JP2002300410A - Facsimile communication method and facsimile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the Internet facsimile communication which utilizes a conventional IN-NIKS decoding system in which a common key being not generated. SOLUTION: Prior to transmission/reception of facsimile image data to be transmitted/received as an e-mail, a transmission side facsimile FS and a receiving side facsimile FR inform individually stored characteristic information to each other and generate decoding keys, respectively, based on that information and characteristic information (ID) held in both facsimiles FS and FR. Facsimile image data, decoded by this decoding key, are then transmitted from the transmission side facsimile FS as a file affixed to an e-mail, and the decoded facsimile image data in the affixed file of an e-mail received by the receiving side facsimile FR decoded, using the decoding key.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile communication method and a facsimile apparatus, and more particularly to a facsimile communication method and a facsimile apparatus for transmitting / receiving facsimile image data as electronic mail via a computer network such as the Internet. The present invention relates to a facsimile communication method and a facsimile apparatus for encrypting data and communicating the same as electronic mail.

[0002]

2. Description of the Related Art In recent years, a so-called Internet facsimile apparatus has been developed which can be connected to a computer network such as the Internet, and which can transmit and receive data to be transmitted as facsimile image data as electronic mail. ing.

[0003] On the other hand, in an e-mail using a computer network such as the Internet, there is a relatively high possibility that a communication content is stolen from a computer network by a third party. In normal facsimile communication, encrypted communication has been used to transmit and receive important documents, but it is necessary to share an encryption key between transmitting and receiving devices in advance for normal encrypted communication. Yes, that required advance preparation.
However, for example, ID-NIKS (ID-based Non-Interactive Key
In an encryption system called “Sharing Scheme”, information is encrypted / decrypted with an encryption key created based on the unique information of both communicating parties, so there is no need to share an encryption key in advance, and therefore, there is no Since no preparation is required, encrypted communication can be used easily.

[0004] The ID-NIKS is a method of sharing an encryption key using the ID of a communication partner as unique information without performing preliminary communication, and there is no need to exchange a public key and a secret key between a transmitter and a receiver. Also, this method does not require a key list and a service by a third party, and secure communication can be performed between arbitrary entities.

[0005] Specifically, ID-NIKS stores ID (Identity) information for specifying an individual such as an address, a name, a name, a telephone number, and a mail address of each entity (entity; person, computer, facsimile machine, etc.). This is an encryption system used to generate an encryption key. In this ID-NIKS,
A common encryption key (common key) between sender and receiver based on ID information
Is generated, so that the preliminary communication is not required as described above, so that the convenience is high. Therefore, in Internet facsimile communication using a computer network as described above, it is conceivable to perform encrypted communication using this ID-NIKS with a mail address as ID information for both.

The principle of ID-NIKS will be described below. Assuming the existence of a reliable center, a common key generation system is configured around this center. The ID information such as the name, address, telephone number, and mail address of the entity X is represented by h (ID _X ) using a hash function h (·). The center sends secret information S _Xi to an arbitrary entity X based on center public information {PC _i }, center secret information {SC _i }, and ID information h (ID _X ) of the entity X as follows. Calculate and secretly distribute to Entity X. S _Xi = F _i ({SC _i }, {PC _i }, h (ID _X ))

Entity X is any other entity
A common key K for encryption and decryption with Y_XYTo
Titty X's own secret information $ S_Xi｝, Center public information
｛PC _iID and the ID information h (I
D_Y) Is generated as follows. K_XY= F (｛S_Xi｛, ｛PC_i｝, H (ID_Y))

[0008] Similarly, the entity Y generates a key to the entity X as a common key _KYX . If always K _XY
If the relationship of = K _YX is established, the keys K _XY and K _YX can be used as the encryption key and the decryption key between the entities X and Y.

A general public key cryptosystem, for example, R
In the case of the SA encryption system, the length of the public key is ten and several times the current telephone number, which is extremely complicated. In contrast, in ID-NIKS, by registering each ID information in the form of a list in advance, it is possible to generate a common key by referring to this list without any preliminary communication with any entity. it can.

Therefore, when communication is performed between two facsimile apparatuses, the two facsimile apparatuses need to have a center public information {PC _i } and a center secret information {S
ID information h which is C _{i あ}る and each mail address
Based on (ID _X ), secret information S _Xi is calculated, distributed secretly, and stored. Then, the two facsimile apparatuses transmit a common key K _XY for encryption and decryption to their own secret information {S _Xi }, center public information {PC _i }, and the other party when communicating with each other. Is generated as follows using the ID information h (ID _Y ) of K _XY = f ({S _Xi }, {PC _i }, h (ID _Y ))

[0011]

As described above, by using each mail address as an ID,
Encrypted communication using ID-NIKS can be easily performed between Internet facsimile machines using a computer network such as the Internet. By the way, when such an encrypted communication using ID-NIKS is performed by an Internet facsimile apparatus, the ID-NIKS encryption function must be used between the transmitting apparatus and the receiving apparatus, and both functions required for that purpose are used. Must be known in advance.

For this reason, it is most practical to use both mail addresses as IDs. For example, in an Internet facsimile apparatus such as an MTA (Mail Transfer Agent) type having a mail server function, the domain names should match. Since different e-mail addresses can be accepted, it is necessary to correspond to a plurality of e-mail addresses. Therefore, the MTA-type Internet facsimile apparatus needs to hold all the e-mail addresses that it can accept and the IDs (e-mail addresses) of a plurality of senders to them, which is not practical. Even if all the IDs (e-mail addresses) are held, it is possible to generate a common key in a number obtained by combining the IDs, so that the received encrypted data can be decrypted by all of the plurality of common keys. The process of trying to make it necessary is required. For this reason, there is a possibility that the MTA-type Internet facsimile machine cannot decrypt the Internet facsimile communication using the ID-NIKS encryption function when receiving it.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and a facsimile communication method of an Internet facsimile system capable of always generating a common key reliably and therefore always performing encrypted communication. It is intended to provide a facsimile machine.

[0014]

In order to achieve the above-mentioned object, in the facsimile communication method and facsimile apparatus of the present invention, IDs are exchanged in advance by e-mail prior to transmission / reception of facsimile image data to be transmitted / received. Later, facsimile image data is transmitted and received by the ID-NIKS encryption function.

In a facsimile communication method according to the present invention, facsimile image data encrypted with an encryption key based on unique information of both a transmitting side device and a receiving side device is transmitted from the transmitting side device as an electronic mail. A facsimile communication method for decrypting with the encryption key, wherein the two devices mutually notify unique information stored individually by e-mail prior to transmission / reception of image data.

In the facsimile communication method according to the present invention, both the transmitting device and the receiving device store their unique information. By exchanging information by e-mail in advance, an encryption key is generated based on both pieces of unique information. Thereafter, the facsimile image data encrypted with the encryption key generated in this manner is transmitted from the transmitting device, and received by the receiving device. The receiving-side apparatus decrypts the received encrypted facsimile image data using the previously generated encryption key.

A first invention of a facsimile apparatus according to the present invention is a facsimile apparatus for transmitting facsimile image data encrypted with an encryption key based on each unique information of itself and a communication partner to the communication partner as an electronic mail. The facsimile image data to be transmitted with the encryption key generated based on the unique information of the communication partner received by e-mail and the own information stored in the communication partner itself, and transmitting the encrypted facsimile image data. Features.

In the first invention of such a facsimile apparatus, prior to transmission of facsimile image data to be transmitted, the unique information of the communication partner is received by e-mail, so that the encryption key is obtained based on the two unique information. Is generated. Thereafter, the facsimile image data encrypted with the encryption key generated in this manner is transmitted from the transmission side device by e-mail.

Further, a second embodiment of the facsimile apparatus according to the present invention
The present invention is a facsimile apparatus that receives facsimile image data encrypted with an encryption key based on each unique information of itself and a communication partner from the communication partner as an e-mail, wherein the facsimile device receives the unique The facsimile image data received is decrypted with the encryption key generated based on the information and its own unique information stored therein.

In the second invention of such a facsimile apparatus, prior to the reception of facsimile image data, which should be received, the unique information of the communication partner is received by e-mail, so that the encryption is performed based on the two unique information. A key is generated. Thereafter, the received facsimile image data is decrypted using the previously generated encryption key.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments. FIG. 1 shows a line L1, the Internet (computer network) 100, and the facsimile apparatuses FS and FR according to the present invention connected through the line L1, and here also shows the internal configuration of the transmission-side facsimile apparatus FS. . Although FR indicates a receiving-side facsimile apparatus, both are facsimile apparatuses of the present invention, and have the same basic configuration.

Line L1, Internet 100, Line L
Communication between the facsimile machines FS and FR via
It is performed based on an e-mail protocol such as SMTP and POP3.

The two facsimile apparatuses FS and FR have basically the same configuration. Here, a configuration example of the facsimile apparatus of the present invention will be described using the transmission side facsimile apparatus FR as an example.

The facsimile apparatus FS according to the present invention comprises an MPU
, A scanner 2, a printer 3, an NCU 4, a modem 5, a RAM 6, a network interface 7, and a hard disk (H
D) Hardware elements such as 8 are connected, and the control unit 1 controls each of these hardware elements.

The scanner 2 reads a document, encodes it as dot image data, accumulates and outputs the encoded data. The printer 3 prints out a message received from another facsimile machine.

The NCU 4 is a piece of hardware for closing and opening the public line (PSTN) L2, and connects the modem 5 to the public line L2 as required. Communication via the public line L2 is performed in accordance with ITU recommendation T.30.

The RAM 6 is composed of an SRAM, a flash memory, and the like, and stores temporary data generated during the arithmetic processing of the control unit 1 and data related to transmission and reception. The network interface 7 is an interface for communicably connecting the facsimile machines FS, FR and the line L1.

The HD8 has an ID-NIKS encryption function (hereinafter, referred to as an ID-NIKS encryption function).
An encryption conversion program storage area 8a storing an encryption conversion program used for encryption and decryption using an ID-NIKS function, and the ID (unique information) of the facsimile apparatus FS
Is stored in the ID storage area 8b. In addition,
In addition to the above, various computer programs necessary for various operations of the respective facsimile machines FS are stored in the HD 8 in advance.

The control unit 1 executes the cryptographic conversion program stored in the cryptographic conversion program storage area 8a of the HD 8 to allow the control unit 1 to communicate between itself and another facsimile apparatus, for example, the facsimile apparatus FR.
The encrypted communication of facsimile image data is performed in the form of transmission and reception of e-mail via the Internet. In this case, the facsimile apparatus FS encrypts the facsimile image data to be transmitted by the ID-NIKS function, and transmits the encrypted data to the Internet 100 as an attached file of an e-mail. On the other hand, the facsimile apparatus FR decrypts the encrypted facsimile image data received from the Internet 100 in the form of an attached file of an e-mail by the ID-NIKS function and restores the image data.

FIG. 2 shows the operation of the facsimile apparatus of the present invention having the above-described configuration, particularly the operation at the time of Internet facsimile communication performed via the Internet 100 using the ID-NIKS function. The communication state between the transmission-side facsimile apparatus FS and the reception-side facsimile apparatus FR, in other words, a timing chart illustrating the procedure of the method of the present invention, the transmission facsimile apparatus FS shown in FIG. The operation will be described with reference to the flowchart of FIG. 4 and the flowchart of FIG.

First, when Internet facsimile communication is performed in the transmission-side facsimile apparatus FS, whether or not to use encrypted communication is selected (step S1).
1). If the encrypted communication is selected (YES in step S11), the transmitting-side facsimile apparatus FS itself has the ID-NIK
FIG. 5 shows an example of FIG. 5 having an S function and an ID (unique information) used for generating a common key for encrypted communication by the ID-NIKS function read from the ID storage area 8b of the own HD 8 as contents. Is transmitted to the receiving facsimile machine FR via the Internet 100 (step S12, procedure P1). Thereafter, the transmitting facsimile machine FS enters a state of waiting for reception of a reply mail from the receiving facsimile machine FR (step S13).

In the transmission notification mail shown in FIG. 5, the ID of the transmission-side facsimile machine FS and the content information of the next e-mail to be transmitted are described in the portion of the content next to the header.

If the encryption is not selected (NO in step S11), the transmitting facsimile machine FS immediately converts the facsimile image data into an attached file without performing the encryption (step S21), and proceeds to step S21 described later.
Proceed to step 17.

[0034] The receiving facsimile machine FR receives the mail (YES in step S31), and if it is a transmission notification mail (YES in step S32), the transmitting facsimile machine FS uses the ID-NIKS function from the content. (Step S33: YE
S), that it also has an ID-NIKS function, and that its own H
I for use in generating a common key for encrypted communication by the ID-NIKS function read from the ID storage area 8b of D8
A reply mail having the content D as shown in FIG. 6 is transmitted to the transmission-side facsimile machine FS via the Internet 100 (step S34, procedure P2). Further, the receiving facsimile apparatus FR extracts the ID of the transmitting facsimile apparatus FS included in the transmission notification mail received in step S32, and this ID and its own HD8
A common key is generated based on the ID stored in the ID storage area 8b (step S35).

In the reply mail shown in FIG. 6, the ID of the receiving facsimile apparatus FR and the electronic mail to be transmitted next by the transmitting facsimile apparatus FS can be accepted in the portion of the content next to the header. Is described.

Thereafter, the receiving-side facsimile apparatus FR enters a state of waiting for reception of a transmission mail from the transmitting-side facsimile apparatus FS (step S36). If NO in steps S32 and S33, the receiving facsimile machine FR performs another corresponding process (step S41).

Upon receiving the reply mail transmitted from the receiving facsimile apparatus FR (YES in step 13), the transmitting facsimile apparatus FS determines whether or not the receiving facsimile apparatus FR has the ID-NIKS function. (Step S14).
(YES in 4), retrieves the ID of the receiving facsimile machine FR included in the received reply mail, and generates a common key based on this ID and the ID stored in the ID storage area 8b of its own HD 8 (step). S15).

When the common key is generated in this way, the transmitting facsimile apparatus FS transmits the facsimile image data to the ID.
Specifically, the data is encrypted by the -NIKS function using the encryption conversion program by the ID-NIKS function stored in the encryption conversion program storage area 8a of the HD 8 and attached (step S16). When all the facsimile image data is converted into an attached file, the transmitting facsimile machine FS creates a transmission mail as shown in FIG. 7 and transmits it to the receiving facsimile machine FR (step S1).
7. Procedure P3).

In the outgoing mail shown in FIG. 7, the content information on the attached file is described in the portion of the content next to the header, and the facsimile image data encrypted next is converted from the binary code to the character information. An example of the attached file converted to the code is shown.

When the facsimile apparatus other than the facsimile apparatus of the present invention is the receiving facsimile apparatus, a reply mail of the content indicating that the facsimile apparatus does not have the ID-NIKS function is sent in step S13 to the transmitting facsimile apparatus. Since the FS receives the message, in this case, the processing proceeds in the order of steps S21 and S17 described above, and the ID-N
Internet facsimile communication is performed without using the IKS function, in other words, without encryption.

Thus, the transmitting facsimile machine F
When the receiving-side facsimile apparatus FR receives the transmission mail transmitted from S (YES in step S36), the receiving-side facsimile apparatus FR decrypts the original image data using the previously generated common key (step S36). S37).

[0042]

As described in detail above, according to the facsimile communication method according to the present invention, both the transmitting side device and the receiving side device store their unique information, and the facsimile image data to be transmitted is stored. By transmitting the unique information to each other prior to transmission as an e-mail, an encryption key is generated based on the two unique information, and then the facsimile image data is encrypted with the encryption key thus generated. The file is transmitted as an attached file of the e-mail from the transmission side device, and is received by the reception side device. The reception side device decrypts the received encrypted facsimile image data with the previously generated encryption key. Therefore, a facsimile communication method can be realized in which a common key can always be generated reliably without having to know in advance the unique information of a communication partner, and therefore, Internet facsimile communication can always be performed after encryption.

According to the first aspect of the facsimile apparatus of the present invention, prior to transmitting facsimile image data to be transmitted as e-mail, the unique information of the communication partner is received by e-mail. And generates an encryption key based on its own unique information stored therein, and then encrypts the facsimile image data to be transmitted with the encryption key generated in this way and transmits it as an e-mail attachment. . For this reason, the common key can be always and reliably generated without the need to know in advance the unique information of the destination facsimile machine, and therefore the Internet facsimile communication can be always and reliably performed by encryption. A facsimile apparatus capable of transmitting facsimile image data is realized.

Further, according to the second aspect of the facsimile apparatus according to the present invention, prior to receiving facsimile image data to be originally received as e-mail, it receives the unique information of the communication partner, An encryption key is generated based on the stored unique information, and then the encrypted facsimile image data received as an attached file of the e-mail is decrypted with the encryption key generated earlier. For this reason, the common key can always be generated reliably without the need to know in advance the unique information of the receiving facsimile machine, so that the Internet facsimile communication can always be performed without fail by encryption. A facsimile apparatus capable of receiving the received facsimile image data is realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a facsimile apparatus of the present invention.

FIG. 2 is a timing chart showing a signal transmission / reception state between a facsimile apparatus according to the present invention and a facsimile apparatus on a transmission side and a reception side when both are used.

FIG. 3 is a flowchart showing an operation of the transmission-side facsimile apparatus of the present invention.

FIG. 4 is a flowchart showing the operation of the receiving-side facsimile apparatus of the present invention.

FIG. 5 is a schematic diagram showing an example of a transmission notification mail transmitted from the transmission-side facsimile apparatus of the present invention.

FIG. 6 is a schematic diagram showing an example of a reply mail transmitted from the receiving facsimile apparatus of the present invention.

FIG. 7 is a schematic diagram illustrating an example of a transmission mail transmitted from the transmission-side facsimile apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control part 6 RAM 7 Network interface 8 Hard disk (HD) 8a Encryption conversion program storage area 8b ID storage area 100 Internet FS Sending facsimile apparatus FR Receiving facsimile apparatus

Continued on the front page F term (reference) 5C062 AA02 AA29 AB38 AC34 AF00 BD09 5C075 AB90 CA90 CF90 EE03 5J104 AA01 AA16 EA04 EA26 PA00 PA08

Claims (3)

[Claims] 1. Facsimile image data encrypted with an encryption key based on unique information of both a transmission side device and a reception side device is transmitted as electronic mail from the transmission side device, and decrypted by the reception side device using the encryption key. A facsimile communication method, wherein the two devices mutually notify unique information stored individually by e-mail prior to transmission / reception of image data. 2. A facsimile apparatus for transmitting facsimile image data encrypted with an encryption key based on each unique information of itself and a communication partner to the communication partner as an e-mail, wherein the facsimile apparatus receives the unique information of the communication partner received by e-mail A facsimile apparatus characterized in that facsimile image data to be transmitted is encrypted and transmitted using the encryption key generated based on information and its own unique information stored therein. 3. A facsimile apparatus which receives facsimile image data encrypted with an encryption key based on each unique information of itself and a communication partner from the communication partner as an e-mail, wherein the facsimile apparatus receives the facsimile image data from the communication partner. A facsimile apparatus for decrypting facsimile image data received with the encryption key generated based on unique information and own unique information stored therein.