JPH024188B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an encrypted communication method used in facsimile communication.

Conventional configuration and its problems Conventionally, this type of method has been used in some facsimile devices that require secret communication.The transmitter encrypts all transmitted signals, and the receiver encrypts all transmitted signals. The method used was to decode and reproduce the signals. However, according to this method, communication is usually only possible between special transceivers equipped with an encryption device and decoding device, and communication is only possible between a facsimile device equipped with the above-mentioned encryption device or decryption device and a general facsimile device. To achieve this, a method has been used in which the encryption device or decryption device is manually disconnected using a separately provided switching means.

Purpose of the Invention The present invention has been made in view of the above-mentioned problems, and is such that a facsimile device having an encryption device can automatically communicate with both a facsimile device having a decoding device and a general facsimile device not having a decoding device. The purpose is to provide a cryptographic communication method that allows communication.

Composition of the Invention The present invention communicates without encrypting a communication procedure control signal, and includes information as to whether or not the receiving side is equipped with a decoding device in the communication procedure control signal. We aim to achieve the above objective by only encrypting communications.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an outline of an encrypted communication method according to an embodiment of the present invention, in which 1 is a transmitter;
2 is a receiver, 3 is a reading circuit that converts the optical signal of the transmitted document into an electrical signal, 4 is an encoding circuit that encodes the output signal of the reading circuit 3 to conform to, for example, the communication method of the G3 standard, and 5 is a G3 A communication control circuit that generates and analyzes communication control signals used in standard communication procedures; 6 inputs the output signal of the encoding circuit 4 and the output signal of the communication control circuit 5, and selects one of them; 7 is an encryption circuit that encrypts the output signal of the multiplexer 6 in a fixed manner; 8 is an input circuit that inputs the output signal of the multiplexer 6 and the output signal of the encryption circuit 7, and selectively selects one of them. 9 is a modulation/demodulation circuit that modulates or demodulates the input signal using a G3 standard modulation/demodulation method; 10 and 11 are network control circuits that perform line control; , when the signal indicates that the receiving side is equipped with a decoding device, the multiplexer 8 selects the output of the encryption circuit 7, and when the receiving side does not have a decoding device, the multiplexer 8 selects the output of the multiplexer 6. When the conversion of the signals of the communication procedure between is completed, the selection of the multiplexer 6 is switched from the communication control circuit 5 to the encoding circuit 4, and
13 is a transmitting control circuit which, when a code end signal is input from the encoding circuit 4, switches the selection of the input of the multiplexer 6 to the output of the communication control circuit 5 and at the same time switches the selection of the input of the multiplexer 8 to the output of the multiplexer 6; 14 is a communication control circuit 13 that controls the communication procedure with the machine 1;
A modulation/demodulation circuit 15 modulates the output signal of the network control circuit 10 and demodulates the output signal of the network control circuit 10. A modulation/demodulation circuit 15 modulates either the output signal of the modulation/demodulation circuit 14 or the output signal of the decoding circuit 16 that decodes the encrypted signal. Multiplexer for selective output, 17 is multiplexer 1
The output signal of 5 is sent to the communication control circuit 13 or
A demultiplexer 19 outputs to either of the decoding circuits 18 for restoring encoded data; 19 is a recording circuit;
21 and 22 are signal input terminals, and 23 and 24 are signal output terminals.

The operation of the embodiment configured as above will be explained below.

First, in response to a call from transmitter 1, the line between the transmitter and receiver is connected, and then the transmitter and receiver 2 mutually confirm their transmitting and receiving functions, but at this point, The control circuit 12 includes a multiplexer 6
At the same time, the multiplexer 8 is caused to select the output of the multiplexer 6. On the other hand, in the receiver 2, the control circuit 20 controls the multiplexer 15 to select the output of the modulation/demodulation circuit 14, and controls the demultiplexer 17 to output the input signal to the communication control circuit 13. Therefore, the control signal output from the communication control circuit 5 is inputted to the signal input terminal 22 of the receiver 2 through the line from the signal output terminal 23 without being encrypted, and is then input to the signal input terminal 22 of the receiver 2 and then sent to the decoding circuit 16.
The control signal from the communication control circuit 13 is sent to the line from the signal output terminal 24 via the modulation/demodulation circuit 14 and the network control circuit 11, and from the signal input terminal 21 of the transmitter 1. The signal is input to the communication control circuit 5 via the network control circuit 10 and the modulation/demodulation circuit 9. In this state, a receiving function identification signal indicating the receiving function of the receiver 2 is sent from the communication control circuit 13 to the transmitter 1, but the signal contains information as to whether the receiver 2 has a decoding function. In response, the communication control circuit 5 of the transmitter 1 that receives this input includes information that the mode setting command signal is encrypted before transmission when encrypted communication is to be performed. Send. At the same time, a control signal is output from the communication control circuit 5 to the control circuit 12, and this signal causes the control circuit 12 to temporarily cause the multiplexer 8 to select the output of the encryption circuit 7, and in this state, the communication control circuit 5 sends out a training signal for determining whether the transmission/reception condition is good or not, following the above-mentioned mode setting command signal. On the other hand, if the mode setting command signal includes information to encrypt and transmit, the communication control circuit 13 of the receiver 2 sends the control circuit 20 to the multiplexer 15 to the decryption circuit 16.
The receiver 2 waits in this state.

The training signal from the transmitter 1 is decoded by the decoding circuit 16 via the signal input terminal 22, the network control circuit 11, the modulation/demodulation circuit 14, and then sent to the multiplexer 1.
5. Communication control circuit 1 via demultiplexer 17
Enter 3. If the decoding result of the training signal is good, the communication control circuit 13 sends out a reception preparation confirmation signal, and this signal is sent out to the line via the modulation/demodulation circuit 14, the network control circuit 11, and the signal output terminal 24, and the transmitter 1 The signal is inputted from the signal input terminal 21 of , via the network control circuit 10 and the modulation/demodulation 9, to the communication control circuit 5.

When the communication control circuit 5 receives the reception preparation confirmation signal, it sends a control signal to the control circuit 12, causes the multiplexer 6 to select the output of the encoding circuit 4, and at the same time causes the multiplexer 8 to select the output of the encoding circuit 7. control so that On the other hand, the communication control circuit 1
3 is the control circuit 2 after sending the reception preparation confirmation signal.
0, the multiplexer 15 selects the output of the decoding circuit 16, and the demultiplexer 17 controls the demultiplexer 17 to output a signal to the decoding circuit 18.

At this stage, the reading circuit 3 is activated in accordance with the instruction from the communication control circuit 5 of the transmitter 1, and the photoelectrically converted signal is encoded by the encoding circuit 4, and then sent to the multiplexer 6, the encoding circuit 7, and the multiplexer 8. The signal is then modulated by the modulation circuit 9 and sent out to the line via the network control circuit 10 and the signal output terminal 23, and the signal is sent to the receiver 2.
The signal is input to the decoding circuit 16 via the signal input terminal 22, the network control circuit 11, and the modulation/demodulation circuit 14, and is decoded.
Furthermore, multiplexer 17, demultiplexer 1
7, the signal is converted into an image signal by a restoration circuit 18, and recorded accordingly by a recording circuit 19.

When the image information is completed, the encoding circuit 4 sends a signal to the control circuit 12 to cause the multiplexer 6 to select the output of the communication control circuit 5, and to cause the multiplexer 8 to select the output of the multiplexer 6. 2 also connects multiplexer 1 to control circuit 20.
5 selects the output of the modulation/demodulation circuit 14 and sends the output of the demultiplexer 17 to the communication control circuit 13.
A signal is sent from 8 to the control circuit 20. Therefore, both the transmitter and receiver have an encryption circuit 3 and a decryption circuit 1.
Communication ends with 6 disconnected.

Effects of the Invention As is clear from the above description, the present invention communicates without encrypting the control signal of the communication procedure, and information on whether the receiver is equipped with a decryption device or not is included in the communication procedure control signal. Encrypted communications are carried out only when the receiver has a decryption device, including
Since it is determined whether or not to encrypt image information using an unencrypted communication procedure control signal, it is possible to automatically perform communication regardless of whether the receiver has a decryption device or not.

Furthermore, by encrypting and transmitting the training signal before the transmitter encrypts and transmits the image information, it is possible to determine whether the receiver's decoding means are good or not. Abnormalities that occur when decoding can be prevented.

[Brief explanation of drawings]

The drawing is a block diagram of a communication device using the encrypted communication method according to the present invention. 1... Transmitter, 2... Receiver, 4... Encoding circuit, 5, 13... Communication control circuit, 6, 8, 15...
...Multiplexer, 7...Encryption circuit, 9,14
...Modulation/demodulation circuit, 12, 20...Control circuit, 16
...Decoding circuit, 17...Demultiplexer, 18
...Restoration circuit.

Claims (1)

[Claims] 1. Information as to whether the receiver has decryption means is included in the reception function identification signal in the communication procedure control signal generated after the line connection between the transmitter and the receiver, and when the receiver has the decryption means, , the receiver that has sent out the reception function identification signal waits in a state where the received signal is decoded through the decryption means, and the transmitter that has received the reception function identification signal determines whether the transmission and reception conditions are good or not. A training signal to be determined is encrypted and transmitted, the receiver decodes the encrypted training signal, and if the decoding result of the training signal is good, it transmits a reception readiness confirmation signal, and the transmitter decodes the encrypted training signal. An encrypted communication method in which image information is encrypted and transmitted after receiving a reception preparation confirmation signal, and the receiver decodes and reproduces the encrypted image information.