JPH0294835A - Scpc communication equipment - Google Patents

Abstract

PURPOSE:To improve the secrecy of a communication line by providing a function sending a code data of a scramble pattern being a privacy call key at the outside of a transmission band and stopping the privacy call processing scramble only for a setting processing time interval of a new code data. CONSTITUTION:In the case of applying the privacy call processing, a scramble section 3 applies the privacy call processing to a transmission signal based on a scramble pattern according to a code data generated in a control section 4 at random. The privacy call scramble pattern is varied during the signal transmission in the privacy call processing. In this case, as soon as a new code data of the scramble pattern is outputted from the control section 4, a changeover section 2 is switched to a transmission line where no privacy call processing is applied. In the case of recognizing the revision of a code data of the scramble pattern by a modulation data outputted from a data demodulation section 9, a control section 10 of the reception system throws a changeover section 12 to the position of a transmission line where no privacy call processing is applied and provides a time in which no privacy call processing in applied to the transmission signal.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a 5cpc communication device that transmits voice and data using a telephone over a satellite communication line, and in particular, to a 5cpc communication device that implements confidential processing. do.

[Prior Art] Generally, in satellite communication, 5CPC (Single Channel) transmits multiple narrowband carriers.
Per carrier) communication devices are widely used for transmitting voice or data using telephones.

Here, in order to connect the satellite line, the transmitting side modulator (m
It is necessary that the carrier frequencies of the modulator (ad) and the demodulator (dem) on the receiving side match one of many waves, and the modulator and demodulator are usually connected by a satellite link with l = 1. .

However, in this case, if the carrier frequency of the demodulator is set to the carrier frequency of the modulator to which reception is desired, the transmission signal can be received on a line other than the originally connected line. For this reason, it is desirable to perform concealment processing (scrambling) on transmission signals that require confidentiality.

However, in the conventional 5cpc communication device, such concealment processing was not performed.

[Problems to be Solved] The conventional 5cpc communication device described above did not perform concealment processing on the transmitted information, so if the carrier frequency of the demodulator (DEM) could be set to the frequency that you want to intercept,
The problem was that wiretapping could be easily done.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a 5-cpc communication device that can perform secrecy processing on transmission signals that require confidentiality.

[Means for Solving the Problems] In order to achieve the above object, the 5cpc communication device of the present invention includes a cipher processing means that can select whether or not to perform ciphering processing on the transmitting side, and a cipher processing means for this ciphering processing means. a first control means for controlling whether or not to perform the encryption and determining scramble pattern data in the concealment processing; and a data modulation means for modulating the scramble pattern data determined by the first control means into a narrow band. , a modulation means for modulating the output of the data modulation means into a transmission signal, and a demodulation means for demodulating the received signal, and a modulation means for modulating the output of the demodulation means into the low band as described above. data demodulation means for extracting and demodulating scrambled pattern data; reproduction processing means for selecting whether or not to perform reproduction processing on the output of the demodulation means; and whether to perform reproduction processing for the reproduction processing means. and second control means for controlling whether or not the scramble pattern data is input from the data demodulation means and for outputting the scramble pattern data input from the data demodulation means to the reproduction processing means.

The first and second control means control the concealment processing means and reproduction processing means not to perform concealment and reproduction processing during the scramble pattern change processing period.

In other words, using integrated circuits for secrecy processing that have been commercialized as a result of advances in device technology in recent years, the transmission signal is subjected to secrecy processing, and the n which is the key to the secrecy is used.
Bit code data is subjected to narrow band modulation and transmitted to the receiving side at a frequency outside the transmission band (300H to 3.4kHz). Based on this code, an integrated circuit prepared on the receiving side reproduces the transmitted signal. Further, at this time, the confidentiality of the communication line is improved by not performing the confidentiality process during the scramble pattern change processing period.

[Example] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a block diagram of a 5cpc communication device according to an embodiment of the present invention.

In the figure, 1 is a transmission signal input terminal, 2 is a switch that switches the transmission path, 3 is a scrambler that performs cipher processing, 4 is a control unit that controls the switch 2 and the scrambler 3, and 5 is a controller that controls scramble pattern data. A data modulation section 6 modulates the transmission signal into a narrow band, and a modulation section 6 modulates the transmission signal and the modulated scramble pattern data to generate a transmission signal.
MOD) section.

Further, 7 is a demodulation (DEM) unit that demodulates the received signal, 8 is a band pass filter that selects a narrow band, and 9
1 is a data demodulation unit that performs IM modulation of scramble pattern data modulated into a narrow band; IO is a control unit; 11 is a descrambling unit whose reproduction of data is controlled by the control unit 10; 12 is a switching unit that switches the output signal; and 13 is a This is a transmission signal output terminal.

In the above configuration, the transmission signal is input from the input terminal l. At this time, the control signal from the control section 4 controls the switching of the switching section 2 depending on whether or not the concealment process is performed.

In other words, when performing concealment processing, the scrambler 3
The connection is made so that the signal is input to the modulation (MOD) section 6, and when the concealment processing is not performed, the connection is made so that the signal is input to the modulation (MOD) section 6. In addition, when ciphering processing is performed, the scrambling unit 3 performs ciphering processing on the transmission signal based on a scrambling pattern according to parallel code data consisting of n bits randomly generated in the control unit 4. This signal is input to the modulation section 6. and,
The output of the modulator 6 is demodulated (
The demodulated wave is input to the descrambling section 11 and the switching section 12. Then, switching of the switching unit 12 is controlled by a control signal from the control unit 11 depending on whether or not confidentiality processing is performed.

That is, if the transmission signal has been subjected to encryption processing, the output of the descrambler 11 is sent to the transmission signal output terminal 13, and if the encryption processing is not carried out, the output of the demodulator 7 is sent to the transmission signal output terminal 13.
Output to .

By the way, if the transmitted signal is concealed,
In order to reproduce an accurate transmission signal, it is necessary to transmit information on the scramble pattern that has been encrypted by the scrambler 3 of the transmitter to the descrambler 11 of the receiver. At this time, the secrecy processing of the scrambling section 3 and descrambling section 11 is configured by an integrated circuit, and by inputting n-bit parallel data to the code data input port of the scrambling pattern, 2'1 scrambling patterns are generated. You can choose.

As described above, the code data of this scramble pattern is generated by the transmission system control unit 4 using random numbers. Then, it is sent to the scrambler 3 as parallel data, and at the same time the scramble pattern for the transmission system is determined, it is also sent to the data modulator 5. Thereby, the data modulation unit 5 performs narrow band modulation at the center frequency fθ, and transmits it externally (300 Hz to 3.4 kHz) via the satellite communication line.

On the other hand, the data modulated wave of center frequency f8 demodulated by the demodulator 7 is selected by the bandpass filter (center frequency 18) 8, further demodulated into n-bit data by the data demodulator 9, and then is input to. Therefore, the control unit 10 sends the scramble pattern for the encryption process determined on the transmitting side to the descrambler 11 as 11-bit parallel data, and the descrambler 11 performs the encryption process based on this data. The original transmission signal is reproduced from the transmitted signal.

In addition, in this concealment process, the code data of the scramble pattern can be transmitted regardless of the presence or absence of the transmission signal, so
It is also possible to change the secret scrambling pattern during signal transmission.

At this time, at the same time as the new code data of the scramble pattern is output from the control section 4, the switching section 2 switches to the transmission path on the side where the transmission signal is not subjected to the ciphering process.

On the other hand, when the control unit 10 of the reception system recognizes that the code data of the scramble pattern has been changed by the modulated data output from the data demodulation unit 9, the switching unit 12 performs a ciphering process on the transmission signal, similar to the transmission system. The transmission line is switched to the side where the transmission line is not being used. Therefore, if this switching operation is used to provide a time period in which the transmission signal is not encrypted until the scramble pattern change is completely completed, the scramble pattern can be changed arbitrarily, and the communication line It is also possible to improve the confidentiality of the information.

In this way, in this embodiment, the transmission path of the input signal is switched by the control signal from the first control section.
a switching section, a cipher processing section that performs cipher processing on the input signal, a first control section that controls the cipher processing section and the switching section, a data modulation/demodulation section that performs narrow band modulation/demodulation processing on digital data, and a data modulation/demodulation section that performs narrow band modulation/demodulation processing on digital data. A bandpass filter controls the band of the modulated wave output from the section, and a second switch is used to switch between the transmission signal path that reproduces the encrypted signal and the signal path that has been transmitted without enciphering.
and a second switching section that performs the switching based on a control signal from the control section.

Then, during the scrambling pattern change processing period, the route is switched to a route in which no concealment processing is performed.

[Effects of the Invention] As explained above, the present invention has a function of transmitting the code data of the scramble pattern that is the key to secrecy outside the transmission band, and stopping the secrecy process for a time interval for setting new code data. This allows the scrambling pattern to be changed freely even during signal transmission, which improves the confidentiality of the communication line5.
This has the effect of providing a CPC communication device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a 5cpc communication device according to an embodiment of the present invention. 2.12: Switcher 3 Niscrample section 4.10: Control section 5: Data modulation section 6: Modulation section 7: Demodulation section 8: Bandpass filter 9: Data demodulation section 11: Descrambling section

Claims (1)

[Claims] On the transmitting side, there is provided an encryption processing means that can select whether or not to perform encryption processing, and a controller that controls whether or not to perform encryption processing for this encryption processing means and determines scramble pattern data in the encryption processing. 1 control means, data modulation means for modulating the scramble pattern data determined by the first control means into a narrow band, and modulation means for modulating the outputs of the concealment processing means and data modulation means into a transmission signal. On the receiving side, a demodulation means demodulates the received signal, a data demodulation means extracts and demodulates the scramble pattern data modulated into the narrow band from the output of the demodulation means, and a reproduction process is performed on the output of the demodulation means. a reproduction processing means that can select whether or not to perform the reproduction processing; and a reproduction processing means that controls whether or not to perform the reproduction processing on the reproduction processing means, and transmits scramble pattern data input from the data demodulation means to the reproduction processing means. and a second control means for outputting an SC.
In the PC communication device, the first and second control means control the concealment processing means and the reproduction processing means so that the concealment and reproduction processing are not performed during the scramble pattern change processing period. SCPC communication equipment.