JPH10200519A - Communication terminal device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To communicate cipher text and a key of cryptogram through different routes for enhancing the confidentiality of communication by sending cipher text through a computer communication network and on the other hand, performing cipher communication that sends a key of cryptograph through a public line. SOLUTION: A facsimile equipment on a sending end sends cipher text that is enciphered by an enciphering part through an internet (#02), when there is a transmission instruction with a start key operation, etc., (#01), and sends a key of a cryptograph that was used for encryption through a telephone line (#03). On the other hand, when a receiving end receives (#11) the key of the cryptogram through the telephone line, it automatically receives (#12) the cipher text through the internet, an enciphering part decodes it by using the key of cryptogram that receives the cipher text, and a recording part prints and outputs (#13) it. Here, when a key of the cryptogram is received through a telephone line, with this reception as a turning point, the receiving end automatically is connected to an internet and receives the cipher text.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a communication terminal device such as a facsimile device capable of communicating with a computer communication network.

[0002]

2. Description of the Related Art Computer communication networks such as the Internet tend to be used more and more, and recently, the number of people who use them also in general homes is increasing. The use of such a computer communication network can reduce the communication time because the user only has to bear the communication cost from the personal computer or the like to the nearest contract provider (connection company to the computer communication network). Communication with overseas computers is now cheaper.

[0003] In view of such circumstances, communication terminal devices such as facsimile devices capable of connecting to a computer communication network have been developed at present. Facsimile transmission,
Alternatively, it can be transmitted to the other party's communication terminal device by any of e-mail transmission. That is, when facsimile transmission is selected when transmitting image data, the image data is directly transmitted using a telephone network or the like. On the other hand, when e-mail transmission is selected, the image data is converted into e-mail format, this data is stored in a mailbox on the network, and many of the receiving parties use a dial-up connection at an appropriate time. A computer communication network is connected via a telephone line, and if e-mail is transmitted, image data is read from a mailbox.

[0004] With the spread of such devices and communication networks, a large amount of image data communication has become possible. On the other hand, information security measures have become an issue.
To solve this, cryptographic communication has been conventionally used.

[0005]

However, in the above-mentioned conventional communication terminal device, if encryption communication is performed through a computer communication network, even if the data amount is large or long-distance communication is performed, the communication cost is not required. However, the transmission of an encrypted text obtained by encrypting transmission data and an encryption key (decryption key) for decrypting the encrypted text are still the same, and various routes are used in a computer communication network. However, there still remains a problem in terms of confidentiality such as data leakage during transmission and wiretapping.

In view of the above circumstances, the present invention has been proposed with the object of providing a communication terminal device in which ciphertext and an encryption key are communicated through different routes, thereby further enhancing the security of communication. You.

[0007]

According to the first aspect of the present invention, there is provided a communication terminal device capable of connecting a computer communication network and a public line network, via a computer communication network. It is characterized by performing cipher communication by communicating an encryption key via a public line network while communicating cipher text.

Here, the encryption key includes an encryption key in a narrow sense used for performing the encryption processing and a decryption key used for performing the decryption processing. In the present invention, the wording of the encryption key is:
It is mainly used in the sense of a decryption key, and it is assumed that both have the same data content. However, these may have different contents, in which case the decryption key is communicated through the public line network.

In this communication terminal device, at the time of transmission, a ciphertext that has been subjected to encryption processing using an encryption key is transmitted through a computer communication network, and the encryption key is transmitted through a public line network. After decrypting the cipher text received through the computer communication network with the encryption key received through the public network, predetermined processing such as printout is performed.

The communication terminal device according to the present invention corresponds to a facsimile device with an e-mail function capable of connecting to a computer communication network, a personal computer having a data communication function, and the like. The computer communication network includes the Internet and personal computer communication services such as NIFTY-Serve and PC-VAN. The e-mail service is implemented as one of the services. On the other hand, the public network includes a telephone network and an ISDN (Integrated Services Digital Network).

In the communication terminal device according to the second aspect, the encryption key is received by polling reception or confidential reception via the public line network. Here, the polling reception is a function of making a transmission request from the reception side and receiving data set on the transmission side, and the confidential reception is a method of temporarily storing the received data in a memory, and storing a predetermined password. Is a function that prevents the stored data from being retrieved unless the user inputs the.

According to the third aspect of the present invention, when the communication terminal device receives the encryption key via the public line network, it automatically connects to the computer communication network and receives the cipher text. That is, it can be seen that the ciphertext has already been transmitted by receiving the encryption key. Therefore, even when the Internet is used for a dial-up connection, the ciphertext can be received immediately after the ciphertext is transmitted.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of the internal configuration of the communication terminal device of the present invention. here,
1 shows a configuration example of a facsimile apparatus with an e-mail function, which is one of the communication terminal apparatuses of the present invention. That is, this facsimile apparatus has a conventional G3, G4
In addition to the facsimile communication function described above, a communication function via a computer communication network is provided. In the following, a description will be given of using the Internet for the computer communication network and using an electronic mail (e-mail) service on the Internet. .

The CPU 1 not only controls each unit of the facsimile apparatus through the bus 12, but also performs various operations such as encryption (decryption), encoding / decoding, image conversion, binary text conversion, and mail editing, which will be described later. Execute the process. The reading unit 2 reads a document with a CCD or the like and outputs black and white binary image data. The recording unit 3 includes a printer of an electrophotographic system or the like, and records (prints and outputs) image data received from another G3 or G4 facsimile machine or via the Internet. The display unit 4
It has a liquid crystal display device and the like, and displays the operation state and image data of the facsimile device. The operation unit 5 includes various keys such as ten keys, speed dial keys, and one-touch dial keys, and performs various input settings for the facsimile apparatus.

The ROM 6 stores software necessary for the operation of the facsimile machine. The RAM 7 stores temporary data generated during execution of the software, and also stores various tables T1 to T3 described later.
The image memory 8 is composed of a DRAM or the like, and stores image data. DSU (Data line terminator: Digi
The tal service unit 9 converts transmission / reception data and voltage so that the digital line L1 using the baseband transmission method can be connected. The modem 10 is a conventional FA
It has a data modem function in addition to the X modem function. N
A CU (Network Control Unit) 11 closes and opens the analog line L2.

FIG. 2 schematically shows the data flow in the facsimile apparatus shown in FIG. In this figure, parts corresponding to those in FIG. 1 are denoted by the same reference numerals. Although an e-mail conversion unit A, an encryption unit 20, an encoding / decoding unit 21, and an auto dialer 25, which will be described later, do not exist in FIG.
It shall be processed by PU1.

The e-mail converter A includes an image converter 22, a binary / text converter 23, and a mail editor 2.
In addition to the facsimile communication, it is possible to access the Internet and use an e-mail service by providing the conventional facsimile apparatus with the e-mail conversion unit A. Encryption unit 20
Represents the image data (plaintext) read by the reading unit 2,
The data is encrypted using a predetermined encryption key or decrypted and output from the recording unit 3. In addition, DES (Data Encryption Standard) or RSA
More specifically, for example, a predetermined bit string represented by “0” and “1” is used as an encryption key, and an operation such as multiplication of the bit string with image data is performed. Hereinafter, the image data thus encrypted is referred to as “encrypted data”.

The encoding / decoding section 21 converts the encrypted data into M
Encoding or decoding is performed by an encoding method such as H, MR, MMR, or the like. Hereinafter, data encoded by these encoding methods is referred to as “encoded data”. The encoded data is stored in the image memory 8. Note that, here, a case where the encrypted data is converted to the encoded data is shown, but the present invention is not limited to this, and the encoded data may be encrypted. In that case, FIG.
The blocks of the encryption unit 20, the encoding / decoding unit 21 and the image memory 8 in FIG.

The image conversion unit 22 converts the encoded data into a TIFF (Tagged Image F), which is a general image format used by a computer, at the time of sending an e-mail.
ile format), and at the time of reception, from TIFF to encoded data. TIFF is published by adobe, and defines various classes that handle not only black and white binary but also black and white multi-valued and full color. One of them is Clas, which handles facsimile images.
s F is defined, and for encoded data,
By adding Class F TIFF header information, T
Can be converted to IFF. Hereinafter, the encoded data to which the Class F TIFF header information is added is referred to as “TIFF data”.

The binary / text converter 23 converts binary data into text data when transmitting an electronic mail, and converts text data into binary data when receiving an electronic mail. In some cases, computers that cannot handle binary data e-mails are connected to the Internet. To ensure that e-mails reach the recipient, binary data such as TIFF data must be It needs to be converted to text data when sending.

Text data handled on the Internet is:
Documents issued by IETF (Internet Engineering Task Fore), RFC (Request For Comments) 82
2, it is defined as a 7-bit code, but MIME (Multipurpose Internet Mail Extension)
If base64 or the like in s) is used, binary data can be converted to text data. It should be noted that base64 is 8 bits x 3 bytes of binary data of 6 bits x
This is an encoding method in which binary data is converted into text data by regarding each byte as a character code and assigning a character code to each byte.

The mail editing section 24 adds mail header information to the TIFF data converted to text data and edits the data into an e-mail format when transmitting the e-mail. The header information is removed and used as TIFF data of text data. Here, the mail header information refers to predetermined header information of an electronic mail on the Internet, and includes "From:", "To:", "Subj" at the beginning of the TIFF data to be transmitted.
It is stipulated that items such as "ect:", "cc:", and "Date:" be added.

The auto dialer 25 sends the dial number read from the provider table T2 and the destination table T3 to the DSU 9, the modem 10 or the N
Send dial number data to CU11. Next, RAM7
FIG. 3 shows the configuration of each table T1 to T3 stored in FIG.
It will be explained together.

In the user table T1 of FIG. 3A, a user ID and password for logging in to the Internet, an e-mail address, and a provider type are registered for each user who uses the facsimile machine. Note that the provider type corresponds to the provider type in the provider table T2 in FIG. In the provider table T2 of FIG. 3B, the provider name, the line type (analog or digital), and the dial number (telephone number) of the provider used when connecting to the Internet are registered in correspondence with the provider type. I have. As a result, a different login procedure can be identified and executed for each provider, and even if one user uses a plurality of providers or the provider has a plurality of lines, this table T2 can be used. Can be handled by setting.

In the destination table T3 of FIG. 3C, a destination name, an e-mail address, a facsimile number and its type (G3 or G4) are registered for each speed dial number and one-touch dial number. Each of the tables T1 to T3 can also output a list of setting contents excluding a secret matter such as a password from the recording unit 3 or the display unit 4, so that each of the tables T1 to T3 by a user or an administrator can be output. Settings, changes, and confirmation work are simplified.

With the above configuration, this facsimile apparatus performs encrypted communication with higher confidentiality than the conventional one. An example of the operation at this time is schematically shown in FIG. In the facsimile apparatus on the transmission side, when a transmission instruction is issued by operating a start key or the like, the original data (encrypted text) encrypted by the encryption unit 20 is transmitted over the Internet, and the encryption key used for encryption is transmitted to a telephone line. Transmission is performed through L1 and L2 (# 01 to # 03).

On the other hand, when the receiving side receives the encryption key via the telephone lines L1 and L2, it automatically receives the cipher text via the Internet, and the encryption unit 20 uses the encryption key having received the cipher text. The data is decrypted and printed out (printed) from the recording unit 3 (# 11 to # 13). Here, when the encryption key is received via the telephone lines L1 and L2, which are public telephone networks, this triggers the automatic connection of the Internet, which is a computer communication network, to receive the ciphertext. ing. Thereby, even when the Internet is used by the dial-up connection method, if the encryption key is received, it is known that the cipher text has already been transmitted, and rapid data transmission can be realized.

The encryption key is communicated with a new signal of the same type as a relay broadcast instruction signal for performing broadcast transmission from a relay station, which has been conventionally transmitted / received by facsimile communication, or in a communication procedure. It is communicated by including it as a new item in NSF (non-standard function identification signal) or the like. Next, the configuration of a communication network provided with the facsimile apparatus is shown in FIG.
Shown in Here, the operation will be described below assuming that F in the figure corresponds to this facsimile apparatus with an e-mail function, but the communication terminal apparatus of the present invention may be a personal computer PC connected by a dedicated line, According to this, data communication can be performed in real time without performing a dial-up connection periodically or at any time.

When performing an encrypted communication from the facsimile apparatus F to the other party's facsimile apparatus with an e-mail function Fa or a personal computer PCa, first, before transmitting the encryption key, an encrypted text is transmitted by e-mail. Calling the contract provider via the public network P,
A computer communication network N is connected, and image data scanned and scanned is transmitted (route-).

Subsequently, the encryption key is transmitted via the public line networks P and Pa (routes ~~, ~~). Since the cipher text has already been sent by e-mail to the other party's facsimile machine Fa and computer PCa, at the same time as receiving the encryption key or at any time thereafter,
A computer communication network N is connected via the public line network Pa, and an e-mail addressed to its own address is received (from route to
, ~), And the ciphertext can be decrypted.

If communication is performed in such a form, cipher text having a large data amount is transmitted / received through the computer communication network N, so that both the transmitting side F, the receiving side Fa, and the PCa pay communication costs up to the contract provider. Just need
Normal facsimile communication (route ~~, ~~
, ~~) does not require much communication cost as in the case of sending and receiving ciphertext. Note that Fb in the figure is a normal facsimile machine without an e-mail function.

Since a computer PC is connected to the computer communication network N by a dedicated line connection, and another network Na is connected to the computer communication network N by a LAN connection or the like,
From the facsimile machine F to the computer P connected to a dedicated line
C, E-mail can also be sent to LAN-connected network Na (routes ~~, ~~).
In this case, the computer PC and the network N
If the public line networks P and Pa are connected to a, encrypted communication similar to the above can be performed.

Next, the basic operation of the communication terminal apparatus (facsimile apparatus with an e-mail function) at the time of reception will be described with reference to the flowchart of FIG. Here, first, the encryption key is confidentially received via the public line networks P and Pa (steps 100 to 106). If the reception of this encryption key is confirmed, the Internet is accessed by dial-up connection and the cipher text is transmitted. Receive (Step 107)
To 121).

When a call arrives for a confidential transmission instruction, the received encryption key data is stored in a confidential box (RAM 7) designated by the transmission side. Then, the line is released, and the reception of the confidential message is recorded by the recording unit 3 together with the destination and the confidential box number, or displayed on the display unit 4. After that, when a password (password) corresponding to the confidential box is input, the recording section 3 records the fact that the communication is encrypted communication to the display section 4 so that only the person who input the password can recognize it. It is displayed (steps 100 to 106).

Next, the person who has confirmed the encrypted communication first selects data such as his / her user ID from the user table T1 by operating the operation unit 5 or the like in order to receive the cipher text which is the text. Then, the line type of the provider to be connected is read from the provider table T2, the modem 10 is set for an analog line, the DSU 9 is set for a digital line, and the provider's telephone number is called. Then, the reception of the e-mail (ciphertext) is started.

Here, the reception of the e-mail depends on the protocol, for example, PAP (Password Authentication Protocol).
ol) and log in using POP (Post Office Prot
ocol). Subsequently, the e-mail header is removed from the received e-mail data by the e-mail editing unit 24, converted to binary data by the binary / text conversion unit 23, and returned from the TIFF data to encoded data by the image conversion unit 22. After the encoded data is decoded by the encoding / decoding unit 21, the data is decoded by the encryption unit 20 by using the encryption key which has been confidentially received. This decrypted image data is
The recording is performed by the recording unit 2 or displayed on the display unit 4, and then the line is released (step 107).
~ 121).

Although the case where the encryption key is received by confidential reception has been described above, the present invention can also receive the encryption key by polling reception (transmission request reception). Polling reception refers to operation of the operation unit 5 or
By specifying the time, a transmission request is made from a reception side to a predetermined communication terminal apparatus (transmission side), and data set (stored in a memory) on the transmission side is received. According to this, it is possible to receive the encryption key at any time after receiving the ciphertext via the computer communication network N and start decryption (decryption) of the ciphertext.

It should be noted that the present invention can take embodiments other than those described above, and the data to be transmitted in the computer communication network N may be data such as audio and moving images in addition to the image data (for example, the Internet). WW
W), a computer communication network other than the Internet (e.g., NIFTY-Serve) may be used to transmit the e-mail.

[0039]

As can be understood from the above description, according to the communication terminal device of the first aspect of the present invention, when performing cryptographic communication, ciphertext is transmitted via a computer communication network. The communication cost can be remarkably reduced, and the encryption key is communicated via a public line network which is a different route from the ciphertext, so that the confidentiality of the communication is further improved as compared with the related art.

According to the communication terminal device of the second aspect,
Since the encryption key is received by polling reception or confidential reception, communication with secrecy can be performed.
According to the communication terminal device of the third aspect, by receiving the encryption key, it can be determined that the cipher text has already been transmitted, and the computer communication network can be automatically connected to receive the cipher text. Therefore, even when a computer communication network is used by dial-up connection, data can be transmitted quickly.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of an internal configuration of a communication terminal device according to the present invention.

FIG. 2 is a schematic diagram showing a flow of data in a communication terminal device according to the present invention.

FIG. 3 is a diagram showing an example of a configuration of a table stored in a communication terminal device according to the present invention.

FIG. 4 is a flowchart schematically showing an operation of the communication terminal device according to the present invention.

FIG. 5 is a diagram illustrating an example of a configuration of a communication network including a communication terminal device according to the present invention.

FIG. 6 is a flowchart illustrating an example of a basic operation at the time of reception of the communication terminal device according to the present invention.

[Explanation of symbols]

 Reference Signs List 20: encryption unit A: electronic mail conversion unit N: computer communication network P, Pa: public line network F: facsimile machine with electronic mail function

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04M 11/00 303 H04L 11/20 101B H04N 1/44

Claims (3)

[Claims] 1. A communication terminal device capable of connecting a computer communication network and a public line network, wherein an encrypted text is communicated via the computer communication network and an encryption key is communicated via the public line network. A communication terminal device for performing encrypted communication. 2. The method according to claim 2, wherein the encryption key is transmitted via the public network.
The communication terminal device according to claim 1, wherein the communication terminal device receives the data by polling reception or confidential reception. 3. When the encryption key is received via the public network, the computer communication network is automatically connected,
The communication terminal device according to claim 1, wherein the communication terminal device receives the ciphertext.