CN110290085B

CN110290085B - Data ferrying method and system based on network isolation condition

Info

Publication number: CN110290085B
Application number: CN201910746478.1A
Authority: CN
Inventors: 梁用语; 杨国正; 刘京菊; 戚兰兰; 闫雪虎; 钟晓峰
Original assignee: National University of Defense Technology
Current assignee: National University of Defense Technology
Priority date: 2019-08-14
Filing date: 2019-08-14
Publication date: 2020-05-29
Anticipated expiration: 2039-08-14
Also published as: CN110290085A

Abstract

The invention provides a data ferrying method and a data ferrying system based on a network isolation condition, wherein a power transmission line or a power supply line is used as a transmission medium, the scheme adopts a data transmission technical scheme under the network isolation condition that signals are transmitted by using current disturbance of an alternating current power supply line of computer equipment, a computer isolated by a network can still transmit data to the outside, a power transmission line current signal capturing device is realized, the device can be used for capturing the magnitude of a current signal of the power transmission line, and the technical scheme of data modulation and demodulation is used for modulating the data into the current of the computer power supply line and can be captured and demodulated. Thereby finally realizing the transmission process of the file. The limitation of network isolation is effectively broken through, and ferry communication of data is realized; the problem that the conventional ferry communication means is easy to monitor and find is solved; thereby enabling a longer transmission distance to be achieved at a lower cost.

Description

Data ferrying method and system based on network isolation condition

Technical Field

The invention belongs to the field of data transmission, and particularly relates to a data ferrying method and system based on a network isolation condition.

Background

At present, the data transmission technology for realizing the data transmission between two devices can be mainly divided into two types, one type is a conventional method: through IP networks (wired and wireless), USB interface transmission, serial port transmission, etc. Another class is unconventional: video (image) ferrying, electromagnetic leakage content restoration, and the like.

(1) IP network (Wired and wireless)

The most common way of data interaction between computer devices is through an IP network. IP is an abbreviation of internet protocol, and means "protocol for interconnection between networks", that is, a protocol designed for communication between computer networks. In the internet, it is a set of rules that enable all computer networks connected to the network to communicate with each other, defining rules that computers should follow when communicating over the internet. Any vendor of computer systems, while complying with the IP protocol, can communicate with the internet. Network systems and devices such as ethernet networks, packet switching networks, etc. produced by various manufacturers cannot communicate with each other, and the main reason for the failure is because the formats of basic units (referred to as "frames" in the art) of data transmitted by the network systems and devices are different.

The IP protocol is actually a set of protocol software composed of software programs, and it uniformly converts various "frames" into "IP datagram" format, which is a most important feature of the internet, so that all kinds of computers can be intercommunicated on the internet, i.e. it has "openness" feature.

(2) USB interface transmission

USB (universal Serial bus) is known as universal Serial bus, which is created to solve the plug and play requirement and supports hot plug. The USB is a structure of a master-slave mode, the USB bus belongs to a polling type bus, and a host control port initializes all data transmission. Each bus action transfers up to three packets including Token (Token), Data (Data), and contact (handwake). According to the established principle before transmission, at the beginning of each transmission, the host sends a USB packet describing the type, direction, USB device address and terminal number of the transmission action, and this packet is usually called token packet (token packet). The USB device fetches the data belonging to itself from the appropriate location of the decoded data packet. The data transfer direction is either from host to device or device to host.

At the beginning of transmission, the transmission direction of the data is marked by a marker packet, and then the transmitting end starts sending a data packet containing information or indicating that there is no data transfer. The receiving end also sends a handshake packet indicating whether the transmission is successful. USB data transmission between a sending end and a receiving end can be considered as a channel between ports of a host and a device. The USB has a special channel-the default control channel-which belongs to the message channel and exists upon device activation, thus providing an entry for device setup, status inquiry and input control information.

(3) Serial port transmission

A Serial port, also called a Serial communication interface (generally referred to as a COM interface), is an extended interface that uses a Serial communication method. The appearance of serial ports was around 1980, and the data transmission rate was 115kbps to 230 kbps. The initial serial port is used for connecting a mouse, an external Modem, an old-fashioned camera, a tablet and other devices. The serial port can also be applied to interconnection and data transmission between two computers (or equipment). Because serial ports (COM) do not support hot plug and low transmission rate, some new main boards and most portable computers have started to cancel the interfaces. At present, serial ports are mostly used in industrial control and measurement equipment and part of communication equipment.

Common are RS-232 for general computer applications (using 25-pin or 9-pin connectors) and half-duplex RS-485 and full-duplex RS-422 for industrial computer applications.

Serial Interface means data are transmitted in sequence bit by bit, and features simple communication line, bidirectional communication via one pair of transmission lines and use of telephone line, resulting in low cost, especially suitable for long-distance communication but low transmission speed. The distance of the serial communication may range from a few meters to several kilometers. Serial communication can be further divided into simplex, half-duplex and full-duplex depending on the direction of information transfer.

(4) Video (image) ferry

The screen is prohibited from being shot, so that screen leakage can be prevented to a certain extent, however, with the increasing of intelligent devices with the functions of shooting and shooting, the fact that important documents of a company are leaked out through screen shooting also becomes a great hidden danger of the company. The prevention and control of the secret divulgence caused by photographing are less in the market.

(5) Electromagnetic leakage content restoration

In 1985, the Dutch student Van Eck (Van Eck) published a paper in Computer & Security, which introduced the principle of receiving Computer displays from a distance, and he used only $ 15 components and a black and white television, and disclosed the electromagnetic leakage risk of CRT displays of computers for the first time. Therefore, this phenomenon is called "Van ekhacking". This effort led to the TEMPEST project on electromagnetic leakage studies that has long been of interest in the united states. As early as the 50 s of the twentieth century, the U.S. government began to notice that electromagnetic wave emissions could be captured causing a compromise. If the transmission comes from a cryptographic device, the resulting compromise would be fatal. In 2003, a paper of doctor Kuhn (Kuhn) of cambridge university teaches a computer electromagnetic leakage principle and a receiving method, and provides a method for acquiring computer sensitive information through active attack. The Cohen doctor hides the intentionally stolen signal into the normally displayed video of the computer display by using the electromagnetic wave leakage emission principle, and transmits the sensitive information by virtue of the strong emission of the electromagnetic wave of the video of the display. The software algorithm skillfully hides and embeds the sensitive information into the video of the computer display, so that the sensitive information is not easy to observe by human eyes, and the receiver can obtain the hidden electromagnetic wave information at a long distance with high quality. The thieves can make the software hiding algorithm into a trojan horse to be implanted into the attacked computers, attack the computers which are not networked, and have strong concealment.

In summary, the prior art has the following disadvantages:

(1) in an environment with high sensitivity, interfaces such as a conventional network port, a USB port and a serial port can be closed, so that the conventional interfaces are hardly possible to access a computer and transmit data;

(2) some servers are installed in racks, have no dedicated display, and are connected to be used only when needed, so that neither video (image) ferry nor electromagnetic leakage content restoration in the non-conventional method can be used.

Disclosure of Invention

In order to solve the technical problems, the invention provides a data ferrying method and a data ferrying system based on a network isolation condition, which utilize a data transmission technology of transmitting signals by using current disturbance of a power supply line of computer equipment to realize data communication under the network isolation condition.

According to an embodiment of the present invention, the present invention provides a data ferry method based on a network isolation condition, which uses a transmission line or a power supply line as a transmission medium, and specifically includes the following steps:

the method comprises the steps that first equipment sends an acquisition request of specified file data;

the second device reads the file data and converts the file data into binary data;

modulating the binary data into a low operation amount and a high operation amount of a CPU (Central processing Unit), so that a current signal of equipment regularly fluctuates, and transmitting the current signal through the power transmission line or the power supply line;

the first device detects the current signal, acquires the current signal, demodulates the current signal into a digital signal and converts the digital signal into file data.

Preferably, the modulation is binary frequency shift keying modulation.

Preferably, the modulating the binary data into the low operand and the high operand of the CPU specifically includes determining whether the binary data is "0" or "1", and if "0", executing the CPU operation with the time length T, and if "1", executing the CPU operation with the time length 2T.

Preferably, after the CPU operation is executed, it is determined whether the file is completely transmitted, and if not, the step of continuously reading the file data is returned to.

Preferably, the power of the CPU is in the range of 20-150W, wherein the power of the CPU is 20W at low computation and 150W at high computation.

According to another embodiment of the present invention, the present invention further provides a data ferry system based on a network isolation condition, the system implementing data ferry between different devices using a power transmission line or a power supply line as a transmission medium, the system including:

a sending means for sending an acquisition request specifying file data;

reading means for reading the file data and converting the file data into binary data;

processing means for modulating said binary data into a low operand and a high operand of a CPU so that a current signal of the device regularly fluctuates and transmitting said current signal through said power transmission line or power supply line;

and the capturing device is used for detecting the current signal, acquiring the current signal, demodulating the current signal into a digital signal and converting the digital signal into file data.

Preferably, the processing device further includes a CPU operation module, configured to determine whether the binary data is "0" or "1", if "0", execute the CPU operation with the time length T, and if "1", execute the CPU operation with the time length 2T.

Preferably, the CPU operation module is further configured to determine whether the file is sent completely after the CPU operation is performed, and if not, continue to return to the step of reading the file data.

The invention provides a data transmission scheme for transmitting signals by using current disturbance of a power supply line of computer equipment, and has the following technical effects:

(1) the limitation of network isolation is effectively broken through, and data communication is realized;

(2) the problem that the conventional means is easy to monitor and find is avoided;

(3) longer transmission distances can be achieved at less expense.

Drawings

Fig. 1 is a diagram of a data ferrying method architecture based on network isolation according to the present invention;

FIG. 2 is a flow chart of a data ferry method based on network isolation according to the present invention;

fig. 3 is a flowchart of a data transmission method based on network isolation according to the present invention;

FIG. 4 is a CPU operation workflow diagram based on network isolation conditions according to the present invention;

FIG. 5 is a diagram of the CPU operation load under the network isolation condition according to the present invention;

FIG. 6 is a schematic diagram of a capture device based on network isolation according to the present invention;

FIG. 7 is a diagram of a capture device in a network isolation condition according to the present invention;

FIG. 8 is a graph of a power line current signal and demodulated data in accordance with an embodiment of the present invention;

fig. 9 is a frame diagram of a data ferry system based on network isolation according to the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

The realization of the data transmission technology under the network isolation condition provided by the invention needs a mode of combining special software in a computer and external signal acquisition equipment. As shown in fig. 1, a computer device acquires document data from a target device, the transmission medium of which is a power line or a power supply line, and restores the document data after collection based on a current signal.

As shown in fig. 2, when data transmission is required between two pieces of computer equipment, the computer equipment receives an acquisition request for data of a designated file, at this time, dedicated software in the computer equipment starts to run, and reads the designated file after finding the designated file according to the position of the designated file. At this time, the read file is converted into binary data. The software realizes the conversion of files into binary data in a JAVA programming mode.

In the binary data, only "0" and "1" are included, so that the efficiency of data modulation is improved, the present embodiment uses binary frequency shift keying modulation to implement data modulation, in which data is represented by a change in carrier frequency, and this modulation also uses only two different carrier frequencies, each of which is amplitude modulation, so that "0" and "1" are used as symbol combinations that meet the requirement.

In this embodiment, as shown in fig. 3. In the process of completing the modulation of the data, the method further comprises modulating the binary data into a low operation component and a high operation component of the CPU, and the special software in the embodiment enables the power of the device to be regularly changed by calling the CPU to realize the low operation amount and the high operation amount, so that the current in the power supply line fluctuates along with the fluctuation, which is specifically referred to below. Thus, the present embodiment defines the operating times T and 2T of the CPU, corresponding to binary data "0" and "1", respectively. And judging whether the received file is converted into binary data, wherein the binary data is '0' or '1', if the binary data is '0', executing the CPU operation with the time length of T, and if the binary data is '1', executing the CPU operation with the time length of 2T. Fig. 4 shows the workflow diagram of the CPU at T and 2T run times. And after the operation is executed, judging whether the file is sent or not, and if not, returning to the step of reading the file.

The key code for the data modulation implementation is as follows:

file = OpenFile (FileName);// open specified File

DataBuf = ReadFile (File)// reading the file into the buffer

While（DataBuf != End）

{

BinBuf = GetBinData（DataBuf）;

If（BinBuf == ‘0’）

{

FullRunCPU (T), making CPU run at full speed for time T

}

else

{

FullRunCPU (2T), making the CPU run at full speed for 2T

}

}。

The power range of a CPU (central processing unit) in a common computer device is typically 20-150W (watts), with 20W for low computation and 150W for high computation. The power fluctuation of the computer can be realized by different operation densities of software. From the knowledge of the electric power, the power P (watt) consumed by the electric equipment is the product of the voltage U (volt) and the current I (ampere), and the formula is as follows: p ═ U × I.

The fluctuation range of the power supply voltage U is small and can be regarded as constant basically, so that P and I are in a positive correlation relationship. I can be changed as soon as P is changed, detecting I can infer P, so data can be transferred to the outside by making regular changes in the device power P.

The two are known to be in a positive correlation: p ⇋ I, therefore, the software regularly realizes high computation and low computation in the computer, which can cause the current to regularly fluctuate, and then the current is monitored by the current signal acquisition point on the power supply line and is restored into a digital signal. As shown in fig. 5, a diagram of the CPU operational load.

In the embodiment of the invention, a current signal capturing device is adopted for collecting the current signal, and the principle of the current signal capturing device is shown in fig. 6, and the physical diagram is shown in fig. 7.

Finally, the acquired current signal is demodulated by a capturing device, and finally file data is obtained, as shown in fig. 8.

According to another embodiment of the present invention, the present invention further provides a data ferry system based on a network isolation condition, as shown in fig. 9, where the system uses a power transmission line or a power supply line as a transmission medium, the system includes: the device A and the device B can carry out data communication under the network isolation condition.

The apparatus A (apparatus B) includes:

a sending means for sending an acquisition request specifying file data;

and the capturing device is used for detecting the current signal generated by other equipment (such as the equipment B), acquiring the current signal, demodulating the current signal into a digital signal and converting the digital signal into file data. As shown in fig. 6 and 7.

The processing device also comprises a CPU operation module which is used for judging whether the binary data is '0' or '1', if the binary data is '0', executing the CPU operation with the time length of T, and if the binary data is '1', executing the CPU operation with the time length of 2T.

The CPU operation module is also used for judging whether the file is sent completely or not after the CPU operation is finished, and if not, returning to the step of reading the file.

In summary, the present invention provides a data ferrying method and system based on network isolation, wherein a power line or a power supply line is used as a transmission medium, the data transmission technical scheme is used under the network isolation condition that a signal is transmitted by using current disturbance of an ac power supply line of a computer device, the computer isolated by the network can still transmit data to the outside, a power line current signal capture device is implemented, the device can capture the magnitude of a current signal of the power line, and the technical scheme of data modulation and demodulation is used for modulating data into the current of the computer power supply line and can be captured and demodulated. Thereby finally realizing the transmission process of the file. The limitation of network isolation is effectively broken through, and ferry communication of data is realized; the problem that the conventional ferry communication means is easy to monitor and find is solved; thereby enabling a longer transmission distance to be achieved at a lower cost.

It will be evident to those skilled in the art that the embodiments of the present invention are not limited to the details of the foregoing illustrative embodiments, and that the embodiments of the present invention are capable of being embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the embodiments being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned. Furthermore, it is obvious that the word "comprising" does not exclude other elements or steps, and the singular does not exclude the plural. Several units, modules or means recited in the system, apparatus or terminal claims may also be implemented by one and the same unit, module or means in software or hardware. The terms first, second, etc. are used to denote names, but not any particular order.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention and not for limiting, and although the embodiments of the present invention are described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the embodiments of the present invention without departing from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A data ferrying method based on a network isolation condition, wherein a power transmission line or a power supply line is used as a transmission medium, and the method is characterized by comprising the following steps of:

the binary data are used for modulating the low operation amount and the high operation amount of the CPU, so that the current signal of the equipment regularly fluctuates and is transmitted through the power transmission line or the power supply line, and the method specifically comprises the following steps:

judging whether the binary data is '0' or '1', if the binary data is '0', executing a CPU high operand with the time length of T to enable the current signal to maintain the high current with the time length of T, if the binary data is '1', executing a CPU high operand with the time length of 2T to enable the current signal to maintain the high current with the time length of 2T, and if the CPU does not execute the high operand, executing a low operand to enable the current signal to be in a low current signal state;

the power range of the CPU is 20-150W, wherein the power of the CPU is 20W when the computation amount is low, and the power of the CPU is 150W when the computation amount is high.

2. The data ferry method based on the network isolation condition as claimed in claim 1, wherein after the CPU operation is executed, it is determined whether the file is sent completely, and if not, the step of continuing to read the file data is returned.

3. A data ferry system based on network isolation conditions, wherein the system realizes data ferry between different devices by taking a power transmission line or a power supply line as a transmission medium, and the system comprises:

a sending means for sending an acquisition request specifying file data;

processing means for modulating said binary data into a low operand and a high operand of a CPU so that a current signal of the device regularly fluctuates and transmitting said current signal through said power transmission line or power supply line; the modulation is binary frequency shift keying modulation;

the capturing device detects a current signal in the power transmission line or the power supply line in an electromagnetic coupling mode, acquires the current signal, demodulates the current signal into a digital signal and converts the digital signal into file data;

the processing device also comprises a CPU operation module, which is used for judging whether the binary data is '0' or '1', if the binary data is '0', executing a CPU high operation amount with the duration of T so that the current signal maintains the high current with the duration of T, if the binary data is '1', executing the CPU high operation amount with the duration of 2T so that the current signal maintains the high current with the duration of 2T, and if the CPU does not execute the high operation amount, executing a low operation amount so that the current signal is in a low current signal state;

4. The data ferry system based on the network isolation condition as claimed in claim 3, wherein the CPU operation module is further configured to determine whether the file is sent completely after the CPU operation is performed, and if not, return to the step of continuously performing reading of the file data.