JPS61253953A - Transmission system for synchronizing supervisory signal - Google Patents

Abstract

PURPOSE:To insert an enciphering device to a general communication circuit to use the communication circuit also for cipher communication by forming packet data from a synchronizing supervisory signal through a packet exchange or a packet multiplying device and sending the packet data to a transmission line. CONSTITUTION:Packet multiplying processing and packet exchanging processing of a synchronizing supervisory signal inputted through a console unit 7-N are executed prior to inputs obtained from other console units and the processed signal is supplied to the enciphering device 10. The device 10 digitally adds a pseudo random code counted up by a prescribed clock to the inputted packet data to be enciphered over the whole bits to encipher the packet data and supplies the enciphered packet data to a MODEM 11. The MODEM 11 sends the input to a telecommunication line 1101 as a modulated wave based upon a prescribed method. Thus, the data bit rates on the input and outputs sides of the enciphering device 10 can be held at the completely same state by converting the synchronizing supervisory signal into the packet data through the packet exchange or the packet multiplying device and transferring the packet data in a packet exchange network.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a synchronization supervisory signal transmission system, and in particular to a synchronization supervisory signal for monitoring cryptographic synchronization in the transmission and reception of encrypted communications via a packet switching network. This invention relates to a synchronization monitoring signal transmission method.

[Conventional technology]

Packet switching systems are well known these days. This exchange method is a branch of the store-and-forward method, in which data sent from a terminal device is temporarily stored in the exchange and then transferred at high speed within the exchange network to be delivered to the terminal device of the communication partner. The data is divided into a certain length and treated as packet data in which a header containing information such as destination information, error control information, transfer order number, etc. is added to the beginning of each divided block.

The basic configuration of the packet switching network includes a packet switching I&A% having a switching function, a packet multiplexing device having a packet assembly/disassembly function for general terminals, and a traffic convergence function.

Packet switching equipment sets communication routes, assembles or disassembles data from non-packet terminals into packet data format, and manages and controls the system, and packet multiplexing equipment converts data from a large number of terminals into packet data formats. Concentration of multiplexing in packet format on the communication line with the exchange, and assembly and disassembly of packets for accommodating non-packet terminals, similar to the 4C packet exchange, are performed at a lower level than the packet exchange.

In addition to being capable of multiplexed communications, such packet-switched networks have various advantages such as improved line utilization efficiency, communication between different types of terminals, and reduced bit error rate. Increasingly, encrypted communications designed to conceal the contents of communications are also being carried out via this packet switching network.

In encrypted communication carried out via a packet-switched network, multiple pieces of data are sent to the packet switch from each small terminal device at random in time, either directly or via a packet multiplexing device. Of the input data, data that requires encryption is often converted into packet data and provided to the sending-side encryption device in a separate process such as priority reception. The sender's cryptographic device adds a synchronization monitoring signal for cryptographic synchronization monitoring to this encrypted packet data and sends it to the receiving cryptographic device via a dedicated cryptographic communication line, and the receiving side transmits the data via this synchronization monitoring signal. A common communication method is to perform reception processing while checking the synchronization of the encryption signal with the encryption device on the other side.

In the conventional synchronous supervisory signal transmission method of this type, the synchronous supervisory signal, which is not necessary for sending and receiving encrypted packet data, is multiplexed directly onto the encrypted communication line within the transmitting cryptographic device via a packet switch or packet multiplexing device. The system uses a format in which the multiplexed data is separated and used within the receiving cryptographic device.

FIG. 2 is a block diagram showing the basic configuration of a conventional synchronous supervisory signal transmission system.

The conventional synchronous supervisory signal transmission system shown in FIG. Encryption devices 112 and 5, modem 3
and 4 etc.

A message to be encrypted, which is input via the packet multiplexing device or directly from the terminal device to the packet switching device IK, is converted into packet data and then encrypted in a predetermined format by the encryption device 2. This encryption is usually performed by digitally adding a pseudo-random number code that advances at a preset clock to packet data as digital data.

Packet data encrypted by the encryption device 2 is sent via the modem 3 as a modulated wave in a predetermined format to an encrypted communication line 301 serving as a transmission path. For example, the synchronized monitoring signal is combined with the data frame of each packet data transmitted in this manner, multiplexed in a format such as round head data, and transmitted directly from the encryption device 2. The encrypted packet data modulated wave including the synchronization monitoring signal is demodulated by the modem 4 and supplied to the encryption device 5.The encryption device 5 receives the encryption while monitoring the encryption synchronization via the synchronization monitoring signal and decrypts it. It is then sent to the packet switch 6. The packet switch 6 decomposes the packet data into ThK before assembling the packet data, and then supplies it to the terminal device of the encrypted communication destination. Currently, the standard communication speed between the encrypting device 2 and the encrypting device 5 is A.
(bps, bit/3) and the overconfidence speed of the synchronization monitoring signal is B (bps), it is clear that the packet data output from the packet switch 1 must be set to the communication speed of A-B (bps). be. For example, when A is 2400 (bps) and B is 10 (bps), the input side of the encryption device 20 is 239°bps, and the output side is 24°bps.
The communication speed is 00bps. In some cases, the synchronization monitoring signal is formed isometrically by deleting data in a specific digit of the data frame without preparing the data bits for the synchronization monitoring signal, but in any case, the 20 cryptographic devices and the output The data bit rates on both sides differ by the amount of the synchronization monitoring signal.

On the other hand, in the cryptographic device 5, the communication speed is A on the input side and A-B on the output side.

[Problem that the invention seeks to solve]

As mentioned above, in the conventional synchronous supervisory signal transmission method, the input and output communication speeds of a pair of cryptographic devices that perform bidirectional communication must differ by the amount of the synchronous supervisory signal, so general communication using a packet switching network It has the disadvantage that it is extremely difficult to use it for encrypted communication by interposing an encryption device in the line in terms of system configuration, and the hardware and software are also extremely complicated. SUMMARY OF THE INVENTION An object of the present invention is to provide a synchronous supervisory signal transmission system that eliminates the above-mentioned drawbacks.

[Means for solving problems]

The method of the present invention is a synchronization monitoring signal transmission method for transmitting a synchronization monitoring signal for monitoring cryptographic synchronization in cryptographic overconfidence in which packet data to be transmitted/received via a packet switching network is encrypted and transmitted/received. The synchronous supervisory signal transmitting means assembles the data into packet data via a packet switch or a packet multiplexing device and sends the data to a transmission path.

〔Example〕

Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an embodiment of the synchronous supervisory signal transmission system of the present invention.

The vehicle or terminal equipment 7-1 and 7-2 of the embodiment shown in FIG.
7-N, packet multiplexer 8. Packet switch9. Encryption device lo, modem 11.12° Encryption device 13. Packet switch 14. packet multiplexer 15,
and terminal equipment 16-1.16-2,...16
-N, etc.

Inputs from the terminal devices 7-1 to 7-N, including terminal devices for encrypted communication, are supplied to the packet switch 9 via the packet multiplexer fi18. In this embodiment, the signal is supplied to the packet switch via the packet multiplexer, but there is no problem in inputting the signal directly to the packet switch. Which one to use can be arbitrarily determined by taking into account conditions such as the operational scale of the packet switching network, the number of terminal devices, and the amount of data to be processed.

The packet multiplexing device 8 receives data from the terminal devices 7-1 to 7-N, and the encryption device 10 also receives the synchronization monitoring signal via the terminal device that specifies it in advance, in the case of the present embodiment, the terminal device 7-N. These are input, multiplexed in packet format, and sent to the communication line 801. In this way, the synchronization monitoring signal is also carried as packet data in the communication cycle $801.

In this case, the above-mentioned synchronization monitoring signal is used in the encryption devices 10 and 13 to synchronize and monitor the pseudo-random number codes necessary for input encryption and decoding, and is generated in both encryption devices while maintaining synchronization. Cryptographic synchronization is confirmed by monitoring the synchronization of the same pseudo-random number code on the receiving side.

For this synchronization monitoring signal, bit values of the pseudo-random code generated by the sending-side cryptographic device 10 are extracted and used at preset intervals t. Further, the timing of extraction every t is set based on the timing of pseudo random number code generation, as will be described later.

Packet data sent via the communication circuit @801 is supplied to the packet switch 9. This packet switch 9 also has a store-and-forward function, and performs assembling and forwarding of upper-level packets containing data from other packet multiplexers or terminal equipment groups (none of which are shown). In this embodiment, the synchronization monitoring signal input via the terminal device 7-N is sent to the floor system flltlo after undergoing packet multiplication processing and packet switching processing which are given priority over inputs from other terminal devices. is supplied to Further, data input from terminal devices other than the terminal device 7-N is supplied to the encryption device 10 using other time slots of the above-described preferential packet multiplexing and exchange processing. In this way, the staircase @
The packet data supplied from the IOK is packet-multiplexed data in a preset format and must be encrypted, including a synchronization monitoring signal.

The encryption device 10 encrypts the input packet data to be encrypted by digitally adding a pseudo-random code that is stepped at a predetermined clock over all bits, and supplies the encrypted packet data 903 to the modem IIK.

The modem lla input is sent to the communication line 1101 as a modulated wave according to a predetermined method.

In this way, the synchronization monitoring signal is converted into packet data via a packet switch or a packet multiplexer and transferred within the exchange network (bucket) 35, and H is the data bit rate on the input/output side of the cryptographic device 100. It is possible to maintain exactly the same state. When the modem 12 inputs the transmitted take, it demodulates it and supplies it to the encryption device 13.

The cryptographic device 113 has the same pseudo-random code generation circuit and digital addition circuit as the cryptographic device 10, and monitors the cryptographic synchronization as follows. Perform decryption processing. In this embodiment, as described above, encryption is performed by a method in which a preset pseudo-random number code is digitally added to packet data while incrementing at a predetermined clock timing. The cryptographic device 13 that received this is the cryptographic device 10
The same content as the generated pseudo-random code is generated while maintaining synchronization, and this is subjected to exclusive digital addition (EX-OR).
) to remove the encryption. As described above, the reference timing for generating the synchronization monitoring signal is set in accordance with the timing of pseudo-random number generation for sending and receiving while maintaining synchronization.

ζ The decrypted packet data is supplied to the packet multiplexer 15 via the packet switch 14, where it undergoes demultiplexing processing and is sent to a predetermined destination terminal device, in the case of this embodiment, the terminal. Equipment 16-1 to l6-
NK is supplied. The terminal device l6-N)ζ also outputs a demultiplexed synchronization monitoring signal, which is supplied to the encryption device 13.

Pseudo-random number code and cryptographic device 1 with a built-in cryptographic system kl 3a synchronization supervisory circuit and used in the above-mentioned decryption process
Monitors synchronization with the pseudo random number code generated. This synchronization has been confirmed in the @le communication episode! It can be assumed that the decryption is performed correctly except for the occurrence of errors related to the above.

The synchronization monitoring circuit extracts random number bits from the pseudo-random code generated by the cryptographic device 130 every t times at the same extraction timing as the cryptographic device IO, and stores them in the built-in memory. In other words, the random numbers and data stored in this way are exact copies of the synchronization monitoring signal output from the cryptographic device IO, including the timing of occurrence.

The synchronization monitoring circuit also stores in its memory the demultiplexed synchronization monitoring signal sent from the terminal device 16-N.

This synchronization monitoring signal is supplied to the encryption device 13 with a delay corresponding to the time required for packet processing in the packet switching network on the transmitting side and the receiving side. Therefore, once this is stored in memory, compare it with a copy of the synchronization monitoring signal that is stored separately.) It is possible to make a comparison that eliminates the influence of delays caused by the processing time of the packet switching network. Compare and verify the synchronization supervisory signal sent from the transmitting side with the copy of the synchronization supervisory signal stored in can do. The synchronization monitoring circuit reads out the contents of these two stores and uses a logic circuit or the like to check their consistency, and when they match, it knows that synchronization is maintained and decrypts the data as described above.

Performs packet switching and demultiplexing.

If they do not match and are out of synchronization, known means are used to maintain the synchronization of the pseudorandom codes of both cryptographic devices at the same time.

Also in this reception process, the encryption fi! The input and output data bit rates of i13 can be kept exactly the same.

As is clear from the above explanation, in this embodiment, it is possible to set the data input/output speeds of the sending and receiving cryptographic devices to be the same. As a result, multiplex communication can be performed by sharing the general communication line with other non-encrypted packet data.

In the embodiment shown in Figure 1, one-way communication in which two-way communication is performed via the communication line 1101 has been explained as an example, but it is clear that communication in other directions can be carried out in exactly the same way. A) Therefore, each packet multiplexer, packet switch, encryption device, and modem each have the same functions.

Furthermore, in the embodiment shown in FIG. 1, encryption processing and related processing are given priority, but it is clear that even non-priority processing can be carried out in the same way. It can be easily implemented without compromising the

〔Effect of the invention〕

As explained above, according to the present invention, the encryption synchronization performed when the packet data transmitted and received via the bat exchange network is encrypted and transmitted and received via the encrypted communication line is monitored, and the synchronization for transmitting the synchronization monitoring signal is performed. In the supervisory signal transmission method, the encrypted packet data can be transmitted using a general communication line by providing a means for transmitting the synchronized supervisory signal as packet data via a packet switch or a packet multiplexer, and transmitting the encrypted packet data. Therefore, it is possible to realize a synchronous supervisory signal transmission system that can significantly simplify the system.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the synchronous supervisory signal transmission system of the present invention, and FIG. 2 is a block diagram showing the basic structure of the conventional synchronous supervisory signal transmission system. 1... Packet switch, 2... Encryption device, 3... Modem, 4... Modem, 5
... Encryption device, 6 ... Packet switch, 7-1 to 7-N ... Terminal equipment, 8 ...
・Packet multiplexing device, 9... Packet switch, 10... Encryption device, 11... Modem, 12... Modem, 13...・Encryption device, 14...Packet switch, 15...
Packet multiplexer, 16-1 to 16-N...
terminal equipment. \To - Broom 2 Field

Claims (1)

[Claims] A synchronization monitoring signal transmission method that transmits a synchronization monitoring signal for monitoring cryptographic synchronization in encrypted communication in which packet data is encrypted and sent/received via a packet switching network, and the synchronization monitoring signal is transmitted by a packet switch or packet multiplexer. 1. A synchronization supervisory signal transmission method comprising a synchronization supervisory signal transmission means for assembling into packet data through a converting device and transmitting the data to a transmission line.