JPS58106929A - Method and device for secret communication - Google Patents

Abstract

PURPOSE:To perform the secret communication easily, well, and surely with a low cost, by dividing an aural signal to transpose the arrangement by delay equipments different in delay time and operations of switches connected to them. CONSTITUTION:When an aural signal having a certain arrangement is inputted from an aural signal source, switches S1-S9 for rearrangement are closed simultaneously by a switching controller SW, and the aural signal is inputted to delay equipments D1-D8, which are different in delay time, syllable by syllable. After a certain delay time from the start of the input of the voice, a signal where syllables are rearranged is outputted to a signal line l2. This signal is inputted to delay equipments D'1-D'8 which are different in delay time and are similar to delay equipments used for the rearrangement of syllables, simultaneously through the signal line l2, and switches S'1-S'9 are controlled by a switching controller S'W to rearrange the signal to the original syllable arrangement.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a secret communication method and apparatus for dividing an audio signal in time, assembling an array of the divided audio signals, and viewing the gI to prevent the content of the communication from being judged by eavesdropping.

Conventional confidential communication methods have utilized analog and digital methods. Analog methods include Hibi B (8
1ngle 81cLe Band) is used to arrange the high and low frequencies of the audio frequency spectrum in reverse order, which is the so-called frequency inversion method, and an improved version of this method is the frequency division inversion method, in which the audio frequency spectrum is divided into several blocks and rearranged. There are methods etc. On the other hand, digital methods include POM (Pu1se 00 (18
Modulation) and further diffused PM (pg
・There is a so-called spread spectrum method in which the signal spectrum is spread over a wide band using a U modified code.

However, each method also has drawbacks.

In other words, the analog frequency inversion method is
It is easily demodulated and it is impossible to obtain good confidentiality.

In both digital methods, good confidentiality can be easily obtained by digitizing (numerically encoding) the analog audio signal, but this processing greatly expands the bandwidth occupied by the signal. , that is, there are drawbacks ranging from several tens of KHM to several MHz. For this reason, the analog signal band (30
0HII~3000Hg), and despite the rapid progress of digital semiconductor devices in terms of equipment configuration, it is still extremely complex and expensive69, and for specific applications (satellite communications). 2 military communications).

The present invention has been made in view of the above drawbacks, and includes #
Narrow band (300 to 3000
B11) #Confidential communication method and device that is low cost and has good and reliable confidentiality f: The purpose is to provide a long service life.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram of the principle of the method of the present invention. FIG. 1 is a diagram showing a continuous audio signal divided into temporal intervals of 1fjl. Now, each syllable has 7 sections. Le.

Assuming that the array is i, ke, ya...
As shown in Figure 1, an audio signal is created by extracting one syllable from every six sections from this audio signal. This audio signal is naturally thinned out by four syllables, so it is almost impossible to hear and understand. Similarly, the syllables of the other thinned out parts cannot be understood if the audio signal is extracted at a rate of 4. Therefore, Figure 1C
The six sections shown in the figure are taken as one block, and within this one block, the syllable arrangement is rearranged to a different arrangement from the original audio signal arrangement, resulting in I, Y, R, F, K, etc. When creating a signal, this sound also cannot be heard and understood; in order to understand this sound, the arrangement that was rearranged in the order from C to d in Figure 1 must be restored.
Therefore, the syllable combination processing proposed here can also be used for confidential communication.

Here, the time to apply one sound [IC1ltl is in Japanese,
In normal conversation, the number of syllables is 6 to 8 syllables per second, so when composing and storing 4 sections per second, the number of syllables is 0.
．． 2 seconds, OJ5 seconds for 6 sections, 0.0 seconds for 8 sections.
One paper machine degree should be appropriate, but according to experimental results, good results can be obtained with a range of 100 degrees, so the above values are only a rough guide. Naturally, if there are many sections in one block, the arrangement will have to be rearranged frequently, making decoding difficult, but if there are too many sections, the price will increase and the time required to rearrange the arrangement will become difficult. It becomes impractical due to the increase in the number of numbers, and the number of I-, -Kaku 1st place is the limit.

In order to simplify the explanation, we will assume that one syllable enters the 1st section, and there are cases where the 1 syllable of 9 enters the 2nd section mK1 running, but there is no significant difference in terms of perception. A specific method and apparatus for performing recombination processing according to the invention will be described.

FIG. 2 is an illustrative connection diagram of the transmitting side in the method and apparatus of the present invention. In FIG. 2, ~D.

is divided into nine analog delay devices (using BBD devices and CaD devices), and each delay device D1 to D
, the delay times are different. The delay device DS has a delay time of T11, which is the same as the delay time of 114, and the delay device proverb is 2Td time, which is twice the delay device, and the delay device is three times 3T (in 1 hour). Similarly, it gets longer, and the delay time increases.
In this case, the length is 8 times that of J3Td3T. These i! ! #, Rearrange the syllables by delaying the syllables of each part as appropriate depending on the instrument.

Now, from the audio signal source, "7", "ru", "i" as shown in Figure 1.
Do you signal “r” and “ya”? Enter in IMlx.

Switch for rearrangement at the same time 8. Close switch B using switch control device 8W and input "7" to delay device D, then close switch B and input "7" to delay device D. Then, after KTd seconds have elapsed, switch K to set the delay time, and then close the switch S to set the delay time.
Close switch Bm and input "Y" to the delay device D4, close switch B and input "R" to the delay device D4, and input the following voice in the same way. Figure 4 shows FIG. 3 is an explanatory diagram of operations for temporal division and rearrangement of audio signals; In this way, if 1iF# is input to the delay device through the switch, 4!1 seconds after the start of audio input, 1 is input at a relatively early stage in the audio signal, and the delay time is small. ``A'' is output from the delay device Dl, and then ``Ya'' is output from the delay device, followed by ``RU'', ``FUHA'', ``KEHE'', and ``power'' is output as shown in Figure 1C... . . . is rearranged into the syllable yarufkeka . . . as shown in Figure 1 d [. 1 according to the 6-section syllable of makuji
Blocks may also be rearranged in the same way, but
Rearranging blocks differently from the previous block, such as this, has an even better effect in increasing the degree of secrecy.

Next, a method for decoding the recombined signal sent from the transmitting side on the receiving side will be described. FIG. 3 is an explanatory connection diagram of the receiving side (decoding device). D′ 甑〜p/, are delays lID1〜D used in syllable recombination.

It is exactly the same as , and the delay time is also the same.

The assembly signal shown in FIG. 1d is connected to the signal line t/.

It is input to each delay device D11 to DI at the same time.

FIG. 5 is an explanatory diagram of the operation for recombining the recombined signal into the original audio signal. The switching control device 8'w controls the switches B/, ~B', to output the recombination signals "I", "Y", "R", "F", "Ke", "Power", etc. in FIG. 1d.・・・・・・
4Td seconds after applying the signal, switch 8' is turned on/off, selects the delay device p/, and extracts "F", and the 5Td signal is applied.
(After 1 second, switch 8'4 is turned on and the delay device p/,
Select and extract "ru", 5T (after 1 second switch Bz
Turn on , select delay device D' and extract "A", 7
After Td seconds switch 8/.

Turn on, select delay device D/l, extract "ke", and select gT.
After d seconds, turn on the switch B/a, select the delay device D/, and press "Y", and press 9T (after 1 second, turn on the switch Bl, select the delay device D/, and press "R"). If you extract and perform operations like this from now on, the original syllable sequence "]""
The words are rearranged into ``ru'', ``i'', ``ke'', ``ya'', ``power'', and can be read. In addition, when decoding, it is important to discuss the arrangement order with the transmitting side in advance, and to
A synchronization signal for aligning the timing of the array for each 6th section 0ii (1 block) (same signal as the 9th time when rearranging processing is performed)
is necessary.

This synchronization signal is transmitted from the transmitting side to the receiving side in the same way as the recombination signal.
Alternatively, it must be transmitted on another line, but that method is not the gist of the present invention, and many methods are currently in practical use (selective calling method, linconvex demodulation, etc.), so here, 4! Don't touch.

In the above description, the recombination of syllables and the rearrangement back to the original syllable) are performed using delays aD1 to D.

p/1~D/Hata shows the delay time T (9 pieces using multiple delay devices of 1 (in this case, too, it can be divided into many sections and can be considered as a round device), but it is difficult to fabricate an actual delay device. When the delay time is the same as the F1 maximum delay time (here, g
7a seconds) may be used, and a tap may be provided for each Ta time so that a signal can be taken out every time there is a delay of .tau.d. In this case, the configuration can be made even simpler.

As is clear from the above explanation, according to the present invention, a good degree of confidentiality can be obtained by increasing the number of syllable rearrangements to a certain extent, and since signal processing is performed within the audio signal band, When the present invention is used in a telephone communication device, etc., the communication device needs only to be installed as a jlLK addition device with almost no modification, and it is extremely easy to implement and has many industrial advantages.

[Brief explanation of drawings]

Figures 1 to d are diagrams for explaining the principle of the method of the present invention, Figure 2 is a connection diagram for explaining the transmitting side in the method and apparatus of the present invention, Figure 3 is a connection diagram for explaining the receiving side, and Figure 4 is a diagram for explaining the connection diagram of the receiving side. FIG. 5 is an explanatory diagram of the operation of temporally dividing the audio signal and rearranging the arrangement. FIG. 5 is an explanatory diagram of the operation for rearranging the recombined signal into the original audio signal. Dl~I)stI"t~D7. Delay device, 81~B0.stl, 5l11110.180.
Switch, Sv, 8'v......Switching control device, stone I Lm f t'l f t'!・・・・・・
···Signal line. Jun 2nd country book q map

Claims (3)

[Claims] (1) Using analog delay devices that are divided into multiple sections and having different delay times, the audio signal is divided in time by operating a switch connected to each delay device, and the arrangement of the divided audio signals is A secret communication method that can be assembled. (2) By limiting the recombination speed to several times per second or to the degree of rotation, and preventing an increase in the audio signal band due to rewriting, it can be used in ordinary acoustic communication equipment. IIS Section 1 Go Confidential Communication Method (3) An analog delay device that is divided into multiple sections and has a uniform delay time, and each delay device is connected in series with nine switches, and both ends of each series circuit are connected to a common signal line. Confidential communication device.