Audio communication system and method based on fractional order chaotic system

Abstract

The application relates to an audio communication system and method based on a fractional order chaotic system, which encrypts an audio signal through dynamic signal amplitude adjustment and anti-synchronization of a fractional order chaotic system, and multiple utilization of a channel signal, which is used for synchronization and amplitude adjustment of the signal, and is first applied to signal encryption of an audio communication system by simultaneously using signal amplitude adjustment, a fractional order chaotic system and anti-synchronization, so that even if a decryption system is known, the encrypted signal cannot be cracked, thereby greatly improving the encryption security of the audio communication system and the security of voice communication.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of communication encryption and decryption technology, and relates to an audio communication system and method based on a fractional-order chaotic system. BACKGROUND

[0002] The chaotic system was first proposed in 1961, and the system is named Lorenz system and is used for weather prediction. The chaotic system has two significant features. One is initial value sensitivity. After a long time of iterative evolution, a slight change in any parameter or initial value of the system will lead to completely different waveforms, similar to the butterfly effect. The other is randomness. The phase diagram of the chaotic system will never repeat. The two characteristics of the chaotic system can be used to encrypt analog signals, such as audio signals. This paper also relates to the synchronization of the chaotic system. The encryption system is used as a driving system, and a suitable response system is designed by using the synchronization theory of the chaotic system, so that the encrypted signal can be decrypted. In the existing scheme of using the chaotic system to encrypt the audio signal, the signal of the response system is usually directly used to restore the original signal, and most of the chaotic systems are integer-order chaotic systems. If the response system is known, the encrypted signal can be easily cracked, and there is a technical problem of low encryption security. SUMMARY

[0003] In view of the problems in the above-mentioned traditional technology, the application provides an audio communication system based on a fractional-order chaotic system and an audio communication method based on a fractional-order chaotic system, which can effectively improve the encryption security.

[0004] In order to achieve the above-mentioned purpose, the embodiments of the application adopt the following technical solutions:

[0005] On the one hand, an audio communication system based on a fractional-order chaotic system is provided, which comprises an encryption module, a decryption module and a base station. The encryption module is in communication connection with the decryption module through the base station. The encryption module comprises an encryption system designed based on a fractional-order chaotic system, the decryption module comprises a decryption system designed based on a fractional-order chaotic system, and the encryption module and the decryption module are each provided with an amplitude adjuster.

[0006] After the original voice signal is converted into digital signals by AD conversion and then subjected to additive encryption in the encryption system, the amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system. The encrypted signal after amplitude adjustment is converted into an encrypted voice signal in the form of a digital baseband signal and is transmitted to the opposite end through the base station. The encryption system transmits a synchronization signal to the decryption system in the form of a digital signal through the base station. The phase of the synchronization signal is opposite to the phase of the encrypted signal.

[0007] The amplitude adjuster of the decryption module receives the digital baseband signal from the base station, adjusts the signal amplitude of the encrypted voice signal according to the signal amplitude gain of the synchronization signal, and then sends the encrypted voice signal into the decryption system for decryption. The decrypted signal is converted into the original voice signal through DA conversion.

[0008] In another aspect, an audio communication method based on the fractional order chaotic system is also provided, and the audio communication method is based on any one of the audio communication systems based on the fractional order chaotic system. The audio communication method comprises the steps of:

[0009] The original voice signal is converted into the encrypted signal through the AD conversion and the additive encryption of the encryption system.

[0010] The amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system.

[0011] The encrypted signal after the amplitude adjustment is converted into the encrypted voice signal in the form of the digital baseband signal and is transmitted to the opposite end through the base station. The encryption system transmits the synchronization signal to the decryption system in the form of the digital signal through the base station, and the phase of the synchronization signal is opposite to the phase of the encrypted signal.

[0012] One of the above technical solutions has the following advantages and beneficial effects:

[0013] The audio communication system and method based on the fractional order chaotic system use the fractional order chaotic system to dynamically adjust the signal amplitude and use the anti-synchronization to encrypt the audio signal, and the channel signal is used multiple times, which is used for both the synchronization and the signal amplitude adjustment. The signal amplitude adjustment, the fractional order chaotic system and the anti-synchronization are simultaneously applied to the signal encryption of the audio communication system for the first time. Even if the decryption system is known, the encrypted signal cannot be cracked, so that the encryption security of the audio communication system is greatly improved, and the security of the voice communication is improved. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0015] Figure 1 The working block diagram of the encryption and decryption module of the audio communication system based on the fractional order chaotic system in one embodiment;

[0016] Figure 2 The first level coefficient calculation block diagram of the response system in one embodiment;

[0017] Figure 3A second stage coefficient calculation block diagram for a response system in one embodiment;

[0018] Figure 4 A third stage coefficient calculation block diagram for a response system in one embodiment;

[0019] Figure 5 A state variable calculation block diagram in one embodiment x 1( t ) calculation block diagram in one embodiment;

[0020] Figure 6 A flowchart of an audio communication method based on a fractional order chaotic system in one embodiment. DETAILED DESCRIPTION

[0021] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0022] It should be noted that the reference herein to "embodiments" means that the specific features, structures or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase is shown at various places in the specification does not necessarily mean the same embodiment, nor is it independent or alternative to other embodiments. Those skilled in the art can understand that the embodiments described herein can be combined with other embodiments. The term "and / or" used herein refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0023] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0024] Chaotic system has strong initial value sensitivity and randomness. Slight change in parameters will produce completely different waveforms, so it has strong attack resistance and is widely used in encryption field. Generally, the derivative of differential equation is an integer 1. In fact, this number can be a fraction. The introduction of fractional order makes the system obtain more abundant dynamic characteristics. There are three common methods to solve f chaotic system. The synchronization theory of chaotic system is the basic theory of encryption and decryption. After synchronization design, the encryption system and the decryption system can achieve synchronization, that is, the waveform of the decryption system can be used to decrypt the encrypted signal. In the existing scheme of using chaotic system to encrypt audio signal, the original signal is usually recovered by directly using the signal of the response system (i.e. the decryption system). If the response system is known, the encrypted signal can be cracked.

[0025] In one embodiment, as shown in Figure 1 An audio communication system based on fractional order chaotic system is provided, which includes an encryption module, a decryption module and a base station. The encryption module is in communication connection with the decryption module through the base station. The encryption module includes an encryption system designed based on fractional order chaotic system. The decryption module includes a decryption system designed based on fractional order chaotic system. Both the encryption module and the decryption module are provided with an amplitude adjuster. After the original voice signal is converted into digital signal by AD conversion and then subjected to additive encryption in the encryption system, the amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system, and the encrypted voice signal in the form of digital baseband signal after amplitude adjustment is transmitted to the opposite end through the base station; the encryption system transmits the synchronization signal to the decryption system in the form of digital signal through the base station, and the phase of the synchronization signal is opposite to that of the encrypted signal.

[0026] At the communication opposite end, after the amplitude adjuster of the decryption module receives the digital baseband signal from the base station, the signal amplitude of the encrypted voice signal is adjusted according to the signal amplitude gain of the synchronization signal, and then the signal is sent into the decryption system for decryption. The decrypted signal is converted into the original voice signal by DA conversion.

[0027] It can be understood that the amplitude of the output signal of the encryption system is processed in the embodiment, and stronger attack resistance can be obtained, that is, the amplitude of the signal is encrypted in the embodiment, and the signal amplitude gain A is generated by mapping to a reasonable range through the chaotic system. The phase of the synchronization signal used for decryption is opposite to that of the encrypted signal in the anti-synchronization, and the security degree is higher. In this way, the fractional order chaotic system, anti-synchronization and amplitude adjustment are applied to the encryption of audio signal at the same time for the first time in the embodiment, and the encrypted signal cannot be cracked even if the decryption system is known.

[0028] As shown in Figure 1The shown is the working block diagram of the encryption and decryption module in the system. In voice communication, the original voice signal output by the communication device A enters the encryption system after AD (analog-digital) conversion, is encrypted, and then is subjected to amplitude encryption processing by the amplitude adjuster according to the signal amplitude gain generated by the system to become a digital baseband signal encrypted and amplitude-adjusted, and finally is modulated into a high-frequency radio frequency signal by the radio frequency front end and sent to the base station in a wireless manner for transmission between base stations. When the user side receives the encrypted voice signal, the encrypted voice signal is demodulated by the radio frequency front end on the user side, decrypted by the amplitude adjuster and the decryption system in turn, and then converted into the original voice signal by DA (digital-analog) conversion and received by the user end (such as the communication device B). At the same time, the signals of the encryption system need to be transmitted to the decryption system through different channels for synchronization and amplitude adjustment of the decryption system, and the form of signal transmission is a digital signal. Figure 1 The dashed portion is the amplitude adjuster newly added in the embodiment, which forms the improved encryption module and decryption module with the improved encryption system and decryption system, respectively. The communication device A, the communication device B, the radio frequency, and the base station are parts of the existing system, which will not be described in detail in the specification.

[0029] The above audio communication system based on the fractional order chaotic system uses the fractional order chaotic system to perform dynamic signal amplitude adjustment and anti-synchronization for audio signal encryption, and multiple uses of the channel signal, which is used for synchronization and amplitude adjustment of the signal. It is the first time to simultaneously apply the signal amplitude adjustment, the fractional order chaotic system, and the anti-synchronization to the signal encryption of the audio communication system. Even if the decryption system is known, the encrypted signal cannot be cracked, thereby greatly improving the encryption security of the audio communication system and the security of voice communication.

[0030] In one embodiment, the Adomian decomposition method is used to discretize and solve the system, and a digital circuit is designed. The Adomian decomposition method is an analytical-numerical hybrid method for solving linear and nonlinear differential equations, which is particularly suitable for fractional order differential equations and nonlinear system analysis.

[0031] The synchronization of the chaotic system needs to be driven by the driving system and the response system, Figure 1 The encryption system in the above formula is the driving system, and the decryption system is the response system. The encryption system uses the chaotic system shown in formula (1):

[0032] (1)

[0033] wherein, D is a fractional order operation operator, x 1、 y 1and z 1respectively represent the state variables of the driving system, qis the fractional order (0 < q < 1). A controller is added to the drive system as the response system:

[0034] (2)

[0035] where x 2. y 2 and z 2 respectively represent the state variables of the response system. u 1, u 2 and u 3 respectively represent the controllers added to each path of the response system. Add equations (1) and (2):

[0036] (3)

[0037] Let the error e 1 = x 1 + x 2, e 2 = y 1 + y 2, e 3 = z1 + z2, then:

[0038] (4)

[0039] Let the error function V = e 1 D x , D , y , -y , q , e , y , e , e , y , q , e , y , D , u , -x , D , e , u , 2 , e , u , u , e , 2 , e , e , q , e , e , e , e , u e 1 + e 2 D q e 2 + e 3 D q e 3 = e 1( e 2 - x 2 + u 1) + e 2(- e 1 + y 1z1 + y 2z2 + u 2) + e 3(2 - y 1 2 - y 2 2 + u 3), when u 1 = - e 2 -x 1, u 2 = e 1 -y1 - z1 -y 2 - z2- e 2, u 3= y 1 2 +y 2 2 -2- e At time 3, the error function V =- e 1 2 - e 2 2 - e 3 2 <0, thus making the error function V Converging to 0, the driving system and the response system become antisynchronous, from which the expression for the response system can be obtained:

[0040] (5)

[0041] The Adomian decomposition method is used to discretize and solve the driving system and response system (expression). Equation (6) is the equation of the discretized driving system:

[0042] (6)

[0043] in, x 1( t 0) y 1( t 0) and z1( t 0) represents the initial values ​​of each state variable in the chaotic system. For the Gamma function, ( t - t 0) is the step size for solving the problem. h Set to 0.01s. , and These are the coefficients of the decomposition. = x 1( t 0), = y 1( t 0), =z1( t Let 0), and let the series of the decomposition be... N =3, then:

[0044] (7)

[0045] (8)

[0046] (9)

[0047] Similarly, the equation of the response system can be solved. N The greater, the higher the solution accuracy, the more computing resources required, can be according to the actual calculation needs of the value.

[0048] In one embodiment, the digital circuit corresponding to the encryption system is composed of adders and multipliers.

[0049] It can be understood that the fractional order of the system in the chaotic state q The range (0 q <1) is determined by the amplitude angle of the equilibrium point of equation (1), and the right side of equation (1) is set to 0, and no analytical solution is found, indicating that the system has no equilibrium point and is in a chaotic state, q Any value in (0, 1) can be taken. Let q = 0.95, the initial value ( x 1( t 0), y 1( t 0), z1( t 0), x 2( t 0), y 2( t 0), z2( t 0)) = (0.1, 0.1, 0.1, -0.1, -0.2, -0.3), using fixed-point notation, using adders and multipliers to complete the digital circuit design of the driving system and the response system, the improved encryption system and decryption system can be realized, and the digital circuit design corresponding to equation (7) is shown in Figure 2 , wherein C represents the clock period at which the calculation is performed, mul represents the multiplier, add represents the adder, all decomposition coefficients and constants used are stored in registers, / / represents truncation, and represents negation.

[0050] The digital circuit design corresponding to equation (8) is shown in Figure 3 , wherein << represents left shift. The digital circuit block diagram corresponding to equation (9) is shown in Figure 4 . The digital circuit block diagram corresponding to equation (6) is shown in Figure 5 , taking the x 1 path as an example, the result of each calculation is used as the initial value for the next calculation, and the iteration is performed in this way. Since x 1, y 1 and z1 path are chaotic signals, any path can be selected, for example, the x 1 path is selected here, the original speech signal at the sending end is additively encrypted, and the response signal of the corresponding path is selected at the receiving end to decrypt.

[0051] Further, the response system can also be designed with corresponding digital circuit, so that the structure of the decryption system corresponds to and logically matches the structure of the encryption system, ensuring that the decryption process is the inverse of the encryption process.

[0052] The signals of the chaotic system are within a certain range. Optionally, a channel is selected, for example, the channel 1 is selected here. y 1 channel, after mapping to a reasonable positive value range, for example, the positive value range (0.5, 1.5) is selected here, the signal amplitude gain of the generated signal is A The amplitude of the encrypted signal is adjusted. During decryption, the corresponding response signal is selected for amplitude adjustment to decrypt.

[0053] In one embodiment, as Figure 6 shown, an audio communication method based on a fractional order chaotic system is also provided, which is based on any of the above audio communication systems based on a fractional order chaotic system. The audio communication method can include the following steps S12 to S16:

[0054] S12, the original voice signal is converted by AD into the encryption system for additive encryption;

[0055] S14, the amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system;

[0056] S16, the encrypted voice signal in the form of the encrypted signal after amplitude adjustment is converted into a digital baseband signal and transmitted to the opposite end through the base station; the encryption system transmits a synchronization signal in the form of a digital signal to the decryption system through the base station, and the phase of the synchronization signal is opposite to the phase of the encrypted signal.

[0057] The above audio communication method based on a fractional order chaotic system encrypts the audio signal by using the fractional order chaotic system for dynamic signal amplitude adjustment and anti-synchronization, and multiple uses of the channel signal for synchronization and signal amplitude adjustment. It is the first time to apply signal amplitude adjustment, fractional order chaotic system and anti-synchronization to signal encryption of the audio communication system at the same time, even if the decryption system is known, the encrypted signal cannot be cracked, thereby greatly improving the encryption security of the audio communication system and the security of voice communication.

[0058] In one embodiment, the above audio communication method based on a fractional order chaotic system can further include the following steps: the amplitude adjuster of the decryption module adjusts the signal amplitude of the encrypted voice signal according to the signal amplitude gain of the synchronization signal after receiving the digital baseband signal from the base station; the decryption system decrypts the encrypted voice signal after signal amplitude adjustment; and the decrypted signal is converted into the original voice signal by DA.

[0059] It can be understood that the explanation of the features in the audio communication method based on the fractional order chaotic system can be understood in the same way as the corresponding explanation in the audio communication system based on the fractional order chaotic system.

[0060] All the optional technical solutions described above can be combined to form optional embodiments of the present application, which will not be described here.

[0061] The technical features of the above embodiments can be combined in any way. To make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combination of the technical features does not exist, it should be considered as the scope of the present application.

[0062] The above embodiments only express several embodiments of the present application, which are described in detail and specifically, but should not be considered as a limitation to the scope of protection. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of protection of the present application.

Claims

1. An audio communication system based on fractional order chaotic system, characterized in that, The system comprises an encryption module, a decryption module and a base station, the encryption module is connected with the decryption module through the base station, the encryption module comprises an encryption system designed based on a fractional order chaotic system, the decryption module comprises a decryption system designed based on the fractional order chaotic system, and the encryption module and the decryption module are both provided with an amplitude adjuster; After the original voice signal is converted into a digital signal through AD conversion and then subjected to additive encryption in the encryption system, the amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system, and the encrypted signal after amplitude adjustment is converted into an encrypted voice signal in the form of a digital baseband signal and then transmitted to the opposite end through the base station; The encryption system transmits a synchronization signal to the decryption system in the form of a digital signal through the base station, and the phase of the synchronization signal is opposite to that of the encrypted signal; After receiving the digital baseband signal from the base station, the amplitude adjuster of the decryption module adjusts the signal amplitude of the encrypted voice signal according to the signal amplitude gain of the synchronization signal and then sends the encrypted voice signal into the decryption system for decryption, and the signal after decryption of the decryption system is converted into the original voice signal through DA conversion.

2. The audio communication system based on fractional order chaotic system according to claim 1, wherein, The encryption system discretized by the Adomian decomposition method is as follows: wherein, x 1( t ), y 1( t ) and z 1( t ) are the values of the state variables of the chaotic system at the time instant t , x 1( t 0), y 1( t 0) and z 1( t 0) are the initial values of the state variables of the chaotic system, is the Gamma function, t - t 0 is the step of the solution, , and are the coefficients of the decomposition, respectively.

3. The audio communication system based on fractional order chaotic system according to claim 2, wherein, The digital circuit corresponding to the encryption system is composed of an adder and a multiplier.

4. The audio communication system based on fractional order chaotic system according to any one of claims 1 to 3, characterized in that, The structure of the decryption system corresponds to and is logically matched with the structure of the encryption system.

5. An audio communication method based on a fractional order chaotic system, characterized in that, The audio communication system based on the fractional order chaotic system according to any one of claims 1 to 4, the audio communication method comprises the steps of: The original voice signal is converted into a digital signal through AD conversion and then subjected to additive encryption in the encryption system; The amplitude adjuster of the encryption module adjusts the signal amplitude of the encrypted signal according to the signal amplitude gain generated by the encryption system; The encrypted signal after amplitude adjustment is converted into an encrypted voice signal in the form of a digital baseband signal and then transmitted to the opposite end through the base station; The encryption system transmits a synchronization signal to the decryption system in the form of a digital signal through the base station, and the phase of the synchronization signal is opposite to that of the encrypted signal.

6. The audio communication method based on fractional order chaotic system according to claim 5, characterized in that, The method further comprises the steps of: After receiving the digital baseband signal from the base station, the amplitude adjuster of the decryption module adjusts the signal amplitude of the encrypted voice signal according to the signal amplitude gain of the synchronization signal; The decryption system decrypts the encrypted voice signal after signal amplitude adjustment; The signal after decryption is converted into the original voice signal through DA conversion.

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