JPS617743A - Privacy communication device - Google Patents

Abstract

PURPOSE:To make privacy communication, in which the tone quality is not deteriorated, with a semi-duplex transmitting device equipped with an ciphering circuit and privacy generating circuit, by performing the communication by producing changes in privacy variables and privacy constants at the pause of conversations. CONSTITUTION:Voice signals inputted from a terminal 101 is subjected to privacy treatment at a privacy transmitting circuit 102 and then signal-multiplexed 103 and transmitted 104. When the transmission/reception controlling signals of an input terminal 105 is inputted through a push-button, output of a random number generating circuit 106 is fetched by a latch circuit 107 and, at the same time, a transmitter 104 is set to a transmitting state. Moreover, output of the circuit 107 is inputted in the device 102 and causes the device 102 to generate a privacy variable and constant. The output is also multiplexed 103 after it is ciphered by means of a ciphering circuit 109. At the receiving side, on the other hand, the signal multiplexed at the transmitting side is separated from received signals by means of a signal separating circuit 203 and the privacy sound signal out of the separated signals is inputted in a privacy receiver 202 where the privacy talk is returned to the original state. The ciphered privacy variable and constant are decoded by a cipher decoding circuit 208.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a confidential communication device for controlling the confidentiality of conversations, and in particular,
The present invention relates to a confidential communication device used in a half-duplex communication device.

(Prior Art and its Problems) Among the characteristics of a confidential communication device, the intensity of confidential communication and the sound quality are important issues.The intensity of 0 confidential communication can be increased by temporally changing the confidential communication parameter. However, in conventional confidential communication devices, since this parameter is changed periodically, switching noise is generated every time the parameter changes, resulting in a problem that the sound quality deteriorates.

(Object of the invention) The object of the invention is that even if the secret conversion variable is changed,
An object of the present invention is to provide a confidential communication device without deterioration in sound quality (Arrangement of the Invention) According to the present invention, there is provided a confidential communication device that performs confidential communication on an input signal in cow duplex communication, which uses a random number generation circuit described later. A confidential conversation conversion circuit that converts an input signal into a confidential signal by changing a confidential conversation conversion parameter according to a confidential conversation parameter signal that is supplied, a communication direction switching signal generation circuit for switching the communication direction, and switching from the switching signal generation circuit. a random number generation circuit that supplies a numerical value generated each time a signal is supplied to the confidential message transmission circuit as a confidential parameter signal; an encryption circuit that encrypts the confidential parameter signal; means for completely separating the secret signal and the encrypted secret parameter signal from the signal; decryption means for returning the encrypted secret parameter signal supplied from the means to the secret parameter; There is obtained a confidential communication device characterized in that it is comprised of a receiving side that includes at least a confidential communication inverse conversion circuit that inversely converts the confidential communication signal into confidential communication in accordance with a confidential communication parameter signal.

(Embodiment) The present invention focuses on the fact that conversations take place alternately in half-duplex communication, and prevents deterioration of sound quality by always changing the confidential conversation parameter at the break in the conversation.

FIG. 1 and FIG. 2 show the first lines of the confidential communication device of the present invention, respectively.
FIG. 2 is a block diagram of a transmitting device and a receiving device in an embodiment of the present invention. The audio signal that is input to the input terminal 101 is encrypted by the confidential message transmitting circuit 102, and then sent to the signal multiplexing circuit 1 to receive an encrypted confidential message parameter signal, which will be described later.
After being input to 03 and multiplexed, it is transmitted by a transmitter 104.

The confidential message transmitting device 102 may be of any type as long as its parameters can be changed during the confidential message operation.For example, it may be a so-called band division exchange method in which the audio band is divided into several bands and exchanged. At this time,
There are many ways to swap bands, and this is a secret parameter. The secret parameter is the random number generation circuit 1
It is determined by a random number generated by 06. The specific method of generating secret parameters using random numbers is well known and is not important to the operation of the present invention, so a detailed explanation will be omitted here.

What is important is how to switch parameters at breaks in conversation.

A transmission/reception switching control signal is input to the input terminal 105 . This transmission/reception control signal is normally generated by a push button attached to the microphone.

When the push button is pressed to carry out the transmission, the random number generation circuit 10
At the same time that the output of 6 is received by the latch circuit 107, the transmitter 104 is placed in a transmitting state. Latch circuit 107
The output is input to the secret message transmitting device 102 to generate a secret message parameter, and at the same time, it is input to the encryption circuit 109 and encrypted, and then input to the multiplexing circuit 103. The encryption circuit 109 may be of any type as long as the input signal cannot be easily identified by the output signal, and may be constructed of, for example, a well-known nonlinear feedback shift register. The signal multiplexing circuit may have any configuration as long as the multiplexed signals can be separated on the receiving side, for example,
Frequency multiplexing may be considered in which an encrypted secret parameter signal is inserted into the lower band (0 to 300 Hz) of the audio signal spectrum 7y. In this case, on the receiving side, the two signals will be separated by a filter.
The multiplexed signal is input to the output signal separation circuit 203 and is separated from the multiplexed signal performed on the transmitting side. Of the separated signals, the confidential voice signal is input to the confidential voice receiver 202 to restore the confidential voice.0 Among the separated signals, the encrypted confidential voice parameter signal is decoded by the decryption circuit 208, and then converted into the confidential voice parameter. The 0 encryption/decryption circuit 208 stored in the signal reception circuit 209 operates in pair with the encryption circuit 109, and the specific configuration differs depending on the encryption method used. , in order to restore the secret message, it is necessary to know the secret message parameters, and for that purpose, the encryption must be broken.
1 is a diagram showing a block diagram of a transmitting device and a receiving device in the embodiments.0 In these embodiments, a latch circuit 308 is newly added to the transmitting device, and a latch circuit 407 is newly added to the receiving device, with respect to the first embodiment. The other parts operate in the same way.Therefore, only the parts that are different from the first embodiment will be explained here with emphasis. When the pushbutton is pressed to perform transmission, a transmission/reception switching control signal is input to the input terminal 305, and the ratte circuits 307 and 3
At the same time as 09 is activated, a 0 audio signal is input from the input terminal 301 to put the transmitter 304 into the ffi transmission state.
After passing through the confidential message transmission circuit 302 and the multiplexing circuit 303e, it is transmitted from the transmitter 304. The output of the random number generation circuit 306 is first input to the latch circuit 307, and then becomes the input to the latch circuit 308, and at the same time, the output is input to the encryption circuit 3.
09, and is combined with the private voice signal in the signal multiplexing circuit 303 and then transmitted.

Since the latch circuit 308 lattes the output of the latch circuit 307, its output signal is a signal that is temporally earlier than the output signal of the latch circuit 307 by l latch steps. Therefore, the secret parameter of the secret message transmission circuit 302 is earlier than the output of the secret parameter encryption circuit 309 by one rate step. As a result, the transmitting device transmits the secret parameter before the time when it is actually used.

The signal received by receiver 404 is transmitted to signal separation circuit 40
3, the signal is separated into a confidential audio signal and an encrypted confidential parameter signal. The confidential speech signal is decrypted by the confidential speech receiving circuit 402, and a transmission audio signal is obtained at the output terminal 401. The encrypted secret parameter signal is decrypted by the encryption/decryption circuit 408 and then stored in the secret parameter signal receiving circuit 409 . The output of the confidential parameter signal receiving circuit 407 is
The transmission/reception transfer control signal inputted to the input terminal 405 is used as a latch signal and is input into the latch circuit 407, which outputs the confidential message parameter to the confidential message receiving circuit. The received confidential parameter signal may be processed to include operations to reduce reception errors. In this embodiment, since the confidential parameter is transmitted in advance, the reliability of confidential parameter transmission can be increased by transmitting the confidential parameter many times in this way. (Effects of the Invention) In the present invention, Since the parameter changes are made at breaks in the conversation, there is an advantage that the sound quality does not deteriorate due to parameter changes.

Furthermore, in the present invention, since the output of the random number generation circuit can be received at any time, the clock signal of the random number generation circuit can be made irrelevant to signal transmission and reception, and the configuration of the random number generation circuit is easy. The effect of becoming

[Brief explanation of the drawing]

1 and 2 are block diagrams of a transmitter and a receiver, respectively, in a first embodiment of the present invention, and FIGS. 3 and 4 are block diagrams, respectively, of a transmitter and a receiver in a second embodiment of the present invention. and a block diagram of a receiving device are shown in these figures. 101, 301 are audio signal input terminals, 102.302
is a secret transmission circuit, 103.303 is a signal multiplexing circuit, 1
04, 304 is a transmitter, 105. 305. 40
5 is a transmission/reception transfer control signal input terminal, 106.306
is a random number generation circuit, 107. 307. 308.407
is a latch circuit, 109, 309 is an encryption circuit, 201
．． 401 is an audio signal output terminal, 202. 402 is a secret reception circuit, 203.403 is a signal separation circuit, 204.
404 is a receiver, 208° 408 is an encryption/decryption circuit, 20
9.409 is a confidential parameter receiving circuit.

Claims (1)

[Claims] A confidential communication device that performs confidential communication on an input signal in half-duplex communication, the confidential conversion circuit converting the input signal into a confidential signal by changing a confidential conversion parameter according to a confidential parameter signal supplied from a random number generation circuit described later. a communication direction switching signal generation circuit for switching the communication direction; and a random number generation circuit that supplies a numerical value generated each time a switching signal is supplied from the switching signal generation circuit to the confidential communication transmission circuit as a confidential communication parameter signal. , a transmission side including at least an encryption circuit for encrypting the secret parameter signal, and means for multiplexing and transmitting the output of the secret conversion circuit and the output of the encryption circuit; means for separating the signal from the encrypted confidential parameter signal; decryption means for returning the encrypted confidential parameter signal supplied by the means to the confidential parameter; and a confidential parameter signal supplied by the decryption means. 1. A confidential communication device comprising: a receiving side that includes at least a confidential communication inverse conversion circuit that inversely converts the confidential communication signal in accordance with the confidential communication.