JPS59223076A - Cipher communication method - Google Patents

Abstract

PURPOSE:To automatically perform communication with a communication procedure control signal which is not ciphered irrespectively of whether or not a receiver is equipped with a cipher decoder, by including information indicating that whether or not the receiver is equipped with a cipher decoding device in the communication procedure control signal, and performing ciphered communication only when the receiver is provided with the decoder. CONSTITUTION:In response to a call from a transmitter 1, the circuit between the transmitter and a receiver 2 is connected and the transmitting function and receiving function of the transmitter 1, and receiver 2 are mutually confirmed. Then a control signal outputted from a communication controlling circuit 5 is inputted into the signal input terminal 22 of the receiver 2 from a signal output terminal 23 through the circuit without being ciphered and further inputted into a communication controlling circuit 13 without passing through a decoding circuit 16. A receiving function discriminating signal including information indicating that whether the receiver 2 is equipped with a cipher decoding function or not, is transmitted from the communication controlling circuit 13 to the transmitter 1. Upon receiving the discriminating signal, the communication controlling circuit 5 of the transmitter 1 sends a mode setting instruction signal including information indicating that ciphered transmission is performed as the response. When the information indicating that ciphered transmission is performed is included in the mode setting instruction signal, the communication controlling circuit 13 of the receiver 2 controls a multiplexer 15 so as to select the output of the decoding circuit 16.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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 machines that require secret communication.The transmitter encrypts all transmitted signals, and the receiver encrypts all of these 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 a decoding device, and communication is only possible between a facsimile machine 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.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is a facsimile machine having an encryption device, a facsimile machine having a decoding device, and a general facsimile device having a decoding device. It is an object of the present invention to provide an encrypted communication method that can automatically communicate with both facsimile machines.

Structure 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 attempt to achieve the above objective by only encrypting communication.

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 an optical signal of a transmission document into an electrical signal, and 4 is a reading circuit for converting an optical signal of a transmission document into an electric signal. an encoding circuit that encodes the output signal of the reading circuit 3 to conform to, for example, a G3 standard communication method; 5 a communication control circuit that generates and analyzes a communication control signal used in the G3 standard communication procedure; 6 is a multiplexer that inputs the output signal of the encoding circuit 4 and the output signal of the communication control circuits and selectively outputs one of them, and 7 is an encryption circuit that encodes the output signal of the multiplexer 6 in a fixed manner. , 8 is a multiplexer that inputs the output signal of the multiplexer 6 and the output signal of the encryption circuit 7 and selectively outputs one of them;
modulates the input signal using the 03 standard modulation/demodulation method,
Alternatively, the modulation/demodulation circuit for demodulation, 10.11 is a network control circuit for line control, and 12 is the output signal of the communication control circuit 5. If the signal indicates that the receiving side is equipped with a decoding device, it is sent to the multiplexer 8. If the receiving side does not have a decoding device, the output of the multiplexer 6 is selected; however, the selection of the multiplexer 6 is communicated when the exchange of signals in the communication procedure between the transmitter and receiver is completed. When switching from the control circuit 5 to the encoding circuit 4 and inputting a code end signal from the encoding circuit 4, the selection of the output of the multiplexer 6 is switched to the output of the communication control circuit 6, and at the same time the output selection of the multiplexer 8 is switched. 13 is a communication control circuit that controls the communication procedure with the transmitter 1; 14 is a modulation/demodulation circuit that modulates the output signal of the communication control circuit 13 and demodulates the output signal of the network control circuit 1o. , 15 is a multiplexer that selectively outputs either the output signal of the modulation/demodulation circuit 14 or the output signal of the decoding circuit 16 that decodes the encrypted signal. 17 is a multiplexer that outputs the output signal of the multiplexer 15 for communication control. A demultiplexer 19 outputs to either the circuit 13 or a restoration circuit 18 for restoring encoded data, and a recording circuit 20 outputs the output signal from the communication control circuit 13 to the multiplexer 15 and the demultiplexer 1.
A control circuit controls the selection of the output of 6, 21.22 is a signal input terminal, and 23.24 is a signal output terminal.

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 causes the multiplexer 6 to select the output of the communication control circuit 5, and simultaneously causes the multiplexer 8 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 1γ to output the input signal to the communication control circuit 13. Therefore, the control signal output from the communication control circuit 5 is not encrypted and sent to the signal output terminal 2.
3 to the signal input terminal 22 of the receiver 2 through the line, and input to the communication control circuit 13 without passing through the decoding circuit 16. The control signal from the communication control circuit 13 passes through the modulation/demodulation circuit 14 and the network control circuit 11. is sent to the line from the output terminal 24,
The signal is input from the signal input terminal 21 of the transmitter 1 to the communication control circuit 5 via the network control circuit 16 and the modulation/demodulation circuit 9.

In this state, a reception function identification signal is sent from the communication control circuit 13 to the transmitter 1, which indicates the reception function of the receiver 2. The communication control circuit 5 of the transmitter 1, which has received this information, sends out the signal including information that the mode setting command signal is encrypted and transmitted as a response. At the same time, a control signal is output from the communication control circuit 6 to the control circuit 12, but this signal (the control circuit 12 causes the multiplexer 8 to temporarily select the output of the encryption circuit 7, and in this state, the communication control Following the mode setting command signal, the circuit 5 sends out a training signal for determining whether the transmission/reception condition is good or not.On the other hand, the communication control circuit 13 of the receiver 2 transmits a code into the mode setting command signal. If the information includes the information to decode and transmit, the control circuit 20 controls the multiplexer 16 to select the output of the decoding circuit 16, and the receiver 2 waits in this state. .

The training signal from the transmitter 1 is input to the signal input terminal 22.
to the decoding circuit 1 via the network control circuit 11 and the modulation/demodulation circuit 14.
The signal is decoded at 6 and input to the communication control circuit 13 via a multiplexer 15 and a demultiplexer 17. If the analysis result of the training signal is good, the communication control circuit 13 sends out a reception preparation confirmation signal, and the 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 from the signal input terminal 21 of the network control circuit 10. When the communication control circuit 5 inputs the reception preparation confirmation signal, the communication control circuit 5 inputs the reception preparation confirmation signal to the communication control circuit 5 through the change 1" key 9.
2, the multiplexer 6 is controlled to select the output of the encoding circuit 4, and at the same time, the multiplexer 8 is controlled to select the output of the encoding circuit 7. On the other hand, after transmitting the reception preparation confirmation signal, the communication control circuit 13 causes the control circuit 2° to cause the multiplexer 15 to select the output of the decoding circuit 16, and causes the demultiplexer 17 to select the output of the decoding circuit 18.
At this stage, the reading circuit 3 is activated according to instructions from the communication control circuit 6 of the transmitter 1, and the photoelectrically converted signal is encoded by the encoding circuit 4, and sent to the multiplexer 6 and the encoder. The signal is modulated by the modulation circuit 9 via the conversion circuit 7 and the multiplexer 8, and is sent out to the line via the network control circuit 10 and the signal output terminal 23. 14, the signal is input to the decoding circuit 16, where it is decoded, further passed through the multiplexer 17 and demultiplexer 17, converted into an image signal by the restoration circuit 18, and recorded accordingly in the recording circuits 1 and 9. 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 causes the control circuit 2o to cause the multiplexer 15 to select the output of the modulation/demodulation circuit 14 and send the output of the demultiplexer 17 to the communication control circuit 13 from the restoration circuit 18 that has detected the end of the image information to the control circuit 20. A signal is sent out.

Therefore, both the transmitter and receiver have an encryption circuit 3 and a decryption circuit 16.
The communication will end with the connection disconnected.

Effects of the Invention As is clear from the above explanation, the present invention communicates without encrypting the communication procedure control signal, and includes information on whether or not the receiver is equipped with a decryption device in the communication procedure control signal. Encrypted communication is carried out only when the receiver has a decryption device, including a decryption device. This has the effect that communication can be performed automatically regardless of whether the person has a decoding device or not.

[Brief explanation of the drawing]

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] A receiving function identification signal in a communication procedure control signal generated after line connection between the transmitter and receiver includes information as to whether the receiver has a decryption means, and when the receiver has the decryption means, The receiver that has sent the receiving function identification signal waits in a state where the received signal is decoded through the decryption means, and the transmitter that has received the receiving function identification signal encrypts the image information and sends it out. In this encrypted communication method, the receiver decodes and reproduces the encrypted image information.