection time T _B , and arithmetic expression) may be changed as appropriate in order to make it difficult for a third party to decipher.

(Third embodiment)
Next, a generation example of a pseudo detection signal by the wireless terminal 11 according to the third embodiment will be described. Since the wireless terminal 11 according to the third embodiment is different from the wireless terminal 11 according to the first embodiment only in the processing of the pseudo detection signal generation unit 112, the description of the others is omitted.

  In the first embodiment and the second embodiment, the length of the time interval T that divides the detection time is constant, but the pseudo detection signal generation unit 112 of the third embodiment uses a time under a certain rule. The interval T is set to a plurality of different lengths. Then, the pseudo detection signal is generated by changing the detection signal in the long time interval among the time intervals having different lengths by the arithmetic processing with the detection signal in the short time interval. A specific example of this processing is shown in FIG.

  FIGS. 8A and 8B are diagrams for explaining a modification example of the detection signal by the wireless terminal 11 according to the third embodiment. FIG. 8A shows the detection signal and FIG. 8B shows the pseudo detection signal. Yes. In addition, the squares in the figure schematically represent the sampling interval of the detection processing by the wireless terminal 11 and the height schematically represents the signal value.

For example, as illustrated in FIG. 8, the pseudo detection signal generation unit 112 according to the third embodiment sets the time intervals T ₁ and T ₃ to the same length (time X) in the time intervals T _{1 to} T ₄ . _Let T ₂ and T ₄ be the same length (time Y), then repeat the time interval T _n . Then, the lengths of the time intervals T ₁ and T ₂ are different, and the lengths of the time intervals T ₃ and T ₄ are also different. Further, more complicatedly, the length of the time interval may be three or more.

If the length of the time interval T _2n is longer than the length of the time interval T _2n-1 (i.e., the time X <time Y), the pseudo detection signal generation unit 112, a detection signal of the time interval T _2n, A pseudo detection signal having a time interval T _2n is generated in combination with the detection signal having a previous time interval T _2n−1 . The time position where the detection signal of the time interval T _2n-1 is combined may be an arbitrary position of the time interval T _2n .

  The signal receiving device 12 or the analysis processing device 13 determines the time X, Y and calculation processing rules in advance with the wireless terminal 11 so that the signal receiving device 12 or the analysis processing device 13 extracts the detection signal. can do. Note that the rules (time X, Y, and arithmetic expression) of the arithmetic processing may be changed as appropriate in order to make it difficult for a third party to decipher.

  As described in the first to third embodiments, the wireless terminal 11 generates a pseudo detection signal by changing the detection signal by the pseudo detection signal generation unit 112. Since the signal used for the calculation is a detection signal within the previous time interval, it naturally changes regardless of a random number generator or the like. Therefore, according to the present invention, it is possible to prevent eavesdropping / abuse effectively by preventing a third party from grasping correct information by simple arithmetic processing.

  In addition, the signal reception device 12 previously determines a rule for arithmetic processing with the wireless terminal 11, and stores the rule for arithmetic processing in the storage unit 122. In this way, by arranging the rules of arithmetic processing between the wireless terminal 11 and the signal receiving device 12, the content of the true detection signal is kept secret from a third party, and the signal receiving device 12 A detection signal can be extracted. Similarly, in the analysis processing device 13, the true detection signal can be extracted by storing the rules of the arithmetic processing.

  Further, in the examples shown in the first to third embodiments, the arithmetic processing is addition, but the arithmetic processing may be subtraction, multiplication, or division. Alternatively, a plurality of these operations may be combined. Thereby, the variation of a signal increases and the prediction and analysis by a third party can be made difficult.

  Although the above embodiment has been described as a representative example, it will be apparent to those skilled in the art that many changes and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited by the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, a plurality of constituent blocks described in the embodiments can be combined into one, or one constituent block can be divided.

DESCRIPTION OF SYMBOLS 1 Information leakage prevention system 11 Wireless terminal 12 Signal receiving apparatus 13 Analysis processing apparatus 111 Detection signal generation part 112 Pseudo detection signal generation part 113 Transmission part 121 Reception part 122 Storage part 123 Detection signal extraction part

Claims (4)

A detection signal generator for detecting a predetermined state and generating a detection signal;
Separate detection time at regular time intervals, a pseudo detection signal generator for generating a pseudo detection signal changed by the arithmetic processor of the previous detection signal in the time interval detection signal in the current time interval,
A transmission unit for transmitting the pseudo detection signal;
Equipped with a,
The pseudo detection signal generation unit divides the certain time interval into a first time and a second time, and outputs the detection signal in the second time to the first time within the previous time interval. by changing the processing of the detection signal in the wireless terminal characterized that you generate the pseudo detection signal. A detection signal generator for detecting a predetermined state and generating a detection signal;
A pseudo detection signal generation unit that generates a pseudo detection signal by dividing a detection time by a plurality of time intervals of different lengths and changing a detection signal in the current time interval by a calculation process with the detection signal in the previous time interval; ,
A transmission unit for transmitting the pseudo detection signal;
With
The pseudo detection signal generating section, of the time interval, the detection signal in the long time intervals, by changing the processing of the detection signal in short time intervals, generates the pseudo detection signal A wireless terminal. In the wireless terminal according to claim 1 or 2 ,
The pseudo detection signal generation unit generates the pseudo detection signal by at least one arithmetic process of addition, subtraction, multiplication, and division of a detection signal of a current time interval and a detection signal of a previous time interval. A wireless terminal characterized by An information leakage prevention system comprising: the wireless terminal according to any one of claims 1 to 3 ; and a signal receiving device that receives a signal from the wireless terminal,
The signal receiving device is:
A receiver that receives the pseudo detection signal from the wireless terminal;
A storage unit for storing rules of arithmetic processing in the pseudo detection signal generation unit;
A detection signal extraction unit that extracts a true detection signal from the pseudo detection signal based on the rules of the arithmetic processing stored in the storage unit;
An information leakage prevention system comprising:

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