JPH0244832A - Communication system - Google Patents

Abstract

PURPOSE:To reduce cost of the system by providing a ciphering/decoding device only at the end of a communication terminal connection side in respective transmission lines. CONSTITUTION:Designation information of a communication terminal 1a on a reception side and information to be transmitted are sent from a communication terminal 10a on a transmission side. With sending information whether ciphering/decoding is necessary or not to a switching means 5a in the middle of connection with the designated terminal, the relaying ciphering/decoding device 9 on the way of the transmission line 8 is turned on/off. At the time of ciphering communication with a communication terminal 6a which is directly connected with the switching means 5a, the relaying ciphering/decoding device 9 is turned on and is turned off in the other cases. Thus, a ciphering/decoding operation is executed only once between the communication terminal 10a on the transmission side and the communication terminal 1a on the reception side when information is ciphered and transmitted. Consequently, is comes to be unnecessary to respectively provide the ciphering/decoding devices on both ends of the transmission lines. Only the ciphering/decoding devices 9 and 2 can be provided on the end of the communication terminal connection side of respective transmission lines 3 and 8 and one device 40 in a relaying point. Thus, cost can be reduced.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides an encrypting device and a decrypting device for encrypting and transmitting information, even over multiple transmission sections to be encrypted. The present invention relates to a communication system that can reduce the number of conversion devices.

(Conventional technology) For important communications or communications that require secrecy, transmission data sent from a communication terminal is encrypted and transmitted over a transmission path, and the receiving side decrypts it and outputs it to the receiving terminal. Is there a way to send and receive data? In this case, conventionally, an encryption/decryption device is connected to each communication terminal, and the transmitted data from the communication terminal on the sending side is encrypted by the encryption/decryption device on the communication terminal and sent out to the transmission path. On the receiving side, the transmitted data is decrypted by its own encryption/decryption device, the data is restored, and the data is output to the receiving communication terminal. This makes it possible to maintain the confidentiality of data during transmission.

Here, an example of the configuration of a conventional system of this type is shown in FIG. In FIG. 3, 1 and 6.10 are communication terminals, and 3 and 8 are transmission lines.

These communication terminals 1, 6, 10 are connected via transmission lines 3, 8. 2. 4. 7. ' 9 is an encryption/decryption device, which is connected to the input/output end of the transmission line 3 and 8, respectively, and encrypts information to be sent from the communication terminal and sends it to the transmission line, and encodes information received from the transmission line. is decrypted and given to the communication terminal.

5 is an information switching device, which connects the plurality of communication terminals 1゜6.
10, the communication terminal on the sending side performs switching control in order to connect the communication terminal on the sending side and the other communication terminal specified by the communication terminal.

In the configuration shown in the figure, a communication terminal l.

6 are connected to the information switching device 5 via transmission lines 3 and 8 by encryption/decryption devices 9 and 8, respectively, and the communication terminal 6 is directly connected to the information switching device 5.

Therefore, the information switching device 5 is connected to the transmission lines 3 and 8 via the encryption/decryption devices 4 and 7, respectively.

In such a configuration, if information is to be transmitted from the communication terminal 1 to the communication terminal 6, the information is transmitted from the communication terminal l together with the designation information of the communication terminal 6, but the information transmitted from the communication terminal 1 is After being encrypted by the encryption/decryption device 4 connected to the communication terminal 1, it is sent to the information switching device 5 via the transmission path 3. Then, the information switching device 5 decrypts it in the encryption/decryption device 4 on the transmission path 3 side, and the information switching device 5 knows from the designation information of the other party terminal in this received information that the communication is for the communication terminal 6, and communicates. A terminal 6 is selected and the previously decoded transmission information is sent to that communication terminal 6.

On the other hand, in the case of communication from communication terminal 1 to communication terminal 10,
The information is again encrypted by the encryption/decryption device 7 and sent via the transmission path 8 to the encryption/decryption device 9 of the communication terminal 10, where it is decrypted and then sent to the communication terminal 10.

In this way, conventional systems are configured so that encryption/decryption devices are installed at both ends of each transmission section, and the encryption/decryption is repeated for each transmission section before being sent to the other party. Ta.

According to this conventional method, as the number of transmission sections increases, encryption/decryption devices must be installed at both ends of each transmission section, which requires a large number of encryption/decryption devices and increases the cost of the system. There is a problem that there is no such thing.

(Problem to be Solved by the Invention) As mentioned above, there is a communication method that encrypts the transmitted information on the transmission path so that it is not known to a third party during transmission, but the conventional In this type of system, an encryption/decryption device is provided at the input/output end of a transmission line, and the transmitted information is encrypted when sent out to the transmission line, and decoded when taken out from the transmission line. This is because the configuration is such that encryption/decryption is performed uniquely. Therefore, in conventional systems, if there are multiple transmission lines, an encryption/decryption device must be installed for each transmission line. This increases the cost of the system.

Therefore, an object of the present invention is to provide a communication system in which information is encrypted and transmitted, and information is decrypted and received to keep the information confidential on the transmission path. An object of the present invention is to provide a communication system in which the number of encryption/decryption devices can be reduced and the cost of the system can be reduced.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention is configured as follows. That is, it has a plurality of transmission paths, each transmission path is connected via a relay point, and the relay point is connected to the designated communication terminal and the transmission side communication terminal based on the destination communication terminal designation information from the transmission side communication terminal. A switching means for connection is provided to selectively connect, and information transmitted between communication terminals in multiple systems is encrypted and transmitted by encryption/decryption devices provided at the input and output ends of the transmission path, and the information is decrypted. In a communication system in which information is encrypted on a transmission path by receiving it as a In addition to adding a function to output control information, a relay encryption/decryption device is provided that controls the encryption/decryption function to be turned on/off using this input/off control information.
Each transmission path is configured such that an encryption/decryption device is provided only at the communication terminal connection side end.

(Function) This system with such a configuration has a function of controlling whether or not to encrypt or decrypt information by determining whether or not the other party's communication terminal to which information is to be transmitted has an encryption/decryption device. It is a must have. In the present invention, the sending side communication terminal sends the specification information of the receiving side communication terminal and the information to be transmitted, and by sending the information on whether or not encryption/decryption is necessary to the switching means when connecting with the specified terminal, the transmission path Turn on/off the intermediate relay encryption/decryption device. Then, the relay encryption/decryption device is turned on during encrypted communication with a communication terminal directly connected to the switching means, and turned off at other times to encrypt and transmit information. In this case, encryption/decryption is performed only once between the sending communication terminal and the receiving communication terminal.Therefore, there is no need to provide encryption/decryption devices at both ends of the transmission path as in the past.
It is sufficient to simply provide one at each communication terminal connection side end of each transmission path and one at the relay point.

Therefore, it becomes possible to reduce the cost of the system.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a block diagram showing an embodiment of the present invention.
Moreover, FIG. 2 is a detailed system configuration diagram of the I
a, 6a, 1. oa is a communication terminal, and 3
．． 8 is a transmission line. These communication terminals 1a, 6a,
10a is configured to be connected and transmitted via transmission lines 3 and 8.

2.9.40 are encryption/decryption devices, respectively. Of these, the encryption/decryption devices 2 and 9 are connected to the transmission paths 3 and 8.
The information transmitted from the communication terminals is encrypted by encryptors 2a and 9a and sent to the transmission path, and the information received from the transmission path is decrypted by decryptors 2b and 9b. digitized and given to the communication terminal. Further, the encryption/decryption device 40 is for relaying and is connected to the information switching device 5a.

The information switching device 5a selects a plurality of communication terminals 1. a, 6a10
Among a, the relay point performs switching control to connect the transmitting side communication terminal and the other party communication terminal specified by the transmitting side communication terminal, and also uses the encryption/decryption necessity information given from the communication terminal. It has a function of providing "on, off" control information to the encryption/decryption device 40 for use in accordance with the content of the necessity information. In the configuration shown in the figure, the communication terminals 1a and 6a are encrypted/decrypted devices 9 and 6a, respectively.
8 is connected to the information switching device 5a via the transmission line 3.8, and the communication terminal 6a is directly connected to the information switching device 5a. Then, the information switching device 5a encrypts/
It has a decoding device 40 for relaying, and the transmission path 3,
The connection structure is such that information exchange with 8 is performed via this encryption/decryption device 40. Further, the relay encryption/decryption device 40 outputs control information of the encryption/decryption device 40 from the controller 40a, and the controller 40a of the encryption/decryption device 40 receives this control information. In response, the encoder 40b and the decoder 40c are turned on (ie, in an active state) and turned off (in other words, in an inactive state). In addition, each communication terminal 1a, 8a, 10a
Since the above-mentioned necessity information is outputted from the transmitter and does not have an encoding/encryption device, the configuration is such that the necessity information of encoding/encryption is outputted at the time of transmission.

In such a configuration, from the communication terminal 1a to the communication terminal 6
When transmitting information to communication terminal a, communication terminal 1a to communication terminal 6
Send selection designation information for a. As a result, the information switching device 5
a selects and connects to the communication terminal 6a.

Next, the communication terminal 6a on the receiving side sends necessity information indicating whether its own encryption/decryption is necessary, and the information switching device 5a uses this necessity information to encrypt the "in" control information for relaying. /output to the decryption device 40.Then, this encryption/decryption device 40 uses an encoder 40b and a decryptor 40c by the controller 40a.
Turn on. As a result, the information from the communication terminal 1a and the information from the communication terminal 6a are encrypted/decrypted by the encryption/decryption devices 2 and 40, and the transmission path 3 used by the communication terminal 1a and the communication terminal 6a is Encryption/decryption is performed in this interval.

Next, when it is desired to transmit information from the communication terminal 1a to the communication terminal 10a, the communication terminal 1a sends designation information for the communication terminal 10a. Based on this designation information, the information switching device 5a selects and connects to the communication terminal 10a.

Further, the communication terminal 10a outputs "off" control information to the relay encryption/decryption device 40 based on the necessity information.

Then, this encryption/decryption device 40 turns off the encoder 40b and decryptor 40c using the controller 40a.

As a result, the relay encryption/decryption device 40 stops functioning, and the information from the communication terminal 1a and the information from the communication terminal 10a are encrypted/decrypted by their own encryption/decryption devices 2 and 9, respectively. This means that encryption/decryption will not be performed in the middle.

Similarly, information can be transmitted from the communication terminal 6a to the communication terminal 1a or from the communication terminal 10a to the communication terminal 1a using the same procedure, but in this case, the necessity information is sent to the communication terminal 6 on the sending side.
It will be transmitted from a or lOa.

In this way, this system has the function of controlling whether or not to encrypt or decrypt information by determining whether or not encryption/decryption is necessary for the communication terminal of the other party to which information is to be transmitted. In the present invention, the sending communication terminal sends the specification information of the receiving communication terminal and the information to be transmitted, or the information on whether or not encryption/decryption is necessary is sent to the switching means when connecting with the specified terminal. , the relay encryption/decryption device in the middle of the transmission path is turned on/off. When performing encrypted communication with a communication terminal directly connected to the switching means, the relay encryption/decryption device is turned on and otherwise turned off, encrypting and transmitting the information. In this case, encryption/decryption is performed only once between the sending communication terminal and the receiving communication terminal, so it is necessary to provide encryption/decryption devices at both ends of the transmission path as in the past. Instead, it is sufficient to simply provide one at each communication terminal connection side end of each transmission path and at the relay point.

In this way, by installing an encryption/decryption device that can control encryption/decryption operations at the relay point, it is only necessary to install it on the transmission path on the communication terminal connection side. Since it is possible to transmit information using
The number of encryption/decryption devices can be significantly reduced compared to the conventional method, and the cost of the system can be significantly reduced.

It should be noted that the present invention is not limited to the nine embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.For example, in the above embodiment, one transmission section may be added. Although the above example has been described, it can be similarly applied to other cases. Furthermore, although the above-mentioned necessity information is automatically sent from the receiving side communication terminal, it may be sent manually or may be sent from the sending side. Furthermore, the necessity information is output only when there is no need for encryption/decryption, and the information switching device outputs an "in" control signal only when receiving this necessity information, and otherwise outputs an "off" control signal. ” control signal may be output.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to provide a communication system in which the number of encryption/decryption devices can be significantly reduced compared to the conventional system, and the cost of the system can be significantly reduced. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram for explaining an embodiment of the present invention, FIG. 2 is a block diagram showing details thereof, and FIG. 3 is a block diagram for explaining a conventional example. 1610・Communication terminal, 2. 8.4.0... Encryption/decryption device, 2a, 9a, 4 (lb Encryptor, 2
b, 9b40c...decoder, 3, 8/transmission line, 5
a, 5... Information switching device, 40a... Controller.

Claims (1)

[Claims] It has a plurality of transmission lines, each transmission line is connected via a relay point, and the relay point connects the designated communication terminal and the transmitting side communication terminal based on the destination communication terminal designation information from the transmitting side communication terminal. A switching means is provided to selectively connect, and information transmitted between communication terminals in a plurality of systems is encrypted and transmitted by an encryption/decryption device provided at each input and output end of the transmission path, and the information is decrypted. In a communication system in which information is encrypted on a transmission path upon reception, the switching means has "on"/"off" control based on information sent from the communication terminal indicating whether or not encryption/decryption is necessary. In addition to adding a function to output information, a relay encryption/decryption device is installed that controls the encryption/decryption function to be turned on or off using this “in” or “off” control information, and each transmission 1. A communication system characterized in that an encryption/decryption device is provided only at the end of the communication terminal connection side.