JPH11298740A - Data transmission/reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent restored images from being obtained by an wiretappes, even if was able to wiretap the transmission data from a communication channel during facsimile transmission. SOLUTION: A transmission side equipment codes an original image 21 by a modified modified Huffman (MMR) coding method and obtains compressed image data 22. Dummy added data 23, for which the dummy data of optional contents are added to the head part of the compressed image data by an arbitrary byte number and non-standardized function setting signals (NSS) for setting the byte number of the dummy data are sent out together. A reception side equipment receives the non-standardized function setting signals (NSS) and the dummy added data, removes the byte number of the added dummy data from the lead part of the dummy added data 23, and then restores the image data and prints them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission / reception method using a facsimile machine or the like.

[0002]

2. Description of the Related Art In recent years, with the spread of office automation, the use of information processing using communication lines has been promoted as a part of streamlining office work in offices. Among them, the use of facsimile machines has expanded especially, the manufacturing industry,
Trading companies have expanded into the financial industry and even the general household. Already, facsimile machines have become the most convenient means for sending documents and slips. Along with this, it is becoming an important issue to protect the confidentiality of the contents written on documents and slips.

[0003]

However, the above-mentioned conventional techniques have the following problems to be solved. In a normal image transmission / reception method, it is relatively easy to eavesdrop and record the transmission data from a communication line during facsimile transmission and decode this data to obtain a restored image. On the other hand, there are tools and the like for encrypting transmission data. However, these tools require hardware separately from the facsimile apparatus, which leads to high cost and has not been widely used.

[0004]

The present invention adopts the following constitution in order to solve the above points. <Structure 1> In transmitting and receiving digital data, the digital data is encrypted and transmitted by adding dummy data of arbitrary contents to the head of the digital data, and the transmitting side transmits the digital data to the receiving side. Then, the length information of the dummy data is notified by another communication, and the receiving side deletes the dummy data from the received data based on the length information and restores the encrypted digital data. Characteristic data transmission / reception method.

<Configuration 2> In the data transmission / reception method described in Configuration 1, the transmission-side facsimile apparatus compresses the image data line by line, and further performs compression using the comparison result between the previous line and the rear line. By creating continuous digital data and adding dummy data at the beginning,
A data transmission / reception method, wherein the digital data is encrypted, and the length information of the dummy data is included in a non-standard function setting signal transmitted from a transmission side to a reception side during execution of facsimile communication means.

<Structure 3> In transmitting and receiving digital data, the digital data is encrypted and transmitted by adding dummy data of an arbitrary content to the head of the digital data, and the transmitting side is transmitted to the receiving side. On the other hand, the generation information of the dummy data is notified by another communication, and the receiving side generates dummy data based on the generation information of the dummy data, and deletes the dummy data from the reception data. A data transmission / reception method for restoring encrypted digital data.

<Structure 4> In the data transmission / reception method described in Structure 3, the facsimile apparatus on the transmission side compresses the image data line by line, and further performs compression using the comparison result between the previous line and the rear line. In the non-standard function setting signal transmitted from the transmission side to the reception side while the facsimile communication means is being executed, the dummy data is encrypted by adding dummy data to the beginning of the digital data and adding the dummy data to the beginning of the digital data. A data transmission / reception method characterized by including generation information of the data.

<Structure 5> In transmitting and receiving digital data, the digital data is encrypted by adding dummy data of arbitrary contents to the head of the digital data, and then the dummy data portion is deleted. While transmitting, the transmitting side notifies the receiving side of the generation information of the dummy data by another communication, and the receiving side generates and encrypts the dummy data based on the generation information of the dummy data. A method of transmitting and receiving data, comprising: adding the encrypted dummy data to the received data, restoring the encrypted digital data, and deleting the dummy data.

<Structure 6> In the data transmission / reception method according to Structure 4 or 5, a plurality of types of dummy data are stored in advance in the facsimile apparatus on the receiving side, and the generation information of the dummy data is A data transmission / reception method comprising selection information for selecting any one of the dummy data.

<Structure 7> In the data transmission / reception method described in Structure 6, the dummy data generation information is the same as the dummy data added on the transmitting side by a predetermined arithmetic processing in the receiving-side facsimile apparatus. A data transmission / reception method comprising an arithmetic expression.

<Structure 8> In the data transmission / reception method described in Structure 7, the selection information comprises an arithmetic expression using common information that can be independently acquired by the transmission side and the reception side as a parameter. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. <Structure of Embodiment 1> FIG. 1 is an explanatory diagram of a data coding method according to Embodiment 1. Before describing FIG. 1, an overview of the entire facsimile apparatus will be described with reference to the drawings. FIG. 2 is a block diagram of the facsimile apparatus according to the first embodiment. As shown in FIG. 2, the facsimile apparatus on the transmission side includes an operation display unit 1 and a read coding unit 2
, Print decoding unit 3, memory unit 4, procedure processing unit 5
, A line controller 6 and a controller 7.

The operation display section 1 has a panel display, and is a section where an operator gives an operation instruction while watching the display. The read coding unit 2 is a unit that reads image information on a document by a scanner and compresses data from the read image data to obtain compressed image data conforming to the facsimile communication format. The print decoding unit 3 is a part that decodes the compressed image data received via the communication line 20 and restores the image data to print.

The memory section 4 is a section for storing the compressed image data and the like. The procedure processing unit 5 is a part that processes and proceeds with a communication procedure performed between the transmitting side and the receiving side via the communication line 20 at the time of facsimile communication. The line control unit 6 is an interface unit that controls outgoing and incoming calls between the facsimile machine and the communication line 20. The control unit 7 is a part that controls the entire facsimile machine, and includes a CPU (Central Processing Unit) and the like.

In the present invention, the facsimile apparatus on the transmitting side having the above-described configuration and the facsimile apparatus on the receiving side described below are arranged and communicated with each other via the communication line 20 and the exchange 10. The configuration of the facsimile apparatus on the receiving side is the same as the configuration of the facsimile apparatus on the transmitting side, but for convenience of explanation, the reference numerals of the respective components are separately defined as follows. The facsimile apparatus on the receiving side includes an operation display unit 11, a read coding unit 12, a print decoding unit 13, a memory unit 14, a procedure processing unit 15, a line control unit 16, and a control unit 17.

<Operation of Embodiment 1> In the present invention, the communication protocol is MMR (Modified Modified Huffuman).
Apply coding methods. The MMR coding method is defined in ITU (International Telecommunication Union) -T Recommendation T-6. The features of this method are as follows.

1. Information on the sweep line to be processed,
Only the change from the information one sweep cycle before is coded. 2. When processing the first sweep line on the manuscript,
As the information before the sweep cycle, a white line is assumed virtually. As a result, if data loss, addition, or the like occurs in the middle of a page, the receiving side that has received the compressed image data has a characteristic that the subsequent image data cannot be restored.

Returning to FIG. 1, a data coding method according to the first embodiment, to which the above-described MMR coding method is applied, will be described. In FIG. 1, (a) shows the original image 21, (b) shows the compressed image data 22 after coding, and (c) shows the dummy additional data 23. The virtual white line shown at the top of FIG.
This is a virtual white line assumed as information before one sweep cycle described in the feature 2 of the R coding method. (B)
(A) shows the state of compressed image data after coding in order from the top.

Here, the length of the line differs from line to line and is not constant. This means that the compressed image data has a different information amount from line to line. (C)
Represents dummy additional data in which dummy line data of an arbitrary number of bytes is added to the head of (a).

Here, it should be noted that, even if the eavesdropping by the eavesdropper shown in (c), the dummy additional data is correct unless the number of bytes of the added dummy line data is accurately removed. It cannot be restored. It is also conceivable that the line length information is included in the header when each line is separated in the receiving facsimile machine. In this case, however, the code is known only to the transmitting facsimile device and the transmitting facsimile device. , The start position of the compressed image data can be prevented from being decoded.

Hereinafter, the operation of the first embodiment will be described with reference to FIG. In the facsimile machine on the transmitting side, the control unit 7
The following operation is advanced based on the control of. The reading coding unit 2 reads image information on a document with a scanner. The read image data is compressed into compressed image data by the MMR coding method.

The compressed image data is stored in the memory unit 4. Further, dummy line data of an arbitrary number of bytes is additionally stored at the head of the compressed image data. As the dummy line data, data input by the operator from the operation display unit 1 and stored in the memory unit 4 in advance is used. Alternatively, it may be generated each time using a special function.
However, the content of the dummy line data may be arbitrary.

Next, a description will be given of a transmission control procedure for transmitting dummy additional data, in which dummy line data of an arbitrary number of bytes is added to the head of the compressed image data, from the transmitting facsimile apparatus to the receiving facsimile apparatus. . FIG. 3 is an explanatory diagram of a transmission control procedure according to the first specific example. In the figure, the operating subject on the left is a transmitting facsimile machine, and the operating subject on the right is a receiving facsimile machine. An exchange (10 in FIG. 2) is interposed between them. The operation procedure proceeds from the top to the bottom of the figure. Operation procedure S1 in the figure
Steps S6 to S6 will be described in order.

S1. The line controller 6 (FIG. 2) of the transmitting facsimile machine calls (Diailing) the fax number of the receiving facsimile machine via the exchange. S2. The receiving-side facsimile apparatus receives the calling signal (Calling) via the exchange, and
Through (FIG. 2), the called terminal identification signal (CED) is transmitted toward the transmitting facsimile machine. Furthermore, digital identification signal (DIS), non-standard function identification signal (NSF)
To the transmitting facsimile machine. This procedure is to notify the transmitting facsimile apparatus that the receiving facsimile apparatus has the encryption capability.

S3. In step S2, the transmission-side facsimile apparatus that has accepted the signal transmitted by the transmission-side facsimile apparatus recognizes that the reception-side facsimile apparatus has encryption capability by the processing of the procedure processing unit 5 (FIG. 2). I do. S4. The transmitting-side facsimile apparatus transmits a non-standard function setting signal (NSS) and a training check signal (TCF) to the receiving-side facsimile apparatus through the line controller 6 (FIG. 2).

In this procedure, the encrypted communication is specified, and the number of bytes of dummy additional data (defined as length information) obtained by adding an arbitrary number of bytes to the head of the compressed image data is defined by the line control unit 6 (FIG. This is a procedure for notifying the receiving facsimile apparatus through 2). The length information of the dummy additional data is set in the non-standard function setting signal (NSS). Since the non-standard function setting signal (NSS) is a maker's own code, its configuration and procedure are not disclosed to the public. Therefore, it has confidentiality. Further, a training check signal (TCF) is transmitted and preparation for transmission is started.

S5. In step S4, the receiving-side facsimile apparatus that has received the non-standard function setting signal (NSS) transmitted by the transmitting-side facsimile apparatus performs processing of the procedure processing unit 15 (FIG. 2) to specify encrypted communication and dummy additional data. Know the number of bytes in Further, after receiving the training check signal (TCF), the reception preparation confirmation signal (CF
R) is sent to complete the preparation for receiving the dummy additional data.

S6. The transmission-side facsimile apparatus that has received the reception preparation confirmation signal (CFR) recognizes that the reception-side facsimile apparatus has completed preparation for receiving dummy additional data. Thereafter, the dummy additional data stored in the memory unit 4 (FIG. 2) is read out, and transmission to the receiving facsimile apparatus is started through the line control unit 6 (FIG. 2). The transmission control procedure between the transmitting facsimile apparatus and the receiving facsimile apparatus has been described above, and the operation inside the receiving facsimile apparatus will be described.

After receiving the dummy additional data, the receiving facsimile apparatus temporarily stores the data in the memory unit 14. Here, the dummy line data is removed from the head of the compressed image data by the number of bytes specified in S5. The print decoding unit 13 restores the compressed image data from which the dummy line data has been removed into image data and prints the image data.

<Effect of Specific Example 1> As described above,
According to the image transmission / reception method of the facsimile apparatus according to this specific example, even if an eavesdropper can eavesdrop on the transmission data from the communication line during facsimile transmission, it is not possible to obtain a restored image. That is, since the non-standard function setting signal (NSS) in which the number of bytes of the added dummy line data is set is a maker's own code, its configuration and procedure are not disclosed to the public. Therefore, since the number of bytes of the added dummy line data cannot be known accurately, it cannot be accurately removed, and the image data cannot be restored correctly. Further, since this method does not require any special hardware, it is possible to protect the confidentiality of the content transmitted by facsimile without increasing the cost.

<Structure of the specific example 2>
Confidentiality is further improved. FIG. 4 is a block diagram of a facsimile apparatus according to the second embodiment. As shown in FIG.
, Read coding unit 2 and print decoding unit 3
, A memory unit 8, a procedure processing unit 5, a line control unit 6,
The control unit 7 is provided. Only differences from the first example will be described. The memory section 4 is a section for storing the compressed image data and the like. Furthermore, a dummy line table 9 is provided inside.
This is also a part for storing dummy line data.

Next, an example of a dummy line data configuration will be described. FIG. 5 is an explanatory diagram of dummy line data according to the second embodiment. 00 at the beginning of the dummy line data
Dummy line IDs 1 to K are assigned. Further, the same contents of the dummy line data are registered in advance in both the transmitting facsimile machine and the transmitting facsimile machine. Other parts are the same as in the first embodiment.

FIG. 6 is an explanatory diagram of a data coding method according to the second embodiment. As in the specific example 1, in FIG. 6 which describes a data coding method to which the above MMR coding method is applied,
(A) shows an original image, (b) shows an image to which a dummy line is added, (c) shows compressed image data after coding, and (d) shows data after a dummy line is deleted.

The virtual white line shown at the top of (a) is a virtual white line assumed as information one sweep cycle before described in the feature 2 of the MMR coding method.
(B) is a diagram in which a dummy line is added between the virtual white line and the first line of actual data in (a). (C)
(B) shows the state of the compressed image data after coding in order from the top. Here, the length of the line differs from line to line and is not constant.
This means that the amount of information differs for each line.
(D) represents dummy deleted data in which dummy line data has been deleted from the beginning of (c).

Here, it should be noted that, as shown in (d), even if the eavesdropping on the dummy deletion data is performed, the dummy deletion data cannot be correctly restored unless the deleted dummy line data is accurately added. That is. Hereinafter, FIG.
The operation of the specific example 2 will be described with reference to FIG.

In the facsimile machine on the transmitting side, the control unit 7
The following operation is advanced based on the control of. The reading coding unit 2 reads image information on a document with a scanner. Next, the dummy line data of the specific dummy line ID number stored in the dummy line table 9 is read. This dummy line data is added to the head of the already read image data together with the virtual white line. Thereafter, it is compressed into compressed image data by the MMR coding method.

The compressed image data is temporarily stored in the memory unit 8. Next, a portion of the dummy line data is deleted from the compressed image data to form dummy deletion data. This dummy deletion data is stored in the memory unit 8 again. Next, a transmission control procedure for transmitting the dummy deletion data from the transmitting facsimile apparatus to the receiving facsimile apparatus will be described. FIG. 7 is an explanatory diagram of a transmission control procedure according to the second specific example. In the figure, the operating subject on the left is a transmitting facsimile machine, and the operating subject on the right is a receiving facsimile machine. An exchange (10 in FIG. 2) is interposed between them.

Only the differences from the first embodiment (FIG. 3) will be described. From step S1 to step S3, the transmitting facsimile apparatus recognizes that the receiving facsimile apparatus has encryption capability by following exactly the same procedure as in the specific example 1 (FIG. 3) S4. The transmission-side facsimile apparatus includes a line control unit 6
The transmission terminal identification signal (TCF) and the non-standard function setting signal (NSS) are transmitted to the reception-side facsimile apparatus through (FIG. 4). In this procedure, the encrypted communication is specified, and the dummy line ID number of the dummy line data deleted from the head of the compressed image data is set in the non-standard function setting signal (NSS) to notify the receiving facsimile apparatus. .

At the same time, the training check signal (TC
F) is sent to start preparation for transmission. After this, S5 and S6,
By following exactly the same procedure as in the specific example 1 (FIG. 3), the transmitting-side facsimile apparatus recognizes that the receiving-side facsimile apparatus has completed preparation for receiving dummy deletion data.
Thereafter, the dummy deletion data stored in the memory unit 8 (FIG. 4) is read out, and transmission to the reception-side facsimile apparatus is started through the line control unit 6 (FIG. 4). The transmission control procedure between the transmitting facsimile apparatus and the receiving facsimile apparatus has been described above, and the operation inside the receiving facsimile apparatus will be described.

After receiving the dummy deletion data, the receiving facsimile apparatus temporarily stores the data in the memory unit 18 (FIG. 4). Here, the dummy line data of the dummy line ID number specified in S4 is read from the dummy line table. After adding a white line to the head of the dummy line data, the read coding unit 12
Compress by coding method. Next, the compressed dummy line data is added to the head of the compressed image data received from the transmitting facsimile machine. Thereafter, the print decoding unit 13 restores this data, discards the dummy data added at the head, and prints.

In the above description, the method of selecting the dummy line ID number is not specified. However, the dummy line ID number can be selected by the following method. 1. The operator arbitrarily selects an ID number and operates the operation display unit 1
How to operate and input. This method includes a case where the same ID number is selected for all pages of the transmission original and a case where the ID number is set for each page.
The number may change.

2. The operator arbitrarily selects an ID number,
When the user operates and displays the operation display unit 1, the first page is
Although the ID number is selected by the operator, the ID number may change according to a specific rule from the next page. For example, when modulo conversion is performed by adding a constant number to a geometric series.

3. The case where the operator is automatically selected based on a predetermined specific reference number without selecting an ID number. For example, when a specific date and time is set as a reference number and automatically selected according to a specific rule. In this case, the synchronization of the date and time in the transmission-side facsimile apparatus and the reception-side facsimile apparatus includes, for example, a clock unit 30 (FIG. 4) and a clock unit 40 (FIG. 4) for measuring the date and time, respectively. This is easily done by providing.

The rule for generating the dummy data described above is defined as an arithmetic expression. Further, information necessary for reading the dummy data stored in the memory on the receiving side in advance, for example, information serving as a reference number of the arithmetic expression and the ID number are defined as dummy data generation information.

In the above description, the present invention is limited to the facsimile apparatus. However, the present invention is not limited to the facsimile apparatus. The present invention can be applied to any image transmitting and receiving apparatus having the above. For example, the present invention can be applied to an image transmitting / receiving apparatus using a personal computer.

<Effect of Specific Example 2> As described above,
According to the image transmission / reception method of the facsimile apparatus according to this specific example, even if an eavesdropper can eavesdrop on the transmission data from the communication line during facsimile transmission, the dummy line corresponding to the dummy line ID number is previously determined. You cannot get a restored image unless you have the data.
Therefore, the confidentiality of the content transmitted by facsimile can be more protected than the image transmission / reception method of the facsimile apparatus according to the first embodiment.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a data coding method according to a specific example 1.

FIG. 2 is a block diagram of a facsimile apparatus according to a specific example 1.

FIG. 3 is an explanatory diagram of a transmission control procedure according to a specific example 1.

FIG. 4 is a block diagram of a facsimile apparatus according to a second embodiment.

FIG. 5 is an explanatory diagram of dummy line data according to a specific example 2.

FIG. 6 is an explanatory diagram of a data coding method according to a specific example 2.

FIG. 7 is an explanatory diagram of a transmission control procedure according to a specific example 2.

[Explanation of symbols]

 21 Original image 22 Compressed image data after coding 23 Dummy additional data

Claims (8)

[Claims] When transmitting and receiving digital data, the digital data is encrypted and transmitted by adding dummy data having an arbitrary content to the head of the digital data, and the transmitting side transmits the digital data to the receiving side. Then, the length information of the dummy data is notified by another communication, and the receiving side deletes the dummy data from the received data based on the length information and restores the encrypted digital data. A data transmission / reception method characterized by the above-mentioned. 2. The data transmission / reception method according to claim 1, wherein the transmission-side facsimile apparatus compresses the image data line by line, and further compresses the image data using a comparison result between the previous line and the rear line to continuously perform the compression. By adding dummy data to the beginning of the digital data and encrypting the digital data, the non-standard function setting signal transmitted from the transmitting side to the receiving side during execution of the facsimile communication means includes:
A data transmission / reception method comprising length information of the dummy data. 3. When transmitting and receiving digital data, the digital data is encrypted and transmitted by adding dummy data of an arbitrary content to the head of the digital data, and transmitted from the transmitting side to the receiving side. Then, the generation information of the dummy data is notified by another communication, and the receiving side generates the dummy data based on the generation information of the dummy data, deletes the dummy data from the reception data, and performs encryption. Data transmission / reception method for restoring digital data obtained. 4. The data transmission / reception method according to claim 3, wherein the facsimile apparatus on the transmission side compresses the image data line by line and further performs compression using a comparison result between the previous line and the rear line. The non-standard function setting signal transmitted from the transmission side to the reception side during execution of facsimile communication means is encrypted by adding dummy data to the beginning of the digital data as dummy data and adding the dummy data to the head of the digital data. A data transmission / reception method including generation information. 5. When transmitting and receiving digital data, the digital data is encrypted by adding dummy data of an arbitrary content to the head of the digital data, and then the dummy data portion is deleted and transmitted. At the same time, the transmission side notifies the reception side of the generation information of the dummy data by another communication, and the reception side generates and encrypts the dummy data based on the generation information of the dummy data. And a method of adding the encrypted dummy data to the received data, restoring the encrypted digital data, and then deleting the dummy data. 6. The data transmitting / receiving method according to claim 4, wherein a plurality of types of dummy data are stored in advance in the facsimile apparatus on the receiving side, and the generation information of the dummy data is stored in the plurality of types of dummy data. A data transmission / reception method comprising selection information for selecting any one of the dummy data. 7. The data transmission / reception method according to claim 6, wherein the dummy data generation information generates the same dummy data as the dummy data added on the transmission side by a predetermined arithmetic processing in the reception-side facsimile apparatus. A data transmission / reception method characterized by comprising an arithmetic expression. 8. The data transmission / reception method according to claim 7, wherein the selection information comprises an arithmetic expression using, as a parameter, common information that can be independently acquired by the transmission side and the reception side.