JP2003023377A - Method and device for removing virus in power line communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for detecting and removing the invasion of virus by detecting the virus to exert an adverse influence upon various kinds of electrical appliances. SOLUTION: In power line communication, the information signal wave component of a received high frequency is separated by a branching filter and next, the separated information signal is compared with various kinds of virus patterns so that the virus can be detected and removed. Further, when the virus is detected, an alarm is raised.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting and removing a virus in power line communication, and more particularly, it has a bad influence on an information signal AC-coupled to a power line outside a home. The present invention relates to a method and an apparatus for detecting and removing invasion of a virus at a house pull-in place of a power line when unnecessary information, that is, a virus is included.

[0002]

2. Description of the Related Art In power line communication, in which information signals are AC-coupled to a power line for communication, an existing power line in a home can be used, so that there is an advantage that no new wiring is required for communication. In the power line communication, the superposition of the information signal on the power line is usually performed in a form in which a modulated wave of information transmitted by a dedicated communication line such as the Internet public network is AC-coupled with a commercial AC power source on a utility pole outside the house. . The information signal fetched from the power line through the home service line is connected to a modem provided in various home electric appliances. Then, this information signal is used for operation of those home electric appliances and Internet information of a personal computer.

[0003]

However, when a virus that adversely affects the information signal AC-coupled to the power line outside the house is included in the house, the power line drawn into the house is usually an ordinary one. As it is a commercial AC power line, virus intrusion is not noticed.

Further, in the conventional power line communication, the power line drawn into the house is connected to various home electric appliances, and the information signal is directly input to the modem corresponding to those products. For this reason, even if a malicious virus is mixed in the information, the virus cannot be detected or removed, and there is a risk that the home electric appliance may malfunction or may be damaged.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an information signal by power line communication when a virus that adversely affects various home electric appliances is included. By detecting the intrusion of a virus, issuing an alarm, and removing the virus.

[0006]

In order to achieve the above object, the present invention first separates and extracts a high frequency information signal wave component superimposed on a power line for power line communication by a demultiplexer and then , Comparing the demodulated signal waveform of the separated information signal with a plurality of virus pattern waveforms registered in advance,
When the demodulated signal waveform of the information signal matches any one of the waveform pattern waveforms registered in advance, it is determined that a virus has entered and the delivery of the received information signal is blocked.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a diagram showing a device configuration in which a virus removal device is installed in the power line communication according to the first embodiment of the present invention. In FIG. 1, a power line that is responsible for power line communication is drawn into the house in a form coupled with a communication line such as an Internet public network by a utility pole outside the house, and is connected to various home electric appliances in the house through a modem. There is. The virus removal device 1 is provided immediately after the power line is drawn into the house through the house drop line, and separates the information signal wave component superimposed on the power line drawn into the house,
After that, the demodulated and reproduced information signal wave is checked in advance with various virus patterns that adversely affect the home electric appliances, the virus is detected, and the virus is removed. It is possible to prevent adverse effects.

FIG. 2 is a diagram showing a virus removing device according to the first embodiment of the present invention. The virus removal device 1 includes a branching filter 11, a virus detection / removal unit 12, and a mixer 13. The demultiplexer 11 is a frequency filter, and has a high-frequency information signal wave component with a frequency of about 400 kilohertz (KHz) superimposed on the power line and a frequency of 10 hertz (H).
z) commercial AC signals are separated from each other. The separated AC signal which is one output is directly input to the mixer 13 through the power line. On the other hand, the other output information signal is input to the virus detection / removal unit 12. The virus detection / removal unit 12 is a unit that detects and removes a virus, and an information signal that is determined not to have a virus risk is output to the mixer 13, and an information signal that is determined to be a virus risk. Virus part is removed and mixer 1
3 is output.

The mixer 13 includes a virus detection / removal unit 12
It is a coupler that AC-couples the information signal from which the virus has been removed by a commercial AC signal. The information signal coupled to the power line is supplied to the electric appliances in the house.

The virus detection / removal unit 12 includes a demodulation circuit 2
1, a memory 22, a virus pattern registration memory 23, a waveform comparator 24, a delay circuit 25, and a selector 26. The information signal from the demultiplexer 11 is branched into two,
One is input to the demodulation circuit 21, and the other is input to one input terminal of the selector 26 via the delay circuit 25. The delay circuit 25 is a circuit that delays the information signal wave for a predetermined time in order to match the processing time for waveform comparison or the like as described later. The demodulation circuit 21 is configured by a bandpass filter or the like that passes low frequency, and demodulates the amplitude-modulated information signal. As a result, the demodulation circuit 21 extracts the demodulated wave of the amplitude-modulated information signal, and the extracted information signal waveform is sequentially input to the demodulated signal memory 22.

The modulated signal wave superimposed on the power line is
For example, after amplitude modulation such as a QPSK signal, a further 4
In some cases, a modulated signal wave that has been subjected to secondary modulation such as phase modulation of a phase is used. In this case, the demodulation circuit 21 first needs to be configured to demodulate the secondary modulated wave with a carrier once and then to extract the demodulated wave of the amplitude-modulated information signal as described above. . On the other hand, various virus waveforms are detected in advance and recorded in the virus pattern registration memory 23 in the form of waveforms.

The waveform comparator 24 compares the waveform read from the demodulated signal memory 22 in which the demodulated wave of the input information is recorded with the virus waveform read from the virus pattern registration memory 23. When the input information signal waveform matches the virus waveform read from the virus pattern registration memory 23, the waveform comparator 24 determines that the input information signal waveform contains a virus, and the information signal is transmitted to the home electric appliances in the home. An instruction signal for preventing transmission is output to the selector 26.

When the selector 26 receives the instruction signal for blocking the transmission of information from the waveform comparator 24, the delay circuit 25.
Transmission of the information signal wave from the mixer to the mixer 13 is stopped. As a result, when the virus detection / removal unit 12 detects the virus pattern waveform included in the information signal as described above,
It prevents the virus from being delivered to the mixer 13.

In this way, the information signal from which the virus wave has been removed is input to the mixer 13, superimposed again on the commercial AC power source, and delivered to each home electric appliance in the house.

Embodiment 2. FIG. 3 shows a virus detection / detection method according to the second embodiment of the present invention for detecting and eliminating virus invasion.
It is a figure which shows the removal part 12. Since the demultiplexer 11 and the mixer 13 in the virus removing device 1 are the same as those in FIG. 1, illustration and description thereof will be omitted. This virus detection / removal unit 1
In power line communication, 2 detects a virus included in an information signal wave by collating it with a predetermined digital data pattern. The virus detection / removal unit 12 according to the second embodiment includes the demodulation circuit 21, the delay circuit 25, and the delay circuit 25 used in the first embodiment.
In addition to the selector 26, the sampling circuit 31, the patterning circuit 32, the demodulation signal memory 33, the virus pattern registration memory 34, and the correlator 35 are included.

The information signal input from the demultiplexer 11 is 2
One is input to the demodulation circuit 21, and the other is input to one input terminal of the selector 26 via the delay circuit 25. The delay circuit 25 is a circuit that delays the information signal wave by a predetermined time in order to match the processing time for waveform comparison described later.

The demodulation circuit 21 is composed of a bandpass filter or the like that passes low frequencies, and demodulates the amplitude-modulated information signal. The sampling circuit 31 is the demodulation circuit 2
The signal wave demodulated by 1 is sampled with a sampling clock having a predetermined cycle and digitized. The patterning circuit 32 converts the individual data digitized by the sampling into bit data of a predetermined bit rate, and further patterns it into a predetermined data length. The patterning to a predetermined data length is performed based on the information included in the head data of the signal information. The converted digital data having a predetermined data length is used for the demodulation signal memory 3
3 is stored and held. On the other hand, the virus pattern registration memory 34 stores and holds various virus patterns as digital data having a predetermined data length.

Further, the correlator 35 is a demodulation signal memory 33.
The digital data pattern read from the virus pattern is compared with the virus pattern of various data lengths read from the virus pattern registration memory 34, and the correlation coefficient is calculated for the similarity. As a result, when the correlation coefficient is larger than the predetermined value, the correlator 35 determines that the information signal contains a virus, and instructs the selector to remove the information signal.

In this way, the information signal wave superimposed on the power line is separated, and the virus is detected by correlating the digitized information signal with various digitized virus patterns to prevent the virus from entering. You can do it.

Embodiment 3. In the first and second embodiments of the present invention, the method of blocking the distribution of the information signal when the virus is detected has been described.
When a virus is detected, an alarm is issued to call your attention,
Alternatively, null information is inserted in the virus portion of the information signal.

FIG. 4 is a diagram showing a virus detection / removal unit for detecting and removing virus invasion according to the third embodiment of the present invention. In FIG. 4, a null data generator 41 and an alarm data generator 42 are added to the virus detection / removal unit of FIG. 2, and other configurations are similar to those of FIG. In addition, the demultiplexer 11 in the virus removal device 1
Since the mixer 13 is the same as that shown in FIG. 1, illustration and description thereof will be omitted. When the waveform comparator 24 detects a virus, it instructs the selector 26 to insert null data or alarm data in the portion of the information signal output from the delay circuit 25 corresponding to the virus. Based on the instruction from the waveform comparator 24, the selector 26 inserts null data or alarm data into the portion of the information signal output from the delay circuit 25 that corresponds to the virus. The information signal in which the null data or the alarm data is inserted is mixed with the power line by the mixer 13 and supplied to each home electric appliance in the house.

[0022]

As described above, according to the present invention,
It is possible to detect the virus by comparing the demodulation waveform obtained by separating the information signal from the power signal with the waveform of the pre-registered virus pattern, and detect whether they match, thereby preventing the distribution of the information signal. . Therefore, the cause of malfunction or failure of the home electric appliances is eliminated, and the security of communication using the power line communication can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a device configuration of power line communication in which a virus removal device according to a first embodiment of the present invention is installed.

FIG. 2 is a diagram showing a virus detection / removal unit in the virus removal device according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a virus detection / removal unit in the virus removal device according to the second embodiment of the present invention.

FIG. 4 is a diagram showing a virus detection / removal unit in a virus removal device according to a third embodiment of the present invention.

[Explanation of symbols]

1. Virus removal device 11 ... duplexer 12 ... Virus detection / removal unit 13 ... Mixer 21 ... Demodulation circuit 22, 33 ... Demodulation signal memory 23, 34 ... Virus pattern registration memory 24 ... Waveform comparator 25 ... Delay circuit 26 ... Selector 31 ... Sampling circuit 35 ... Correlator

Claims (10)

[Claims] 1. A method of removing a virus included in an information signal in power line communication, wherein an information signal received at home is separated from a power line, a demodulated signal waveform of the separated information signal and a plurality of viruses registered in advance in waveform. The pattern waveform is compared, and when the demodulated signal waveform of the information signal matches any of the virus pattern waveforms registered in advance, it is determined that a virus has entered and the delivery of the received information signal is blocked. Characteristic virus removal method. 2. The comparison between the demodulated signal waveform of the information signal and any of the virus pattern waveforms registered in advance is performed by correlating both waveforms, and when the correlation value is a predetermined value or more, The virus removing method according to claim 1, wherein it is determined that the demodulated signal waveform of the information signal matches any one of the waveform pattern waveforms registered in advance. 3. A null signal is inserted in the portion of the information signal when the demodulated signal waveform of the information signal matches any one of the virus pattern waveforms registered in advance. Or the method for removing a virus according to 2. 4. The virus removing method according to claim 1, wherein a virus alarm signal is issued when the demodulated signal waveform of the information signal matches any one of the virus pattern waveforms registered in advance. . 5. The separated demodulated signal waveform is sampled to generate a pattern having a predetermined digital data length, and the plurality of virus patterns are stored as a pattern having a predetermined predetermined digital data length. The method for removing a virus according to claim 1, wherein 6. A device for removing a virus contained in an information signal in power line communication, a demultiplexer for separating an information signal received at home from a power line, and a demodulation means for demodulating the information signal separated by the above. Virus pattern recording means for recording a plurality of virus patterns registered in advance in waveform, comparing means for comparing the demodulated signal waveform demodulated by the demodulating means with the virus pattern waveform, and a mixer for mixing information signals on the power line. In the comparison means, when the demodulated signal waveform of the information signal matches any of the virus pattern waveforms registered in advance, it is determined that a virus has entered, and only the virus signal component is removed. A virus removal device characterized in that an information signal is mixed with a power line by a mixer. 7. The comparator correlates both waveforms, and when the correlation value is equal to or more than a predetermined value, the demodulated signal waveform of the information signal and any of the virus pattern waveforms registered in advance. 7. The virus removing apparatus according to claim 6, wherein it is determined that and match. 8. A null signal generating means for generating a null signal is further provided, and in the null signal generating means, the demodulated signal waveform of the information signal matches any one of the waveform pattern waveforms registered in advance. The virus removal device according to claim 6 or 7, wherein a null signal is inserted into the information signal. 9. The apparatus further comprises virus alarm signal generating means for issuing a virus alarm signal, wherein the virus alarm signal generating means generates a demodulated signal waveform of the information signal and any of the virus pattern waveforms registered in advance in waveform. 8. The virus removing device according to claim 6, wherein a virus alarm signal is inserted into the information signal when they match. 10. A sampling means and a logical information pattern means for sampling the separated demodulated signal waveform, wherein the demodulated signal waveform is sampled by the sampling means and then the logical information pattern means. 7. The virus removing apparatus according to claim 6, wherein the virus pattern recording unit is generated as a pattern having a predetermined digital data length, and the virus pattern recording unit stores the virus pattern in advance as a pattern having a predetermined digital data length.