Voice encryption and decryption method based on fractional order chaotic system synchronization

Abstract

The present invention relates to the field of communication security technology, and in particular to a voice encryption and decryption method based on fractional-order chaotic system synchronization. The method comprises the following steps: selecting an m-dimensional fractional-order chaotic system as a driving system to generate a chaotic sequence, performing multiple XOR operations on a preprocessed voice signal and the chaotic sequence, and then using a logistic mapping sequence to index and polarity scramble the audio signal to complete encryption; constructing an n-dimensional response system and an error system, and designing a fractional-order integral sliding mode controller to achieve predefined time synchronization; after receiving the encrypted audio, performing an inverse operation according to a corresponding chaotic sequence generated by the response system to perform decryption and restoration; achieving predefined time synchronization of non-identical fractional-order chaotic systems through a fractional-order integral sliding mode controller, and combining multiple XOR operations, polarity scrambling, and index scrambling to perform high-intensity encryption and decryption on voice data, thereby significantly improving the synchronization efficiency and robustness of the system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication security, in particular to a voice encryption and decryption method based on synchronization of fractional order chaotic system. BACKGROUND

[0002] With the rapid development of information technology, voice communication is widely used in personal communication, telemedicine, military command and business finance, etc. As a highly sensitive information carrier, voice data faces increasingly severe security challenges during transmission and storage. Especially in applications involving privacy protection and high security requirements, ensuring the integrity and confidentiality of voice information has become a key link in the design of voice communication systems.

[0003] Traditional voice encryption technology is mostly based on fixed algorithm rules for scrambling voice signals. However, with the continuous improvement of computing power and the evolution of cracking technology, the original encryption mechanism gradually exposes problems such as small key space, weak attack resistance, strong decryption reversibility, etc., making it difficult to effectively resist modern security threats. At the same time, although existing chaotic encryption methods have certain complexity, they often rely on initial state or require repeated parameter tuning during chaotic system synchronization, resulting in low synchronization time calculation accuracy, complex controller design, and large decryption delay, which makes it difficult to meet real-time and reliability requirements. SUMMARY

[0004] The present application provides a voice encryption and decryption method based on synchronization of fractional order chaotic system, which realizes fast synchronization between heterogeneous chaotic systems by designing a fractional order integral sliding mode controller with robustness and adjustable settling time, and enhances the strength and dynamics of voice encryption by combining multiple XOR operations and a scrambling mechanism based on Logistic mapping sequence, thereby effectively improving the security, real-time performance and anti-interference ability of voice communication.

[0005] The voice encryption and decryption method based on synchronization of fractional order chaotic system comprises the following steps:

[0006] S1, selecting an m-dimensional fractional order chaotic system as a drive system;

[0007] S2, preprocessing the audio file to be encrypted;

[0008] S3, generating multiple chaotic sequences through the drive system;

[0009] S4, encrypting the preprocessed audio file according to the generated chaotic sequence and Logistic mapping sequence, and transmitting the encrypted audio file;

[0010] S5, selecting an n-dimensional fractional order chaotic system as a response system;

[0011] S6, establishing an error system according to the established driving system and the response system;

[0012] S7, designing a new fractional integral sliding mode controller to realize the synchronization of the driving system and the response system, that is, using the new fractional integral sliding mode controller to make the state of the error system 0;

[0013] S8, after receiving the encrypted audio file, the encrypted audio file is decrypted according to the chaotic sequence generated by the synchronized response system and the Logistic mapping sequence.

[0014] Optionally, the S1 comprises:

[0015] S11, the integrable function The fractional integral of order is defined as:

[0016] ;

[0017] Wherein, , Gamma function, ;

[0018] S12, the Caputo type fractional derivative of the function is defined as:

[0019] ;

[0020] Wherein, , , ;

[0021] When , ;

[0022] S13, according to the definition of Caputo type fractional calculus, the model of m-dimensional fractional driving system is:

[0023] ;

[0024] Wherein, is the fractional order of the system, is the state vector of the system, respectively represent the internal uncertainty and external disturbance of the system, is a known continuous nonlinear function.

[0025] Optionally, the S2 comprises:

[0026] S21, resampling the audio file to be encrypted;

[0027] S22, normalizing the resampled audio file;

[0028] S23, mapping the normalized audio file to 16-bit integer, i.e. range.

[0029] Optionally, the S3 comprises:

[0030] S31, according to the size of the preprocessed audio file, cutting off the state of the driving system after a certain time, generating a plurality of groups of chaotic sequences corresponding to the dimension;

[0031] S32, comparing the length of the preprocessed audio file with the length of the chaotic sequence, if the length of the audio file is greater than the length of the chaotic sequence, then expanding by repeating and superimposing the chaotic sequence until its length exceeds the length of the audio file, and cutting off the part equal to the length of the audio file;

[0032] S33, if the length of the audio file is less than the length of the chaotic sequence, then directly cut off the part equal to the length of the audio file to meet the encryption requirement;

[0033] S34, mapping the values in the chaotic sequence to range, consistent with the audio file.

[0034] Optionally, the S4 comprises:

[0035] S41, performing XOR operation on the audio file and the chaotic sequence for multiple times to complete the primary encryption;

[0036] S42, generating a group of sequences by using Logistic mapping, indexing and scrambling the primary encrypted audio file according to the sequences generated by Logistic mapping in ascending order, and performing polarity scrambling according to the values in the sequences generated by Logistic mapping;

[0037] S43, converting the encrypted voice data into.wav format for transmission.

[0038] Optionally, the response system model is represented as:

[0039] ;

[0040] wherein, is the fractional order of the system, represents the state vector of the system, represent the internal uncertainty and external disturbance of the system, respectively, ​ is a known continuous nonlinear function, is a control input.

[0041] Optionally, the S6 comprises:

[0042] S61, defining a synchronization error between the drive system and the response system states, denoted as:

[0043] ;

[0044] wherein, is a row full rank constant matrix that maps the drive system state space to the response system state space;

[0045] S62, dividing into a synchronization controller and a compensation controller , denoted as:

[0046] ;

[0047] ;

[0048] S63, establishing a mathematical model of the error system, denoted as:

[0049] .

[0050] Optionally, the S7 comprises:

[0051] S71, the sliding surface of the fractional order integral sliding mode controller is denoted as:

[0052] ;

[0053] wherein, and are arbitrary normal numbers, ;

[0054] ;

[0055] S72, the new fractional order integral sliding mode controller is denoted as:

[0056] ;

[0057] wherein, and are arbitrary normal numbers, ;

[0058] ;

[0059] S73, the driving system and the response system will be in the predefined time complete synchronization.

[0060] Optionally, the S8 comprises:

[0061] S81, the encrypted audio file is converted into a 16-bit integer;

[0062] S82, a chaotic sequence with the same length as the audio file is generated according to the response system, and the same number of XOR operations are performed to complete the preliminary decryption;

[0063] S83, a group of sequences is generated according to the Logistic mapping, the audio file after the preliminary decryption is inversely indexed and scrambled according to the sequence generated by the Logistic mapping in ascending order, and the audio file after the decryption is restored to the.wav format according to the value in the sequence generated by the Logistic mapping.

[0064] The beneficial effects of the present application are:

[0065] The present application, by adopting the pre-defined time synchronization control mechanism based on the non-identical fractional order chaotic system, can realize the fast and high-precision synchronization of the driving system and the response system within the preset time, significantly improve the real-time performance and controllability of the voice encryption system, the fractional order integral sliding mode controller has strong robustness and anti-interference ability, and can effectively cope with the internal uncertainty and external disturbance of the system, without relying on the initial conditions, the stability and convergence of the synchronization system are ensured, and reliable support is provided for the encryption and decryption of voice data.

[0066] The present application, by constructing multiple chaotic sequences and combining the Logistic mapping sequence to perform multi-level scrambling processing (including multiple XOR, index scrambling and polarity scrambling) on the voice data, effectively improves the complexity of the key space and the encryption unpredictability, and at the same time realizes high-precision audio restoration through the reversible disturbance structure, is suitable for audio data of different lengths, has good adaptability and universality, and through simulation verification, stable and effective encryption effect is realized under multiple voice samples, and the security of voice communication is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0067] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only illustrate the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0068] Figure 1 The decryption method flowchart of the embodiment of the present application;

[0069] Figure 2 The schematic diagram of random noise with uniform distribution, amplitude of 1.5 and 2.5 encountered by the chaotic system of the embodiment of the present application;

[0070] Figure 3 The schematic diagram of state trajectory of the driving system when the initial value is of the embodiment of the present application;

[0071] Figure 4 The schematic diagram of state trajectory of the response system when the initial value is of the embodiment of the present application;

[0072] Figure 5 The schematic diagram of synchronization error trajectory of the driving system and the response system when the initial value is of the embodiment of the present application;

[0073] Figure 6 The schematic diagram of evolution of each state of the driving system and the response system when the initial value is of the embodiment of the present application;

[0074] Figure 7 The schematic diagram of state trajectory when the initial value is randomly selected for 10 groups, the synchronization error and in of the embodiment of the present application;

[0075] Figure 8 The schematic diagram of synchronization error trajectory corresponding to the setting of different of the embodiment of the present application;

[0076] Figure 9 The schematic diagram of time domain and frequency domain of the original signal of Test1 of the embodiment of the present application;

[0077] Figure 10 The schematic diagram of time domain and frequency domain of Test1 after pretreatment of the embodiment of the present application;

[0078] Figure 11 The schematic diagram of time domain and frequency domain of Test1 after encryption of the embodiment of the present application;

[0079] Figure 12 The schematic diagram of time domain and frequency domain of Test1 after decryption of the embodiment of the present application;

[0080] Figure 13 The schematic diagram of time domain and frequency domain of the original signal of Test2 of the embodiment of the present application;

[0081] Figure 14 The schematic diagram of time domain and frequency domain of Test2 after pretreatment of the embodiment of the present application;

[0082] Figure 15 This is a time domain diagram and a frequency domain diagram of the encrypted Test2 according to an embodiment of the present invention;

[0083] Figure 16 This is a time domain diagram and a frequency domain diagram of the decrypted Test2 according to an embodiment of the present invention. DETAILED DESCRIPTION

[0084] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0085] like Figures 1-16 As shown, the voice encryption and decryption method based on fractional-order chaotic system synchronization includes the following steps:

[0086] (1) Select an m-dimensional fractional-order chaotic system as the driving system;

[0087] (2) Preprocessing the audio file to be encrypted;

[0088] (3) Generate multiple chaotic sequences by driving the system;

[0089] (4) encrypting the pre-processed audio file according to the chaotic sequence and logistic mapping sequence generated in step (3), and transmitting the encrypted audio file;

[0090] (5) Select an n-dimensional fractional-order chaotic system as the response system;

[0091] (6) establishing an error system based on the drive system and response system established in steps (1) and (5);

[0092] (7) Design a new fractional-order integral sliding mode controller to achieve synchronization between the drive system and the response system, that is, use the controller Let the state of the error system be 0;

[0093] (8) After receiving the encrypted voice, the encrypted audio file is decrypted according to the chaotic sequence and logistic mapping sequence generated by the synchronized response system.

[0094] The definition of fractional-order calculus in step (1) and the model of the fractional-order drive system are as follows:

[0095] Definition 1: Let the integrable function of The fractional integral is defined as follows:

[0096] ;

[0097] where , is the gamma function. It is defined as:

[0098] ;

[0099] Definition 2: Caputo-type fractional derivative of the function can be defined as:

[0100] ;

[0101] where , . In particular, when , we have ;

[0102] According to the definition of Caputo-type fractional calculus, the model of m-dimensional fractional-order driven system is:

[0103] (1.1)

[0104] where is the fractional order of the system, represents the state vector of the system; represent the internal uncertainty and external disturbance of the system, respectively. is a known continuous nonlinear function.

[0105] Step (2) requires preprocessing of the audio file. First, the original audio is resampled to reduce the amount of audio data and improve encryption speed. Then the audio signal is normalized to ensure data consistency. Finally, the normalized data is mapped to 16-bit integers (i.e. range ) to facilitate subsequent encryption processing.

[0106] Step (3) extracts the state of the driving system at a certain time after the synchronization time according to the size of the speech data, generating several groups of chaotic sequences of corresponding dimensions. Compare the length of the speech data with the length of the chaotic sequence. If the length of the speech data is greater than the length of the chaotic sequence, expand it by repeating and superimposing the chaotic sequence until its length exceeds the length of the speech data, and then cut off the part equal to the length of the speech data for subsequent encryption. If the length of the speech data is less than the length of the chaotic sequence, directly cut off the part equal to the length of the speech data to meet the encryption requirements. Through the above method, the length of the chaotic sequence is consistent with the length of the speech data. The values in the chaotic sequence are usually in a very small range, and they also need to be mapped to Range, consistent with the audio data.

[0107] Step (4) completes the initial encryption by performing multiple XOR operations between the voice data and the chaotic sequence. Then, a set of sequences is generated using the Logistic mapping. The initial encrypted audio data is indexed and shuffled in ascending order according to the sequences generated by the Logistic mapping, and the polarity is shuffled according to the median value in the sequences generated by the Logistic mapping. Finally, the encrypted voice data is converted into.wav format for transmission.

[0108] Step (5) selects the corresponding n-dimensional fractional order response system model as:

[0109] (1.2)

[0110] where, is the fractional order of the system, represents the state vector of the system; represent the internal uncertainty and external disturbance of the system, respectively. is a known continuous nonlinear function, and the control input is .

[0111] Steps (6) and (7) design a new fractional integral sliding mode controller to achieve synchronization between the drive system and the response system. First, the dimension difference between the drive system (1.1) and the response system (1.2) is handled by using the mapping matrix , and the synchronization error can be defined as . Here, we need to divide the controller into and two parts, . The compensation controller is designed in advance to handle the order difference between the drive system (1.1) and the response system (1.2), which will be designed later to achieve predefined time synchronization of non-identical fractional order chaotic systems. Then, we have the error system:

[0112] (1.3)

[0113] where is a row full rank constant matrix that maps the drive system state space to the response system state space.

[0114] Since the controller in step (7) is a sliding mode controller, the sliding surface will be designed as:

[0115] ​(1.4)

[0116] Here, and are arbitrary positive constants,

[0117] ;

[0118] The new fractional integral sliding mode controller is designed as:

[0119] (1.5)

[0120] Here, and are arbitrary positive constants,

[0121] ;

[0122] The drive system and the response system will be synchronized at a predefined time .

[0123] The following assumptions, properties and lemmas are needed to prove the synchronization.

[0124] Assumption 1: For all , there exist constants and such that for any internal uncertainty and external disturbance, the following condition is always satisfied:

[0125] ;

[0126] Property 1: For and , the following property exists

[0127] ;

[0128] If , then .

[0129] Lemma 1: If , we have ;

[0130] Lemma 2: If a continuous function satisfies:

[0131] 1) ;

[0132] 2) ;

[0133] 3) For any , there exist and satisfies:

[0134] ;

[0135] Then is pre-defined time stable, while is pre-defined time.

[0136] The proof for the fractional order sliding surface is as follows:

[0137] Construct a suitable Lyapunov function as follows:

[0138] (1.6)

[0139] Taking the derivative of , according to property 1, we have:

[0140] (1.7)

[0141] By inequality lemma 1, we can conclude that

[0142] (1.8)

[0143] According to lemma 2, the error state of the system will converge to 0 from the sliding surface within a pre-defined time . The proof for the fractional order sliding surface is completed.

[0144] The proof for the new fractional order integral sliding mode controller is as follows:

[0145] Construct a suitable Lyapunov function as follows:

[0146] (1.9)

[0147] Taking the derivative of and bringing the controller (1.5) into it, we have:

[0148] (1.10)

[0149] According to assumption 1 and lemma 1, we can further conclude that:

[0150] (1.11)

[0151] Here, according to lemma 2, the error state of the system will reach the sliding surface (1.4) within a pre-defined time . The drive system (1.1) and the response system (1.2) will achieve synchronization within a pre-defined time . The proof for the controller is completed.

[0152] Step (8) converts the encrypted voice into 16-bit integers (i.e. range ). Then, a chaotic sequence of the same length as the voice data is generated according to the response system, and then the XOR operation is performed the same number of times to complete the preliminary decryption. Then, a set of sequences is generated according to the Logistic mapping, and the audio data after the initial decryption is inversely indexed and scrambled according to the sequence generated by the Logistic mapping in ascending order, and the inverse polarity scrambling is performed according to the sequence generated by the Logistic mapping. Finally, the decrypted voice data is restored to the.wav format. The decryption process is completed.

[0153] Example 1:

[0154] Please refer to Figure 1 , Figure 1 is the overall framework diagram of the present application. The present application provides a voice encryption and decryption method based on synchronization of fractional order chaotic system. First, the pre-defined time synchronization control of non-identical fractional order chaotic system is introduced.

[0155] A four-dimensional fractional hyperchaotic Lorenz system is selected as the driving system:

[0156] (1.12)

[0157] A three-dimensional fractional inverse butterfly chaotic system is selected as the response system:

[0158] (1.13)

[0159] Let the internal uncertainty be The uniformly distributed random noise with amplitude of 1.5 and 2.5 is selected as the external disturbance, as shown in Figure 2 . Figure 3 and 4 show the state trajectories of the driving system (1.12) and the response system (1.13) when the initial value is . The matrix K is arbitrarily selected as follows:

[0160]

[0161] According to assumption 1, we can deduce that When we set and then The synchronization error of the driving system (1.12) and the response system (1.13) will be Converges to 0, and the results are shown in Figure 5

[0162] The evolution of each state of the drive system (1.12) and the response system (1.13) is shown in Figure 6 We randomly select 10 groups of initial values, and the synchronization error of the drive-response system can still converge within 0.2s, and the results are shown in Figure 7 By arbitrarily selecting different When external disturbances and internal uncertainties are not considered, the drive-response system can always achieve synchronization within the corresponding The results are shown in Figure 8

[0163] The present application can select appropriate chaotic systems as the drive system and the response system according to the size of the voice data, and the fractional order integral sliding mode controller designed in the present application can always achieve synchronization.

[0164] Next, the encryption and decryption process in Example 1 is described in detail.

[0165] Two audio files are selected as test samples. The test audio Test1 is the call of a popular person "IKUN.wav", and the audio file format is WAV, the sampling frequency is unknown, and the duration is about 2 seconds. The test audio Test2 is a music work "Fairy Tale Town.wav", and the audio file format is WAV, the sampling frequency is 44100Hz, the bit rate is 32kbps, and the duration is about 43 seconds.

[0166] The test audio is resampled at a sampling frequency of 8000Hz to reduce the data amount of the audio. The audio is normalized and then mapped to the range to ensure data consistency.

[0167] After selecting a four-dimensional fractional order hyperchaotic Lorenz system as the drive system, the state between 1s and 2s is intercepted as a chaotic sequence. Here, under the action of the mapping matrix K, the chaotic system will be reduced to 3 dimensions, and 3 groups of chaotic sequences will be generated.

[0168] The length of the voice data is obtained, and the length of the voice data is compared with the length of the chaotic sequence. If the length of the voice data is greater than the length of the chaotic sequence, the chaotic sequence is expanded by repeating and superimposing, until its length exceeds the length of the voice data, and the part with the same length as the voice data is intercepted for subsequent encryption; if the length of the voice data is less than the length of the chaotic sequence, the part with the same length as the voice data is directly intercepted to meet the encryption requirement. The values in the chaotic sequence are usually in a very small range, and they also need to be mapped to the range to be consistent with the audio data.

[0169] ​​Because the drive system (1.12) is reduced to 3 dimensions by the mapping matrix K, the voice data is first XOR operated with 3 groups of chaotic sequences for 3 times for preliminary encryption. A group of sequences is generated according to the Logistic mapping. The mathematical form of the Logistic mapping is as follows:

[0170]

[0171] The parameter r is set to 3.9999, the initial value is set to 0.5.

[0172] According to the ascending order of the sequences generated according to the Logistic mapping, the voice data after the preliminary encryption is indexed and scrambled, and the polarity is scrambled according to the value in the sequence generated according to the Logistic mapping. Finally, the encrypted voice data is converted into the.wav format for transmission.

[0173] A three-dimensional fractional order inverse butterfly chaotic system is selected as the response system. Under the action of the controller, the drive system and the response system complete synchronization, and the state of the response system from 1s to 2s is intercepted as a chaotic sequence.

[0174] In this example, the state after 0.2s must be intercepted to generate a chaotic sequence, because the drive system and the response system will be synchronized after 0.2s, otherwise the decryption will fail. The appropriate length can also be intercepted according to the size of the audio data.

[0175] After receiving the encrypted voice data, the audio file is converted into a 16-bit integer (i.e. the range is generated according to the response system after synchronization. Since the response system is 3-dimensional, 3 groups of chaotic sequences can be generated. Here, the voice data also needs to be compared with the chaotic sequences to make their lengths the same, and the chaotic sequences also need to be mapped to the range. Then the data to be decrypted is XOR operated with the chaotic sequences for 3 times, and the encrypted voice is inversely indexed and scrambled according to the Logistic mapping sequence, to complete the decryption of the voice signal. Finally, it is restored to the.wav format.

[0176] Figure 9 The original signal time domain graph and frequency domain graph of the test audio Test1 are shown; Figure 10 The time domain graph and frequency domain graph of the audio after preprocessing are shown; Figure 11 The time domain graph and frequency domain graph of the audio after encryption are shown; Figure 12 The time domain graph and frequency domain graph of the audio after decryption are shown. Figure 13 The original signal time domain graph and frequency domain graph of the test audio Test2 are shown; Figure 14 The time domain graph and frequency domain graph of the audio after preprocessing are shown; Figure 15The time-domain graph and the frequency-domain graph of the decrypted audio are shown. Figure 16 The time-domain graph and the frequency-domain graph of the decrypted audio are shown.

[0177] In Example 1, the synchronization accuracy will have an error range of about 0.02, resulting in slight differences in the time-domain graph and the frequency-domain graph of the audio before and after decryption. However, this error has little effect on the overall quality and playing effect of the decrypted audio.

[0178] By observing the synchronization error trajectory of the driving system and the response system, it is proved that the controller proposed in the application can effectively realize the synchronization of the chaotic system within a predetermined time. By observing the time-domain graph and the frequency-domain graph of the test audio and listening to the encrypted and decrypted audio, it is proved that the application can effectively encrypt and decrypt audio information.

[0179] The application covers any substitution, modification, equivalent method and scheme made within the essence and scope of the application. In order to make the public have a thorough understanding of the application, specific details are described in the following preferred embodiments of the application, and the application can also be fully understood without the description of these details for those skilled in the art. In addition, in order to avoid unnecessary confusion to the essence of the application, well-known methods, processes, procedures, elements and circuits, etc. are not described in detail.

[0180] The above is only the preferred embodiment of the application, and it should be pointed out that for ordinary skilled in the art, without departing from the principle of the application, a number of improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the application.

Claims

1. A voice encryption and decryption method based on fractional-order chaotic system synchronization, characterized in that: The following steps are involved: S1, select an m-dimensional fractional-order chaotic system as the driving system; S2, pre-processing the audio file to be encrypted; S3, generating multiple chaotic sequences by driving the system; S4, encrypting the pre-processed audio file according to the generated chaotic sequence and logistic mapping sequence, and transmitting the encrypted audio file; S5, select an n-dimensional fractional-order chaotic system as the response system; S6, establishing an error system based on the established driving system and response system; S7, design a new fractional-order integral sliding mode controller to achieve synchronization between the drive system and the response system, that is, use the new fractional-order integral sliding mode controller to make the state of the error system 0; S8, after receiving the encrypted audio file, decrypting the encrypted audio file according to the chaotic sequence and logistic mapping sequence generated by the synchronized response system.

2. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 1 is characterized in that: Said S1 comprises: S11, the integrable function of The fractional integral is defined as: ； in, , is the gamma function, ; S12, function The Caputo-type fractional derivative is defined as: ； in, , , ; when hour, ; S13, according to the definition of Caputo-type fractional-order calculus, the model of the m-dimensional fractional-order drive system is: ； in, is the fractional order of the system, represents the state vector of the system, represent the internal uncertainty and external disturbance of the system respectively, is a known continuous nonlinear function.

3. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 1 is characterized in that: The S2 includes: S21, resampling the audio file to be encrypted; S22, performing normalization processing on the resampled audio file; S23, maps the normalized audio file to a 16-bit integer, i.e. scope.

4. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 3 is characterized in that: The S3 includes: S31, intercepting the drive system synchronization time according to the pre-processed audio file size After a certain period of time, multiple groups of chaotic sequences with corresponding dimensions are generated; S32, comparing the length of the preprocessed audio file with the length of the chaotic sequence. If the length of the audio file is greater than the length of the chaotic sequence, the chaotic sequence is repeatedly superimposed to extend the length of the audio file until the length exceeds the length of the audio file, and a portion equal to the length of the audio file is intercepted. S33, if the length of the audio file is less than the length of the chaotic sequence, directly intercept the part with the same length as the audio file to meet the encryption requirements; S34, maps the values ​​in the chaotic sequence to The range is consistent with the audio file.

5. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 4 is characterized in that: The S4 includes: S41, performing multiple XOR operations on the audio file and the chaotic sequence to complete the initial encryption; S42, using a Logistic map to generate a set of sequences, arranging the audio file after the initial encryption in ascending order according to the sequence generated by the Logistic map, performing index scrambling, and performing polarity scrambling according to the median of the sequence generated by the Logistic map; S43, converting the encrypted voice data into .wav format for transmission.

6. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 2 is characterized in that: The response system model is expressed as: ； in, is the fractional order of the system, represents the state vector of the system, represent the internal uncertainty and external disturbance of the system respectively, is a known continuous nonlinear function, is the control input.

7. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 6 is characterized in that: The S6 includes: S61, defines the synchronization error between the states of the driving system and the response system, expressed as: ； in, is a constant matrix with full row rank, which maps the driving system state space to the response system state space; S62, will Synchronous Controller and compensation controller , expressed as: ； ； S63, establish the mathematical model of the error system, expressed as: 。 8. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 7 is characterized in that: The S7 includes: S71, the sliding mode surface of the fractional-order integral sliding mode controller is expressed as: ； in, and is any positive constant, ; ； S72, the new fractional-order integral sliding mode controller is expressed as: ； in, and is any positive constant, ; ； S73, the drive system and the response system will be in a predefined time Synchronization completed.

9. The voice encryption and decryption method based on fractional order chaotic system synchronization according to claim 8, characterized in that: The S8 includes: S81, converting the encrypted audio file into a 16-bit integer; S82, based on the response system, a chaotic sequence with the same length as the audio file is generated and the same number of XOR operations are performed to complete the initial decryption; S83: Generate a set of sequences according to the Logistic map, arrange the audio files after the initial decryption in ascending order according to the sequences generated by the Logistic map, perform inverse index scrambling, and perform inverse polarity scrambling according to the median of the sequences generated by the Logistic map, and restore the decrypted audio files to .wav format.

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