JPH06303227A - Method for establishing synchronization of privacy communication - Google Patents

Abstract

PURPOSE:To provide the synchronization establishing method of privacy communication, which establishes the synchronization of the start and the end of suitable privacy communication. CONSTITUTION:At the time of starting the privacy communication of a sound channel and a data channel between a terminal #(i) and a terminal #(j), a privacy communication start message is transmitted to the terminal #(j) at the data channel from the terminal #(i). The terminal #(j) transmits a privacy communication reception message to the terminal #(i). The terminal #(i) is set to be a privacy communication state and the transmission-side of the sound channel is set to be the privacy communication state. When the terminal #(j) detects the privacy communication state, the transmission-side of the data channel and that of the sound channel are set to be the privacy communication state. When the terminal #(i) detects the privacy communication state, a privacy communication start completion message is transmitted to the terminal #(j).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for establishing synchronization of confidential communication, and more particularly to the start and end of confidential communication which is suitable when voice information and data information are simultaneously transferred using a digital transmission line. The present invention relates to a method for establishing synchronization of confidential communication between terminal devices for establishing synchronization.

[0002]

2. Description of the Related Art There is confidential communication as a security measure for digital communication. In confidential communication, the encryption algorithm used by the sender and the receiver is set to be the same in advance, the encryption key used for confidential communication is shared with each other, and the confidential communication is started or ended at a certain time. Is common.

In the above confidential communication step, there are FE # iL, DES, etc. as the encryption algorithm used, and as the encryption key sharing method, the terminal-to-terminal key sharing method and the center key using the center. Delivery methods have been proposed (for details, refer to the document "Revised text of CD 9
798-2 “Entity authentication mechanisms, Part 2:
Entity authentication using symmetric techniques ”
ISO / IEC / DP 9798-2: 1990 (E) ").

Further, as a method for establishing synchronization of secret talk start / end in communication of stream data such as voice using a digital transmission path, a secret talk communication device (Japanese Patent Application No. 2-1
92514), at the start of the confidential communication, the transmitting side sets a specific bit pattern indicating the start of the confidential communication to the confidential communication state after sending, and the receiving side specifies the confidential communication start sent from the transmitting side. If a bit pattern of is detected, there is a method of setting a secret communication state.

On the other hand, as a method for establishing synchronization of start / end of confidential communication of data information, a unit of encryption processing of data information is a physical layer like voice information, and is regarded as stream data, and synchronization similar to voice information is performed. Possible establishment methods.

[0006]

However, in the method for establishing the synchronization of the start / end of the confidential communication of the data information as described above, since the encryption / decryption processing is performed on the digital information itself of the physical layer, it is performed on the transmission line. When a bit error occurs, synchronization processing and error correction in the data link layer may not be possible.

For example, when the HDLC (High level DataLink Controller) procedure is adopted as the protocol of the data link layer, frame synchronization is performed by the F pattern forming the frame. When FEAL is used as the encryption algorithm, a 1-bit error on the transmission path expands to 64 bits as the decryption result depending on the encryption mode, and the F pattern itself becomes erroneous.
Occasionally, the synchronization process cannot be performed.

When the ISDN line is used as the digital transmission line, when the exchange needs to interpret the contents of the information channel when the encryption / decryption processing is performed on the physical layer information of the data information (for example, This method cannot be applied to communication by packet switching). Therefore, it is necessary that the encryption processing target of the data information is more than the information part of the data link layer (for details, refer to the document "Tanaka et al., PC expansion board for ISDN multimedia encrypted communication, IEICE technical research report, OS91-64"). , 1992 "), but in this case, there is a drawback that a method for establishing synchronization of encryption processing for stream data such as audio information cannot be adopted.

The present invention has been made in view of the above points,
Solving the above conventional problems, using a digital transmission line,
An object of the present invention is to provide a method for establishing synchronization of confidential communication, which establishes suitable synchronization of start and end of confidential communication when voice information and data information are simultaneously transferred.

[0010]

FIG. 1 is a diagram (No. 1) for explaining the principle of the present invention.

According to the present invention, in the confidential communication of voice using a digital transmission line, at the start of the confidential communication, the transmitting side sends a specific bit pattern and then enters the confidential communication state, and the receiving side detects a specific bit pattern, Synchronize the confidential communication of voice calls by setting the confidential communication, and when the confidential communication ends, the sender sends a specific bit pattern and then enters the normal communication state, and the receiving side detects the specific bit pattern and then enters the normal communication state. When starting confidential communication of voice channels and data channels between the terminal device #i and the terminal device #j, the terminal device #i sends a confidential communication start message on the data channel to the terminal device #j. (Step 1), and when the confidential communication start message is received from the terminal device #i on the data channel of the terminal device #j, the voice channel is received. After the side is set to a state in which the confidential communication can be accepted (step 2), the confidential communication acceptance message is transmitted to the terminal device #i through the data channel (step 3), and the terminal device #j is transmitted through the data channel of the terminal device #i. When the confidential communication start acceptance message from the device is received, the receiving side of the voice channel is set to the confidential communication accepting state (step 4), and then the data channel is set to the confidential communication state (step 5) and the transmitting side of the voice channel is set. Is set to the confidential communication state (step 6), and when the receiving side of the voice channel of the terminal device #j detects the confidential communication state (step 7), the data channel is set to the confidential communication state (step 8), and then the voice channel When the transmission side of the device is set to the confidential communication state (step 9) and the reception side of the voice channel of the terminal device #i detects the confidential communication state (step 10), The privacy communication start completion message using the channel terminal device #
j (step 11), and the terminal device #j receives the confidential communication start completion message on the data channel to establish synchronization of confidential communication start in the confidential communication system.

FIG. 2 shows a diagram (No. 2) for explaining the principle of the present invention.

According to the present invention, when the confidential communication end message is transmitted from the terminal device #i to the terminal device #j via the data channel (step 21) and the confidential communication end message is received from the terminal device #j via the data channel. , The receiving side of the voice channel is set to the normal communication acceptable state (step 22).
Then, the confidential communication end acceptance message is transmitted to the terminal device #i via the data channel (step 23), and the terminal device #i is transmitted.
When the confidential communication end acceptance message is received on the data channel in i, the voice channel receiving side is set to the normal communication acceptable state (step 24), and then the data channel is set to the normal communication state and the voice channel transmitting side is set. When the terminal device #j detects the normal communication state in the voice channel receiving side in the normal communication state (step 25), the data channel is set in the normal communication state (step 25), and then the voice channel transmitting side is set. Normal communication state (step 2
6) When the terminal device #i detects the normal communication state on the receiving side of the voice channel (step 30), it uses the data channel to send a confidential communication end completion message to the terminal device #j.
(Step 31), and the terminal device #j receives the confidential communication end message on the data channel to establish the synchronization of the confidential communication end in the confidential communication system.

[0014]

According to the present invention, when confidential communication is performed between the terminal device #i and the terminal device #j by using the digital transmission line, when the confidential communication is performed after the voice channel and the data channel are set up. The device #i sends a "secret communication start message" to the partner terminal device #j on the data channel.
When the terminal device #j receives the "secret communication start message" on the data channel, the receiving side of the voice channel is set to "acceptable communication acceptance state", and then the "secret communication acceptance message" is transmitted on the data channel to the terminal device. Send to #i. When the terminal device #i receives the "secret communication start acceptance message" on the data channel, the receiving side of the voice channel is set to the "secret communication acceptable state", and then the data channel is set to the "secret communication state". When the transmission side of the voice channel is set to “secret communication state”, and when the terminal device #j detects “confidential communication state” on the reception side of the voice channel, the data channel is enabled for secret communication, and then voice communication is performed. The transmission side of the channel is set to the "secret communication enabled state". Finally, the "secret communication start completion message" is transmitted from the terminal device #i to the terminal device #j using the data channel, so that the synchronization of the secret communication start in the confidential communication system is established.

Further, in the present invention, when the confidential communication is completed, the terminal device #i sends a “secret communication completion message” to the terminal device #j through the data channel. Terminal #
When the "confidential communication end message" is received at j, the receiving side of the voice channel is set to the "confidential communication end acceptance state", and then the "confidential communication end acceptance message" is transmitted to the terminal device #i through the data channel. When the terminal device #i receives the "secret communication end acceptance message", the receiving side of the voice channel is set to "private communication end acceptable state", and then,
The data channel is set to "normal communication state" and the transmitting side of the voice channel is set to "normal communication state". Terminal #
When the "normal communication state" is detected on the receiving side of the voice channel at j, the data channel is enabled for confidential communication, and then
The transmitting side of the voice channel is set to "normal communication state". Finally, the confidential communication end completion message is transmitted from the terminal device #i to the terminal device #j using the data channel to establish the synchronization of the confidential communication end in the confidential communication system.

With this configuration, when the confidential communication of the voice information and the data information is performed between the terminal device #i and the terminal device #j using the digital transmission line, the start / end of the confidential talk of the data information can be easily performed. Synchronization can be established.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

In the description of the present invention, ISDN is used as the digital transmission line, but it is of course applicable to digital transmission lines other than ISDN.

FIG. 3 is a block diagram of a system using the confidential communication method according to an embodiment of the present invention. In the figure, the terminal device 1 is connected to a subscriber line of an ISDN basic interface. The switching device 2 accommodates a plurality of ISDN basic interface subscriber lines.

In the example of the figure, the terminal device 1 is an ISDN.
A terminal control unit 11 that performs layer 1 to layer 3 control of a subscriber line and network control of an upper layer above layer 4; an encryption mechanism 12; a data information control unit 13; a voice information control unit 14; The information input unit 15 is included.

FIG. 4 is a diagram for explaining cryptographic communication according to an embodiment of the present invention. The example shown below is a case where the terminal device 1 # i of FIG. 3 performs normal communication with the terminal device 1 # j.

Terminal device 1 connected to the ISDN subscriber line
#J shows a procedure (hereinafter, abbreviated as a call connection procedure) for calling the terminal device #i of the communication partner to perform the circuit connection call connection.
That is, the call connection is "SET" from the terminal device 1 # i of the caller.
An UP "(call setup request) message is sent to the switching device 2 to be started. The switching device 2 starts the receiving side terminal device 1 #.
Send a "SETUP" message to j. Exchange device 2
Means "C # iLLPROC", which has meaning during call setup processing
(Call Proceeding: notification during processing for call setup) is sent to the terminal device 1 # i, and when the call of the called party starts,
A "#iLERT"(#ilerting: notification that the called party is ringing) message is sent to the calling party. Next, when the called party answers, "CONN" (Connect # icknowledge: CONN
Message is sent to the called side, the connection of the #j channel is completed, and the communication starts (for details, refer to, for example, the document “Supervised by Akiyama, ISDN picture book reader” pages 92-101 Ohmsha, 1988 issue. ).

In the normal communication, if the call setup is completed in the sequence shown in FIG. 4, the terminal device #i and the terminal device #j can communicate with each other. However, in the case of secret communication, the terminal device #i is set after the call setup. It is necessary to synchronize the start / end of confidential communication between i and the terminal device #j.

FIG. 5 shows a confidential communication protocol for voice information (in the case of confidential communication). It is a method for establishing synchronization of secret communication of voice using a digital transmission line. That is, the terminal device #
i and the terminal device #j perform confidential communication, the terminal device #i
Is a special code "ID" that is not normally used in the digital transmission line on the transmitting side to establish synchronization at the start of encryption.
A plurality of "L" are transmitted, and then one "EOC" code indicating the end of "IDL" is transmitted, after which the terminal device #i sets the communication mode of the transmission side to confidential communication (encryption). On the other hand, in the terminal device #j, a plurality of "ID
If one "EOC" is received after receiving "L", the communication mode on the receiving side is set to confidential communication (decoding).
The synchronization between the transmission side of j and the reception side of the terminal device #i is the same as the above-described method as shown in FIG. Further, the synchronization at the time of changing from the confidential communication to the normal communication is performed by the same method.

Next, FIG. 6 is a diagram for explaining a synchronization establishing method at the start of confidential communication according to an embodiment of the present invention.

Step 61) At the start of confidential communication, the terminal device #i transmits a confidential communication start message to the terminal device #j using the data channel.

Step 62) When the terminal device #j receives the confidential communication start message transmitted from the terminal device #i, the terminal device #j sets the receiving side of the voice channel to the voice confidential talk start detectable state.

Step 63) The terminal device #j notifies the terminal device #i that the preparation for the confidential communication is completed.
The confidential communication start acceptance message is transmitted to the terminal device #i using the data channel, and whether or not the terminal device #i starts the confidential communication for the transmitting side of the voice channel (corresponding to the receiving side of the terminal device #j). Monitor.

Step 64) When the terminal device #i receives the confidential communication start acceptance message transmitted from the terminal device #j, the terminal device #i starts the confidential communication for the data channel (encrypts the transmitting side and the receiving side). To decrypt). Next, the terminal device #i sets the receiving side of the voice channel to the voice secret talk startable state.

Step 65) The terminal device #i instructs (encrypts) the start of the confidential voice communication with respect to the transmission side of the voice channel, and the terminal device #j transmits to the transmission side of the voice channel (the reception side of the terminal device #i). Correspondence) to monitor whether the confidential communication has started.

Step 66) When the terminal device #j detects that the terminal device #i has started the confidential communication with respect to the receiving side of the voice channel being monitored, the terminal device #j has the confidential communication with respect to the receiving side of the voice channel. Is started (decrypted). Further, the confidential communication is started for the data channel (the transmitting side is encrypted and the receiving side is decrypted).

Step 67) The terminal device #j gives an instruction (encryption) to start the confidential voice communication for the transmitting side of the voice channel.

Step 68) When the terminal device #i detects that the terminal device #j has started the confidential communication with respect to the receiving side of the voice channel being monitored, the terminal device #i has the confidential communication with respect to the receiving side of the voice channel. Is started (decrypted).

Step 69) The terminal device #i transmits a confidential communication start completion message to the terminal device #j using the data channel.

Step 70) The terminal device #j receives the confidential communication start completion message transmitted from the terminal device #i. After that, confidential communication is performed in the data channel and the voice channel.

Next, FIG. 7 is a diagram for explaining a synchronization establishing method at the end of confidential communication according to an embodiment of the present invention.

Step 81) At the end of the confidential communication, the terminal device #i transmits the confidential communication end message to the terminal device #j using the data channel.

Step 82) The terminal device #j receives the confidential communication end message transmitted from the terminal device #i,
Set the receiving side of the voice channel to the state where the end of voice confidential talk can be detected.

Step 83) The terminal device #j notifies the terminal device #i that the preparation for the confidential communication is completed.
The confidential communication end acceptance message is transmitted to the terminal device #i using the data channel, and whether or not the terminal device #i terminates the confidential communication for the transmitting side of the voice channel (corresponding to the receiving side of the terminal device #j). Monitor.

Step 84) Terminal device #i is terminal device #
When the confidential communication end acceptance message transmitted from j is received, the confidential communication for the data channel is terminated (transmission / transmission /
(Normal communication with the receiving side). In addition, the terminal device #i sets the receiving side of the voice channel to the voice confidential talk end detection state.

Step 85) The terminal device #i gives an instruction (normal communication) to the end of the voice confidential communication to the transmitting side of the voice channel, and the terminal device #j transmits to the transmitting side of the voice channel (the receiving side of the terminal device #i). Correspondence) to monitor whether the confidential communication has ended.

Step 86) When the terminal device #j detects that the terminal device #i has ended the confidential communication for the receiving side of the monitored voice channel, the terminal device #j ends the confidential communication for the receiving side of the voice channel (normal communication). Then, the confidential communication for the data channel is terminated (normal communication with the transmitting / receiving side).

Step 87) The terminal device #j gives an instruction (normal communication) to end the confidential voice communication with respect to the transmitting side of the audio channel.

Step 88) When the terminal device #i detects that the terminal device #j has ended the confidential communication for the receiving side of the monitored voice channel, the terminal device #i ends the confidential communication for the receiving side of the voice channel (normal communication). ) Do.

Step 89) The terminal device #i transmits a confidential communication end completion message to the terminal device #j using the data channel.

Step 90) The terminal device #j receives the confidential communication completion message sent from the terminal device #i.

After that, normal communication is performed on the data channel and the voice channel.

[0048]

As described above, according to the present invention, according to the synchronization establishment method for confidential communication, voice information and data information are transmitted between the terminal devices #i and #j by using the digital transmission line. When performing the confidential communication of the above, it is possible to easily establish the synchronization of the start / end of the confidential information of the data information by using the confidential information synchronization establishing method of the voice information.

[Brief description of drawings]

FIG. 1 is a diagram (No. 1) for explaining the principle of the present invention.

FIG. 2 is a diagram (part 2) for explaining the principle of the present invention.

FIG. 3 is a block diagram of a system using a confidential communication method according to an embodiment of the present invention.

FIG. 4 is a diagram for explaining cryptographic communication according to an embodiment of the present invention.

FIG. 5 is a diagram showing a confidential communication protocol of voice information (in the case of starting confidential communication).

FIG. 6 is a diagram for explaining a method of establishing synchronization at the start of confidential communication according to an embodiment of the present invention.

FIG. 7 is a diagram for explaining a method of establishing synchronization at the end of confidential communication according to an embodiment of the present invention.

[Explanation of symbols]

 1 Terminal Device 2 Switching Device 11 Terminal Control Unit 12 Cryptographic Mechanism 13 Data Information Control Unit 14 Voice Information Control Unit 15 Voice Information Input Unit

Claims (2)

[Claims] 1. In confidential communication of voice using a digital transmission line, at the start of confidential communication, the transmitting side sends a specific bit pattern and then enters a confidential communication state, and the receiving side detects a specific bit pattern and then performs confidential communication. When the confidential communication ends, the transmitting side sends a specific bit pattern, then enters the normal communication state, and the receiving side detects the specific bit pattern and then enters the normal communication state to synchronize the confidential communication of voice calls. In the device, when the confidential communication of the voice channel and the data channel is started between the terminal device #i and the terminal device #j, a confidential communication start message is transmitted from the terminal device #i on the data channel. When the terminal device #j receives the confidential communication start message on the data channel from the terminal device i, the receiving side of the voice channel is protected. After enabling the speech communication acceptance state, the confidential communication acceptance message is sent to the terminal device #i on the data channel.
To the terminal device #i on the data channel.
When the confidential communication start acceptance message from j is received,
The receiving side of the voice channel is set to a state in which the confidential communication can be accepted,
Next, the data channel is set to the confidential communication state, the transmission side of the voice channel is set to the secret communication state, and when the reception side of the voice channel of the terminal device #j detects the secret communication state, the data channel is set to the confidential communication state. When the confidential side communication state is set, then the transmitting side of the voice channel is set to the confidential state communicating state, and when the receiving side of the voice channel of the terminal device #i detects the confidential state communication state, the confidential channel communication is performed using the data channel. Secret communication characterized by establishing synchronization of secret communication start in the confidential communication system by transmitting a start completion message to the terminal device #j and receiving the confidential communication start completion message on the data channel at the terminal device #j. Communication synchronization establishment method. 2. When the terminal device #i sends a confidential communication end message on the data channel to the terminal device #j, and when the terminal device #j receives the confidential communication end message on the data channel. , After the reception side of the voice channel is set to the normal communication acceptable state, the confidential communication end acceptance message is transmitted to the terminal device # on the data channel.
When the terminal device #i receives the confidential communication end acceptance message on the data channel, the reception side of the voice channel is set to the normal acceptance state, and then the data channel is set to the normal communication state. In addition, the transmission side of the voice channel is set to the normal communication state, and when the terminal device #j detects the normal communication state on the reception side of the voice channel, the data channel is set to the normal communication state, and then the voice channel is set. When the terminal device #i detects the normal communication condition on the receiving side of the voice channel, it transmits a confidential communication start / end message to the terminal device #j using the data channel. , The terminal device #j receives the confidential communication end message on the data channel to establish synchronization of the confidential communication end in the confidential communication system. The method for establishing synchronization of confidential communication according to claim 1.