JP2979057B2 - Wireless confidential system - Google Patents

Abstract

PURPOSE:To realize the privacy call system of a radio telephone set in which communication is implemented with safety by selecting and setting one privacy call pattern among plural privacy call patterns set optionally simultaneously and outputting a revision command of the privacy call pattern to a radio equipment making communication between concerned parties one after another on the way of communication. CONSTITUTION:When communication is started, a privacy call pattern 15 outputs a privacy call pattern revision command sequentially for a prescribed period or a random period and a privacy call pattern selection section 16 receives a time series code {xn} from a random series code generating section 12 of its own equipment for each occasion of a revision command, selects one privacy call pattern from a privacy call pattern storage section 10 and sets the pattern to a privacy call pattern setting section 3. The privacy call patterns of 3, 7, 1, 6... are set at random in response to the {xn}. Since the privacy call patterns of 7,5,4... are selected by a code in succession to the time series code {xn}, even when the preceding communication is decoded, the privacy call pattern of the succeeding communication cannot be estimated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to a confidential communication system of a wireless telephone such as a cordless telephone and an confidential communication LSI.

(Prior Art) In recent years, the spread of cordless telephones has been remarkable, and the wiretapping problem has been greatly highlighted.

Here, the wireless telephone is premised on the concept that a large number of people share a limited radio wave resource, so that it must be a system that allows so-called "reception" easily.

Wireless telephones have become increasingly popular for their personal sensation over the last few years of cordless Lesphones, but since they do not think that third parties are listening, In response, it's easy to escalate to a "buzzy" story. However, this cordless telephone is "broadcasting" on radio waves over a range of several hundred meters in radius. Also, when a PIN or bank account number is entered using the push button, the PB signal is "broadcast" in a form that is easily understood.

Here, the eavesdropping side justifies eavesdropping, saying that it is not "eavesdropping" because it is "broadcast" and enjoys "receiving" because it is "broadcasting", and studies various eavesdropping methods. Also tend to increase.

Therefore, no matter how good a confidential system is developed, as long as it is mass-produced for consumer use and used for mass consumption, the confidential system can be used by individual users. The dilemma arises that it is impossible with a unique entity. In other words, a confidential system is a system that is unique to each user in order to be useful, and that other systems cannot manage the system. However, in a narrowband multi-access wireless telephone system,
No matter how good a confidential system is installed, the above two conditions are easily violated because others can easily obtain the same system and easily access any communication channel. It will be. Therefore, the confidentiality function introduced into a commercial wireless telephone system is only expected to impair the role of linking the product line.

As an example of a commercial confidential system, for example, there is a problem with sound quality, but "LS8931 confidential communication LS" of Sanyo Electric Co., Ltd.
Some use "I".

This is because in a cordless telephone, a confidential communication LSI is provided in the parent device and the child device, and 128 types of confidential patterns are obtained by combining a transmission pattern of 32 kinds of synchronization signals and a time pattern of four kinds of voice frequency conversion ratios. One pattern is arbitrarily set as a secret key using a 7-bit terminal, and a call is made according to the secret pattern set between the master unit and the slave unit. In this case, the original sound generated on the master unit or the slave unit side is transmitted to the slave unit or the master unit as a confidential speech sound, and is heard as the restored sound by the slave unit or the master unit.

In the confidential communication system of the wireless telephone using the confidential communication LSI, a call is made in a confidential pattern selected and set from 128 types, so that the eavesdropping side cannot perform eavesdropping unless the same pattern is set.

However, in the confidential communication system using the confidential communication LSI as described above, the method was such that one pattern was selected and set from patterns limited to the master unit and the slave unit. When a product is purchased and the setting pattern is matched, there is a problem that wiretapping becomes possible.

In other words, if a telephone using the same manufacturer's secret communication LSI is installed and the same secret pattern happens to be set by two cordless telephones, the conversation of one telephone will be replaced by the telephone of the other. Will be able to observe. Further, if the telephone is slightly modified to allow an arbitrary privacy pattern to be freely set, there remains a problem that a phone using the same privacy communication LSI can be easily eavesdropped.

Even if a confidential system is constituted only by hardware in this way, if the confidential system is mass-produced and put on the market in large quantities, there is a problem that the utility as the confidential system is diminished.

(Problems to be solved by the invention) No matter how excellent a secret system is invented and developed, its utility as a secret system is weak as long as it is mass-produced for consumer use and consumed in the market. There is a fundamental dilemma of getting lost. As long as wireless systems are copied and marketed in large quantities, and of course, as long as they are readily available and easy to operate, there is a problem that the confidentiality function is not possible in a strict sense.

The present invention describes this dilemma as a stochastic process (Stochastic Pro
cess), and while using the same or similar confidential communication LSI as before,
It is an object of the present invention to provide a confidential communication system of a wireless telephone that can be safely communicated with little possibility of wiretapping even if it is mass-produced.

[Constitution of the Invention] (Means for Solving the Problems) A radio device for making a call between parties selects and establishes one confidential pattern simultaneously from a plurality of arbitrarily set confidential patterns, and In a wireless telephone confidential system in which the original voice is converted into a confidential voice on the side and received as a radio signal, and the radio signal received on the receiver side is restored, a confidential memory storing a plurality of confidential patterns in each unit. A pattern storage unit, a random sequence code generation unit for sequentially generating a random sequence code determined according to a certain rule, a secret pattern change instruction unit for sequentially outputting a secret pattern change command during a call, When a change command is output from the pattern change instructing unit, a plurality of secrets stored in the secret talk pattern storage unit are used using the random code generated from the random sequence code generating unit. A secret story pattern selection setting section for selecting and setting one secret story turn from the patterns; a secret story for converting an original voice into a secret speech using the secret story pattern selected and set by the secret story pattern selection setting section and outputting it as a wireless signal A voice conversion unit; and a voice restoration unit for restoring a wireless signal input using the secret talk pattern and outputting the restored wireless signal as a restored speech.

In addition, one confidential pattern is simultaneously selected and set from a plurality of arbitrarily set confidential patterns in a wireless device that performs a call between the parties, and the transmitter converts the original voice into a confidential voice. In a confidential communication LSI used for transmitting a radio signal and restoring a radio signal received on the receiver side, a confidential pattern storage unit provided in each unit and storing a plurality of confidential patterns, A random sequence code generation unit for sequentially generating a random sequence code determined in accordance with the following: a secret pattern change instruction unit for sequentially outputting a secret pattern change instruction during a call; and a change command output from the secret pattern change instruction unit. When one of the secret patterns is stored in the secret pattern storage unit using the random code generated by the random sequence code generation unit, And a secret story pattern selection setting unit for selecting and setting a pattern.
The original voice is converted to a secret voice using the secret pattern selected and set by the secret pattern selection setting unit, and the input wireless signal is restored using the same secret pattern and output as a restored voice. I do.

(Action) To further mention, any complete secret system,
Several variations are allowed, such as restoring and restoring the source sound by selecting one secret sound selected from a plurality of secret sounds. If additional software for determining which secret story pattern is used is introduced, it can be considered as an operating system (OS) that manages application programs from pattern (1) to pattern (n). This will be referred to as “secret story OS”. While application programs will be given to all users in common, personalized OS will be individualized by some means for each user, and a method of individualization that will not be able to manage once refined individuality will be searched. . If this were possible, it would have provided a unique confidential feature for each user.

The only possible method for individualization is the introduction of stochastic processes. If the performance of the esoteric OS was a random process, it would be practically impossible to track the performance of the esoteric feature under this control.

Therefore, the following random process is introduced into the secret story OS.

After entering the call state, change the confidential pattern one after another; leave a random process to decide which pattern to change or when to change it; other radio stations decide which pattern to change to next Do not put any information or signals that can be inferred on the radio at the time of the call; and the requirement of the paragraph is that a pair of radio stations make "random movements", and that "random" It is the same as always coincidentally. Only a fractal approach makes this possible. It "determines" this random process, the "random process", by a function of a discrete dynamical system.

The discrete dynamical system function is represented by the following equation: x _n = f _p (x _n-1 ) x _n ; random time series (digital) p; parameter, arbitrary value during continuous interval [0,1] parameter p , One characteristic random time series is generated (for details, see the reference book, for example, July 21, 1986).
"Chaos and Fractals 29-34" issued by Kodansha
Page, “Approach to make a random sequence”).

The random process at the end of the call is involved in the start of the random process at the start of the next call.

The parameter p characterizing the discrete dynamical system is determined at random by some easy means after the user purchases the system, and is initially set to the base side and the mobile station side simultaneously or at the time of connection (at the time of access by the control channel, ) Each time it is set in relation to the term.

 The above is the theoretical configuration of the secret story OS.

When this is introduced, it is practically impossible to intentionally track the performance of confidential stories. Note that it is possible, at one moment only, that the two random processes coincide, but that this is by no means controlled by an eavesdropper.

Therefore, in the confidential communication system of the wireless telephone according to the present invention, in the configuration as described above, both of the wireless devices (including the repeater), for example, the above-mentioned respective functional members are provided in the parent device and the child device of the cordless telephone. A confidential pattern that changes every moment can be set simultaneously, and confidential communication can be performed between the two devices.

At this time, since the confidential pattern set simultaneously for both devices is a confidential pattern randomly set from a plurality of confidential patterns using a random sequence code, even if the confidential radio signal is decoded, It is impossible to estimate a secret story pattern, and wiretapping can be reliably prevented.

Even if the same parameter is set for the same type of telephone, if the call start time is different, there is almost no possibility that the same secret pattern will be set at the same time.

As described above, the code of the random sequence determined under a certain rule is calculated from the random time series {X _n } by the function of the discrete dynamical system X _n = f _p (X _n-1 ) which is made unique by the parameter setting. Obtainable.

In addition, if the change synchronization of the confidential pattern determined sequentially in this manner is selected from a plurality of periods using the same random sequence code, both the confidential pattern and the change period can be random, and the scrambled confidential voice can be used. Eavesdropping can be more reliably prevented.

The random time series code {Xn} is generated by a fixed amount,
The secret story pattern may be set at a stroke so as to be sequentially selected, or may be generated one by one for each change command.

(Embodiment) FIG. 1 is a block diagram showing a confidential communication system of a wireless telephone according to an embodiment of the present invention, and FIG. 2 is a time chart showing its operation.

As shown in the figure, a transmitter / receiver 1 includes an original voice input unit 2 for inputting an original voice, and a secret voice conversion unit 4 for converting the original voice into a secret voice using the secret pattern set in the secret pattern setting unit 3. And a wireless signal output unit 6 for outputting a secret voice from the antenna 5 as a wireless signal.

The antenna 5 includes a radio signal input unit 7 for inputting a radio signal input to the antenna 5, and a voice for restoring this signal using a secret pattern currently set in the secret pattern selection setting unit 3. The apparatus includes a restoration unit 8 and a restored audio output unit 9 that outputs the restored audio.

Further, in the present embodiment, a secret pattern storage unit 10 for storing a plurality of secret patterns, a random sequence code generator 12 connected to a parameter setting unit 11, a secret pattern connected to a clock 13 and a synchronization adjuster 14, Using the change instructing unit 15 and a code generated by the random sequence code generating unit 12 based on the instruction timing of the change instructing unit 15, selecting one secret pattern from the secret pattern storage unit 10 and setting the secret pattern selection A secret story pattern selecting section 16 to be set in the section 3; The members 11 to 16 together constitute a secret OS.

The secret story pattern storage unit 10 is for the secret story communication shown in the conventional example.
The time pattern of the frequency conversion ratio may be the same as the secret story pattern set in the LSI, or a combination of these patterns may be used.

The random sequence code generator 12 has a function x _n = f _p (x _n−1 ) (1) of a discrete dynamical system represented by the following equation, sets a parameter P in the function form f, and sets an initial value X ₀ Is given, the random time-series code {xn} is sequentially output in accordance with the instruction of the secret pattern change instruction unit 15.

For example, when “3” is given as an initial value and a certain parameter P is set, the above equation becomes {3,7,1,6,2,7,5 ...}
Assuming that a time-series code is generated, for example, for seven types of confidential patterns, the third, then the seventh, and then 1,
The 6,2, ... th secret story pattern will be selected.

These time series codes {x _n } are random numbers,
Since the setting is performed according to a certain rule, the same code is set simultaneously in both the transmitting and receiving units.

Further, these time-series codes {x _n } are determined by the above equation f, parameters, and initial value x ₀ , and the code to be set next is determined by the history up to the present time according to the total talk time. Therefore, it is impossible to predict the same confidential pattern between telephones having different backgrounds.

The synchronization adjustment unit 14 outputs an initial confidential pattern setting command to the confidential pattern change instruction unit 15 in accordance with the call start time, or performs correction processing of the clock 13 between the two stations for an excessively long call. is there.

In the confidential communication system having the above configuration, when a parameter is set from the parameter setting unit 11 when the telephone is installed, the parameter P is set in the function form f of the random sequence code generation unit 12. Even if the initial value x ₀ is set in the individual time series code {xn}, or may be set in advance.

Therefore, when a call is started, the confidential pattern 15 sequentially outputs a confidential pattern change command at a fixed cycle or at a random cycle, and the confidential pattern selecting unit 16 generates a random sequence code of its own device every time the change command is issued. The time series code {x _n } is received from the unit 12 and the
One secret story pattern is selected and set in the secret story pattern setting section 3.

FIG. 2 shows an example in which the secret story pattern is changed at regular intervals.

In the example of FIG. 2, the 3,7,1,6... Confidential patterns are randomly set sequentially according to the time-series code {x _n }. In the next call, the continuation of the time series code {x _n }
Since the confidential pattern of No. 5, 4,... Is selected, it is impossible to deduce the confidential pattern of the next call even if the previous call is decoded.

FIG. 3 is an explanatory diagram of an example in which the secret story pattern is changed at random intervals.

In the example of FIG. 3, the aforementioned random time-series code {x _n }
In the same way as above, the change cycle is changed randomly using a function whose code is sequentially determined by a certain rule, and the secret story pattern is changed randomly as described above. Can be prevented.

The initialization operation and the user's operation may be a one-touch feeling. For example, if the wireless phone is a parent-child cordless phone, with the slave unit housed in the master unit, press the confidential button to end with a chime, or use common portable media such as an IC card. What is necessary is just to set an initial parameter to a parent machine and a child machine using it.

4 (a), 4 (b) and 5 are block diagrams showing specific examples in which the above embodiment is applied to a parent-child cordless telephone. FIG. 4 (a) shows the master unit 17, and FIG. 4 (b) shows the slave unit.
18 is shown. However, in this example, an example is shown in which the initial parameter P is automatically set by, for example, a die.

In FIG. 4 (a), the base unit 17 includes a secret unit 19, a radio unit 23 having a control unit 22 and an antenna 5a, and connects a line interface 25 to a public network 24 as a PBX line. Connected through.

The privacy section 21 includes a privacy communication LSI in which a plurality of privacy patterns are stored. The control unit 22 includes a general CPU. The wireless unit 23 includes a transmitting unit and a receiving unit, and a synthesizer for generating a secret speech in accordance with the set secret pattern.

On the other hand, in FIG.
, A control unit 27, a secret talk unit 28, and a transceiver unit 29.

The wireless unit 26 includes a transmitting / receiving unit and a synthesizer. The control unit 25 includes a general CPU. The privacy section 28 includes the privacy communication LSI that is the same as the privacy communication LSI of the base unit 17. The transmitter / receiver unit 29 has a dial key and a display in addition to the transmitter and the receiver.

In FIG. 5 showing the details of the control units 22 and 27 of the two units 17 and 18, a bus 30 has a CPU 31, an ID-ROM 32, a RAM 33, a coding circuit 34, a decoding circuit 35, and an input / output unit (I / O) 36 is connected. The timer 31 is connected to the CPU 31. The CPU 31 includes the secret OS 37 described above.

 FIG. 6 is a state transition diagram of the cordless telephone.

When the initialization is completed in the lower initial mode 38 ', a standby mode 39 is set, and a call process is performed based on a triangular relationship among the mode 39, the connection mode 40, and the call mode.

FIGS. 7 and 8 show the parent-child cordless telephone.
It is a flowchart which shows the initialization method of 17 and 18, and a secret talk system.

Shake the dice in step 701, the determined parameters and initial values of f _p, the condition of the initialization in step 702 is outputted to the slave unit. At this time, the slave unit 18 is housed in the master unit 17, and these conditions do not leak to the outside by radio signals.

At step 706 through step 705, the next random code is set, for example, after a certain time ΔT shown in FIG.
After step 704, a secret story pattern corresponding to the random code is set.

In the example of the pattern setting method shown in FIG. 3, the pattern setting change cycle may be changed according to the random code.

FIG. 8 is a block diagram showing an example of a privacy system in which the present invention is applied to a wireless telephone of a base station and a mobile station.

As shown, the base station 42 includes a secret communication LSI 43 corresponding to the number of lines, and a channel gate 44 for selecting the LSI.
, A control unit 45, and a wireless unit 46 having an antenna 5c, and are connected to the public network 24 via a local line interface 47. The configuration of the mobile station is the same as that of the slave unit 18 in FIG. 4 (b).

In this example, since the base station selects the 1: 1 private communication LSI 43 according to the selected line, the same private communication as that shown in FIGS. 4A and 4B can be performed.

In this example, the secret mode is introduced into a base station and a mobile phone that simultaneously transition between three states of a standby mode, a connection mode, and a call enabled mode, and each time the connection mode for calling and incoming calls is entered. Then, the parameter P of the discrete dynamical system is transmitted from the mobile station to the serving base station to initialize both of the confidential systems, thereby making the confidential pattern in the talkable mode equivalently unique.

FIG. 9 shows a confidential pattern storage unit 10, a synchronization adjustment unit 14, a parameter setting unit 11, a random sequence code generation unit 12, a sequence code storage unit 47, and a confidential pattern determination / change unit 48 as described above.
This is an example in which a confidential OS consisting of is integrated into an LSI to form a new confidential communication LSI 49.

Thus, the confidential communication LSI as shown in the conventional example
In addition, the secret OS as shown in the above embodiment is integrated into one
By using an LSI, it can be applied to various wireless devices and cost reduction can be achieved.

As shown in the above-described embodiments, the present invention allows a pair of wireless devices for the purpose of performing communication between the parties to simultaneously transmit a plurality of arbitrarily designed and set secret patterns from a plurality of confidential patterns. A confidential system that selectively sets and sets two confidential speech patterns, converts the original speech into a confidential speech signal on the transmitter side, transmits the confidential speech signal by radio signal, and restores the confidential speech signal received on the receiver side to the original speech. In this wireless system, a separate operating system (OS) for further controlling this complete confidential communication system in the call mode is provided in the wireless system, and the confidential pattern set in the OS is successively used during the call. And set.

I will be in charge of dynamic control
At that time, some random process (Stocha) is used to determine the following constraint requirements, which pattern to change to, and when to change it.
stic Process).

No information or signal that allows other wireless stations to estimate which pattern to change to next is not placed on the radio in the call mode.

Is controlled by imposing
Even with the use of LSI, even if this is mass-produced, there is almost no possibility of eavesdropping, and you can talk with confidence as a personal communication means.

[Effects of the Invention] As described above, the present invention is a confidential communication system and a confidential communication LSI of a wireless telephone as described in the claims, so that the confidential pattern can be randomly changed one after another. Eavesdropping by three parties can be prevented.

Moreover, the random change of the secret story pattern is performed by using a random sequence code determined under a certain rule, and this certain rule is initialized without inorganic communication including part or all of the parameter change. Since the same code sequence is used every time a call is made starting from the time point of initial setting, it is impossible for the third party to reproduce the same random sequence, and wiretapping can be prevented reliably.

[Brief description of the drawings]

FIG. 1 is a block diagram of a confidential communication system according to an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams showing the operation thereof, and FIG.
The figure shows a block diagram of a parent-child telephone to which the above embodiment is applied.
FIG. 6 is a block diagram showing details of a control unit of the parent-child telephone, FIG. 6 is an explanatory diagram of state transition of the parent-child telephone, FIG. 7 is a flowchart showing a secret communication system of the parent-child telephone, and FIG. FIG. 9 is a block diagram showing an embodiment of a secret communication LSI. 3 ... Secret talk pattern setting unit 10 ... Secret talk pattern storage unit 12 ... Random sequence code generation unit 15 ... Secret talk pattern change instructing unit 16 ... Secret talk pattern selection unit 49 ... Secret talk LSI

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Sekiguchi 3-24-11 Setagaya, Setagaya-ku, Tokyo (56) References JP-A-64-10750 (JP, A) HABUTSU, Y. NISH IO, I.N. SASASE, "A Secret Key Cryptosystem using a Chaotic Map," The Transactions of the IEICE, Vol. E73, no. 7, (Jul. 1990); 1041-1044 (58) Fields investigated (Int.Cl. ⁶ , DB name) H04L 9/00-9/38 H04K 1/00-3/00 G09C 1/00-5/00 H04B 7/24-7 / 26 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A confidential system in which an original voice is converted into a confidential voice on a transmitter side and transmitted as a radio signal, and a radio signal received on a receiver side is restored. A confidential pattern storage unit for storing, a random sequence code generating unit for sequentially generating a random sequence code determined under a certain rule by a function of a discrete dynamical system using time as an initial value, and a confidential pattern A secret pattern change instruction unit that outputs a change instruction based on the cycle of the random sequence code; and a random code generated by the random sequence code generation unit when a change command is output from the secret pattern change instruction unit. A secret story pattern selection for selecting and setting one secret story pattern different from the previous one from a plurality of secret story patterns stored in the secret story pattern storage unit by using A secrecy voice conversion unit for converting an original voice into a confidential voice using the confidential pattern selected and set by the confidential pattern selection setting unit and outputting the converted signal as a wireless signal; And a sound restoring unit for restoring a signal and outputting the restored sound as a restored sound.