An Audio Data Encryption Method Based on Chaotic Sequences and Cosine Mapping

Abstract

This invention discloses an audio data encryption method based on chaotic sequences and cosine mapping, specifically including the following steps: S1: Obtain the audio data to be encrypted and split it into audio sequences; S2: Scramble the audio sequences to obtain the first sequence to be encrypted; S3: Construct a chaotic system to generate a chaotic sequence, and map and encrypt the chaotic sequence to obtain a key sequence; S4: Perform an XOR operation on the first sequence to be encrypted and the key sequence to output the encrypted sequence.

Description

Technical Field

[0001] This invention relates to the field of data security technology, and in particular to an audio data encryption method based on chaotic sequences and cosine mapping. Background Technology

[0002] Existing audio encryption methods mainly focus on complex encryption algorithms, while ignoring the consumption of computing resources and failing to consider the advantages of computer bit operations. This makes the audio encryption process complex and even makes it difficult to guarantee the real-time performance of audio transmission.

[0003] Taking patent application number 202010502531.6, "A Bit-Level Audio Encryption Method Based on Chaos," as an example, this invention utilizes a chaotic system to generate chaotic sequences, then scrambles the audio data and performs an XOR operation on one of the chaotic sequences to complete audio encryption. This scheme does not fully utilize the random characteristics of chaotic sequences; instead, it maps the amplitude sorting of the chaotic sequences to the scrambling of the audio sequences, and finally uses only one variable sequence from the chaotic sequence to complete the audio encryption. This involves sorting the sequences, which is computationally intensive, resource-intensive, and cannot guarantee the real-time performance of audio transmission.

[0004] Taking the patent application No. 202010502514.2, "Multi-Audio Encryption Method Based on Chaos and Zigzag Transform," as an example, this invention utilizes a chaotic system to generate chaotic sequences, then uses a two-dimensional Zigzag transform to scramble the audio data, and finally performs an XOR operation on one of the chaotic sequences to complete the audio encryption. Although this scheme combines two-dimensional Zigzag transform and chaotic sequences, it does not fully utilize the random characteristics of chaotic sequences, using only one variable sequence of the chaotic sequence to complete the audio encryption. Furthermore, it involves sorting operations on the sequences, resulting in a large computational load, high resource consumption, and an inability to guarantee the real-time performance of audio transmission.

[0005] Taking the patent application No. 202210514672.9, "Audio Encryption Method Based on DNA Convolution," as an example, this invention combines the randomness of DNA convolution kernels and chaotic sequences, using DNA convolution operations to achieve audio encryption. However, according to the patent description, for an audio sequence of length 73120, it will be converted into a 73120 x 8 DNA matrix, while the DNA convolution kernel is 8 x 8. Therefore, the complexity of DNA convolution operations is extremely high, and the real-time performance of audio transmission cannot be guaranteed. Summary of the Invention

[0006] To address the issue of low security in existing audio data technologies, this invention proposes an audio data encryption method based on chaotic sequences and cosine mapping. By using chaotic sequences to encrypt audio data, a higher level of privacy protection can be provided, ensuring that sensitive audio information cannot be accessed or stolen by unauthorized individuals.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] An audio data encryption method based on chaotic sequences and cosine mapping specifically includes the following steps:

[0009] S1: Obtain the audio data to be encrypted and split it into audio sequences;

[0010] S2: Scramble the audio sequence to obtain the first sequence to be encrypted;

[0011] S3: Construct a chaotic system to generate a chaotic sequence, and then map and encrypt the chaotic sequence to obtain a key sequence;

[0012] S4: Combine the first sequence to be encrypted and the key sequence to output the encrypted sequence.

[0013] Preferably, S1 includes:

[0014] S1-1: Obtain the audio data to be encrypted;

[0015] S1-2: Split the audio data to be encrypted into audio sequences.

[0016] Preferably, S1-2 specifically comprises:

[0017] The audio data to be encrypted includes n audio samples;

[0018] Each audio sample is quantized in 16 bits, and then each sample is split into high 8 bits and low 8 bits to obtain split samples;

[0019] The audio sequence S is obtained by splitting the n sample sets.

[0020] Preferably, S2 includes:

[0021] S2-1: Calculate the corresponding inverse element of the audio sequence;

[0022] S2-2: Perform an affine transformation on the obtained inverse element to obtain the transformation parameters;

[0023] S2-3: Use the transformation parameters as output bytes to form entries in the S-box, and obtain the first encrypted sequence D.

[0024] Preferably, in S2-2, the formula for the affine transformation is:

[0025] w=A·θ+b(1)

[0026] In formula (1), w represents the transformation parameter; A is a fixed 8×8 linear transformation matrix; b is a constant vector; and θ represents the inverse element.

[0027] Preferably, S3 includes:

[0028] S3-1: Constructing a chaotic system;

[0029] S3-2: Generate chaotic sequences based on the constructed chaotic system;

[0030] S3-3: Mapping a chaotic sequence to a preset interval using cosine mapping to obtain a mapped sequence;

[0031] S3-4: Quantize the mapping sequence into 16 bits to obtain the key sequence G.

[0032] Preferably, in S3-1, the chaotic system is:

[0033]

[0034] In formula (2), x, y, and z represent the state variables of the chaotic system.

[0035] Preferably, S3-2 includes:

[0036] S3-2-1: Pre-iterate the chaotic system N1 times;

[0037] S3-2-2: Iterate the chaotic system N2 times to generate a new state value A = {A}. x A y A z},in,

[0038] A x = {x1, x2, ..., x k}, A y = {y1,y2,...,y k}, A z = {z1, z2, ..., z k}, 0 <k≤P;x k y k ,

[0039] z k Let P represent the state values ​​of each variable in the k-th iteration of the chaotic system, and let P represent the length of the sequence to be encrypted divided by 3.

[0040] S3-2-3: Based on the changes in the value of state variable A, adjust the order of the state variables to generate a chaotic sequence C = {C1, C2, ..., C}. k}

[0041] Preferably, in S3-3, the objective function of the cosine mapping is as follows:

[0042] q=cos(T·ε+b) (3)

[0043] In formula (3), q represents the mapping sequence value; T controls the frequency of the cosine function; b controls the phase shift of the cosine function; and ε represents the input value of the chaotic sequence.

[0044] Preferably, S4 includes:

[0045] First, perform an XOR operation between the first encryption sequence D and the high 8 bits and low 8 bits of the key sequence G to obtain the first calculation result and the second calculation result:

[0046] D n = {d1, d2, ..., d m / 2}, G n = {g1, g2, ..., g m / 2} (4)

[0047] In formula (4), D n Indicates the first calculation result; d m / 2 D represents the first encrypted sequence. n binary bits; G n Indicates the second calculation result; g m / 2 Represents the key sequence G in binary bits;

[0048] Then, the first calculation result is encrypted using an XOR operation:

[0049]

[0050] In formula (5), E n G represents the encryption result. kH G represents the high m / 2 bit subsequence of the chaotic key sequence G; kL The lower m / 2 subsequence of the chaotic key sequence G is shown. This represents the XOR operation.

[0051] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects compared with the prior art:

[0052] This invention combines chaotic sequences and cosine mapping to enhance the randomness and nonlinearity of the encrypted sequence, avoiding the problems of high computational complexity and high resource consumption in existing technologies, while achieving simple, efficient and low-resource-consumption audio encryption.

[0053] Real-time optimization: By simplifying algorithm complexity and reducing computational resource consumption, the real-time performance of audio encryption and decryption is improved, making it suitable for rapid processing needs during transmission.

[0054] High security: By utilizing an improved Lorenz chaotic system, key sequences with high randomness and resistance to linear attacks are generated, enhancing the protection of sensitive audio data.

[0055] Wide range of applications: The technical solution is applicable to multiple fields such as communication technology, network audio streaming, military defense, and healthcare, covering a wide range of scenarios from privacy protection to commercial applications.

[0056] Low-cost implementation: The encryption algorithm is implemented in software, eliminating the need for additional hardware, reducing implementation costs, and making it suitable for widespread adoption. Attached image description:

[0057] Figure 1 This is a schematic diagram of an audio data encryption method based on chaotic sequences and cosine mapping according to an exemplary embodiment of the present invention.

[0058] Figure 2 This is a schematic diagram of audio data splitting according to an exemplary embodiment of the present invention. Detailed Implementation

[0059] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0060] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0061] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0062] like Figure 1 As shown, this invention provides an audio data encryption method based on chaotic sequences and cosine mapping, specifically including the following steps:

[0063] S1: Obtain the audio data to be encrypted and split it into audio sequences.

[0064] S1-1: Obtain the audio data to be encrypted.

[0065] In this embodiment, audio data is presented in frames, typically with 10ms samples per frame, though this can be customized. A frame is usually no longer than 20ms. For example, with a 16kHz sampling rate, 10ms represents 160 samples.

[0066] S1-2: Split the audio data to be encrypted into audio sequences.

[0067] like Figure 2 As shown, each audio sample is quantized in 16 bits. To facilitate subsequent processing, each sample is split into high 8 bits and low 8 bits to obtain the audio sequence S.

[0068] The audio data to be encrypted includes N samples. The original audio samples are quantized in 16-bit format. After being split into two 8-bit sequences, the sequence length becomes 2N. Therefore, the length D of the first encrypted sequence after the calculation should be 2N.

[0069] In this embodiment, each sample has the same structure, so the first sample is used as an example for explanation. The first sample is quantized to 16 bits as {15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0}. Then, the first sample is split into the high 8 bits {15,14,13,12,11,10,9,8} and the low 8 bits {7,6,5,4,3,2,1,0}, thus forming the first split sample.

[0070] By analogy, we can obtain the second split sample, the Nth split sample, and the audio sequence S can be obtained by collecting all the split samples.

[0071] S2: The audio sequence is scrambled based on the AES encryption algorithm to obtain the first sequence to be encrypted.

[0072] S2-1: Finite field GF(2) based on AES encryption algorithm 8 The inverse element is calculated in the audio sequence.

[0073] For each input byte (referring to the audio sequence output by S1), first find its value in the finite field GF(2). 8 The inverse element in the expression is used to construct the S-box. An inverse element is an element x such that, for a given element x, there exists an inverse element x. -1 This makes their product equal to 1, i.e., x·x -1 =1.

[0074] In this embodiment, the S-box (Substitution Box) is an important component of the AES algorithm. It increases the complexity of the cipher by applying a non-linear substitution operation to each data block (byte), making the encryption more difficult to crack through simple linear analysis.

[0075] The AES encryption process involves several steps, one of which is scrambling using an S-box. In the AES algorithm, the S-box performs byte substitution during encryption, replacing each input byte (a number between 0 and 255) with a new byte to form a new data block.

[0076] 1. Structure of the S-box

[0077] AES uses a fixed S-box for byte substitution operations. This S-box is a non-linear substitution table that maps each byte (8 bits, 0–255). The design of the S-box is based on mathematically irreversible functions; specifically, it uses the inverse element operation over GF(2^8) (a finite field) and an affine transformation.

[0078] The construction process of the S-box includes the following steps:

[0079] Inverse: First, the input value of the AES S-box is regarded as an element over GF(2^8), and the inverse of that element is calculated first (in a finite field).

[0080] Affine transformation: Then, the inverse element is transformed by an affine transformation (a linear transformation plus a constant) to obtain the final S-box output.

[0081] 2. Construction process of S-box

[0082] Suppose we want to encrypt a byte x (with a value ranging from 0 to 255). First:

[0083] Consider x as an element in the finite field GF(2^8).

[0084] By performing the inverse operation on x, we obtain its inverse element in GF(2^8).

[0085] Perform an affine transformation on the obtained inverse element, and obtain the output of the S-box using a predefined matrix and constants.

[0086] The design of the S-box creates a strong non-linear relationship between its output and input, which ensures the security of AES.

[0087] 3. S-box scrambling in AES

[0088] In the AES encryption process, S-box scrambling occurs during the SubBytes step. This step performs the following operations on each byte:

[0089] SubBytes: For each byte x, find the corresponding value S(x) in the S-box and replace the original byte with the value at the corresponding position in the S-box. The purpose of this step is to break the linear structure of the input bytes, making the ciphertext more random.

[0090] For example, if the input block contains the byte 0x32, it might be replaced with 0x87 after an S-box lookup. This byte substitution is irreversible, thus increasing the strength of the cipher.

[0091] 4. Application of S-box in AES encryption process

[0092] In AES encryption, S-box scrambling is achieved through multiple rounds of SubBytes steps. In each round, the input data (data block) is broken down into multiple bytes, and each byte is replaced using an S-box. The specific process is as follows:

[0093] AddRoundKey: Performs an XOR operation between the input data and the round key.

[0094] SubBytes: Apply S-box substitution (scrambling) to each byte.

[0095] ShiftRows: Shifts data rows cyclically.

[0096] MixColumns (only in all rounds except the last one): Performs matrix transformations on data columns to increase the data's versatility.

[0097] AddRoundKey: Performs an XOR operation with the round key again.

[0098] These steps will be repeated multiple times until the encrypted ciphertext is finally obtained.

[0099] In this embodiment, the core design principle of the S-box is to enhance the non-linearity of encryption. In the AES algorithm, the role of S-box scrambling is as follows:

[0100] Increasing cryptographic complexity: By replacing one byte of input with another, the S-box scrambles the structure of the data, making the relationship between the output and input highly complex. Without a suitable key, the output value cannot be predicted.

[0101] Enhanced resistance to attacks: The nonlinear properties of S-boxes are crucial for resisting linear attacks, differential attacks, and other mathematical attacks.

[0102] Increased encryption strength: The S-box provides irreversible transformations, making it difficult to reverse-engineer the original data or key even if some bytes in the encryption process are analyzed.

[0103] AES's S-box design prioritizes security, employing numerous mathematical techniques to ensure robust resistance to attacks. The S-box design enhances security in the following ways:

[0104] Unpredictability: The S-box is carefully designed to ensure that the output of each byte substitution operation is unpredictable, reducing direct inference from the original data.

[0105] Resistance to differential attacks: A differential attack is an attack method that cracks the key by analyzing the differences between the input and output during the encryption process. The AES S-box is designed to avoid patterns that are easily exploited by differential attacks, thus improving its resistance to such attacks.

[0106] Resistance to linear attacks: Linear attacks rely on finding a linear relationship between the input and output. AES's S-box makes such attacks very difficult through its highly nonlinear substitution behavior.

[0107] In this embodiment, calculating the inverse element of the input byte requires the use of the finite field GF(2). 8 The multiplication rule is achieved by solving a specific polynomial (this is existing technology, so it will not be elaborated here).

[0108] In this embodiment, within the finite field GF(2) 8 In S-box construction, the zero element 0x00 has no inverse element. Therefore, the zero element is specially handled during the construction of the S-box and is usually mapped to a fixed value of 0x63 to avoid errors.

[0109] S2-2: Perform an affine transformation on the obtained inverse element to obtain the transformation parameters.

[0110] In this embodiment, a fixed linear affine transformation is used to further scramble the structure of the inverse element. The formula for the affine transformation is:

[0111] w=A·θ+b(1)

[0112] In formula (1), w represents the transformation parameter; A is a fixed 8×8 linear transformation matrix; b is a constant vector; and θ represents the inverse element. The purpose of affine transformation is to enhance the unpredictability and resistance to linear attacks of the S-box, making the output of the S-box difficult to derive from simple linear relationships.

[0113] S2-3: The transformation parameters are used as new output bytes to form entries in the S-box.

[0114] In this embodiment, after the above steps (S2-1, S2-2, S2-3), a corresponding output byte is generated for each input byte (0 to 255). The entire S-box is a lookup table of size 256, containing the mapping from input bytes to output bytes. This achieves the scrambling operation of the audio sequence, which is also the initial encryption of the audio sequence, resulting in the first encrypted sequence D.

[0115] S3: Construct a chaotic system to generate a chaotic sequence, and then map and encrypt the chaotic sequence to obtain a key sequence.

[0116] S3-1: Constructing a chaotic system.

[0117] Chaos is a deterministic, quasi-random process that occurs in nonlinear dynamic systems. This process is neither periodic nor convergent, and it is sensitive to initial values. Its behavior is characterized by uncertainty, non-repeatability, and unpredictability.

[0118] This invention constructs a new three-dimensional chaotic system based on the three-dimensional improved Lorenz chaotic system:

[0119]

[0120] In formula (2), x, y, and z represent the state variables of the chaotic system. The Lyapunov exponents can be used to determine whether the system has chaotic characteristics. The Lyapunov exponents are an important indicator for quantifying the sensitivity of a system to initial conditions. A positive Lyapunov exponent indicates that the system has an exponential sensitivity to small changes in initial conditions. This behavior is a typical characteristic of chaotic systems.

[0121] For constructing a chaotic system, numerical analysis yielded a Lyapunov exponent of (2.1693, 0, -20.1667), indicating that the constructed chaotic system possesses chaotic characteristics. This invention uses this novel chaotic system as a basis to generate chaotic sequences.

[0122] S3-2: Generate chaotic sequences based on the constructed chaotic system.

[0123] Due to the high randomness and complexity of chaotic systems, specific quantization algorithms transform chaotic sequences into the desired form, enhancing the security of encryption algorithms. The specific operation is as follows:

[0124] S3-2-1: Iterate the chaotic system N1 times to eliminate the transient effects of the chaotic system entering a chaotic state.

[0125] S3-2-2: Iterate the chaotic system N2 times to generate a new set of state values ​​A = {Ax A y A z}, where A x ={x1,x2,...,x k}, A y ={y1,y2,...,y k}, A z ={z1,z2,...,z k}, 0 <k≤P;x k y k z k Let P represent the state values ​​of each variable in the k-th iteration of the chaotic system, and let P represent the length of the sequence to be encrypted divided by 3.

[0126] S3-2-3: Based on the changes in the value of state variable A, adjust the order of the state variables to generate a chaotic sequence C = {C1, C2, ..., C...} k},C k This represents the chaotic result of the k-th iteration of the chaotic system. The mapping relationship between the sorting rules of the chaotic sequence C and the state variable A is shown in Table 1.

[0127] Table 1. Mapping relationship between the sorting rules of the chaotic sequence C and the state variable A.

[0128]

[0129] S3-3: Map the chaotic sequence to a preset interval to obtain a mapped sequence.

[0130] Since the chaotic sequence generated by S3-2 has a large value range, it cannot be effectively controlled within the range of [0,1], which will adversely affect the next step of chaotic encryption (in XOR operation, the input value range is best between [0,1], so as to avoid the scaling problem of the input value detection). Therefore, this step maps the input value of the chaotic sequence to the specified interval [0,1] through the cosine mapping function, which can further improve the nonlinearity of the chaotic sequence.

[0131] The objective function for cosine mapping is as follows:

[0132] q=cos(T·ε+b) (3)

[0133] In formula (3), q represents the mapped sequence value; T controls the frequency of the cosine function, and b controls the phase shift of the cosine function. By adjusting the parameter T, the periodicity and complexity of the generated sequence can be changed. A larger T leads to faster changes, resulting in a shorter period of the generated random number sequence, while a smaller T leads to slower changes and a longer period. Typically, T is set to 2 or 3. The parameter b determines the starting point of the mapping, and is usually set to π / 2. ε represents the input value of the chaotic sequence.

[0134] S3-4: Quantize the mapping sequence into 16 bits to obtain the key sequence G.

[0135] S4: To demonstrate the simplicity and non-linear advantages of chaotic key implementation, and to fully leverage the advantages of ciphertext interleaving and diffusion technology in audio encryption, thereby enhancing its resistance to illegal attacks, this invention employs the XOR operation method for audio encryption. Its characteristics include applicability to audio signal encryption, non-linear ciphertext, ease of implementation, and improved ciphertext diffusion speed.

[0136] XORing the first encryption sequence D with the high 8 bits and low 8 bits of the key sequence G respectively yields the first calculation result and the second calculation result:

[0137] D n = {d1, d2, ..., d m / 2}, G n = {g1, g2, ..., g m / 2} (4)

[0138] In formula (4), D n This represents the first calculation result, where n ranges from [1, 2N]; d m / 2 D represents the first encrypted sequence. n binary bits; G n Indicates the second calculation result; g m / 2 The key sequence G represents binary bits; m = 16;

[0139] For example, D n If it is 8 bits, it is represented as {d1, d2, ..., d8}, where d1, d2, ..., d8 take the values ​​of 0 or 1, because the operation of equation (5) is a bitwise XOR operation, which is used here for the sake of convenience.

[0140] Then, the first calculation result is encrypted using an XOR operation to obtain the encrypted result. The encrypted sequence is obtained by concatenating the various encrypted results.

[0141]

[0142] In formula (5), E n G represents the encryption result. kH G represents the high m / 2 bit subsequence of the chaotic key sequence G; kL The lower m / 2 subsequence of the chaotic key sequence G is shown. This represents the XOR operation.

[0143] The present invention has at least the following advantages:

[0144] Audio privacy protection: By using chaotic sequences to encrypt audio data, a higher level of privacy protection can be provided to ensure that sensitive audio information is not accessed or stolen by unauthorized persons;

[0145] Secure communication: In audio communication, such as telephone calls or audio chat, chaotic sequence encryption can prevent eavesdroppers from listening to the content of the communication, thereby protecting the confidentiality of the communication;

[0146] Preventing audio data leakage: Chaotic sequence encryption can help prevent audio data from being stolen by malicious visitors or hackers during transmission or storage, thereby protecting the confidentiality of audio content.

[0147] In protecting the privacy of critical robot data, audio data encryption methods based on chaotic sequences and cosine mapping can effectively safeguard user privacy. This method not only ensures the efficiency and real-time nature of the encryption process but also effectively prevents unauthorized access from eavesdropping on or tampering with sensitive voice commands, ensuring data security and integrity.

[0148] In defense and military communications, military command centers need to coordinate and communicate with various units and personnel deployed in critical military operations. During these communications, highly classified and time-sensitive information, such as troop movements, mission plans, and strategic orders, must be securely exchanged. To ensure maximum security for these communications, the military employs audio encryption based on chaotic sequence technology.

[0149] In the multimedia playback field, music streaming services provide users with a platform for streaming and sharing music. The service offers an advanced subscription tier, allowing users access to a vast library of high-quality audio tracks. To protect the integrity of audio content, ensure artist royalties, and safeguard user privacy, the streaming service employs a patented technology based on chaotic sequences for audio encryption.

[0150] This invention can also be used in the following technical fields:

[0151] Communication technology: This technology can be used to encrypt telephone calls, audio chats and other forms of communication to ensure the confidentiality of communication content. It is applicable to mobile phones, VoIP systems and communication devices.

[0152] Network audio streaming: Used in fields such as online music, video conferencing, and streaming media services to protect audio content from unauthorized access;

[0153] Military and Defense: In the field of military communications and intelligence, protecting the security of sensitive audio information is of paramount importance, and this technology can be applied to military communication equipment and intelligence transmission;

[0154] Healthcare: Used to encrypt audio data in medical records to ensure patient privacy, especially in the fields of telemedicine and electronic health records;

[0155] Law and Law Enforcement: Protection of audio evidence to ensure the integrity and security of audio evidence used in court;

[0156] Enterprise and Commerce: In the business sector, it can be used to protect the privacy of sensitive business meetings and telephone calls, as well as to encrypt audio conferencing and training content;

[0157] Education: Used to encrypt audio course content on online education platforms to ensure the protection of intellectual property rights and educational resources.

[0158] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes can be made in form and detail without departing from the spirit and scope of the present invention.

Claims

1. An audio data encryption method based on chaotic sequence and cosine mapping, characterized in that, Specifically comprising the following steps: S1: obtaining audio data to be encrypted, and splitting into an audio sequence; S2: performing sequence scrambling on the audio sequence to obtain a first sequence to be encrypted; S3: constructing a chaotic system to generate a chaotic sequence, and performing mapping encryption on the chaotic sequence to obtain a key sequence; S4: combining the first sequence to be encrypted and the key sequence to output an encrypted sequence; The S2 comprises: S2-1: calculating the audio sequence to obtain a corresponding inverse element; S2-2: performing affine transformation on the obtained inverse element to obtain a transformation parameter; S2-3: taking the transformation parameter as an output byte to form an entry in an S-box, and obtaining a first encrypted sequence D; The S3 comprises: S3-1: constructing a chaotic system; S3-2: generating a chaotic sequence based on the constructed chaotic system; S3-3: mapping the chaotic sequence to a preset interval by cosine mapping to obtain a mapping sequence; S3-4: quantizing the mapping sequence by 16 bits to obtain a key sequence G; In the S3-3, the objective function of the cosine mapping is as follows: , In Equation (3), q represents a mapped sequence value; T is a frequency that controls the cosine function, and b is a phase offset that controls the cosine function. An input value representing a chaotic sequence.

2. The audio data encryption method based on chaotic sequence and cosine mapping according to claim 1, characterized in that, The S1 comprises: S1-1: obtaining audio data to be encrypted; S1-2: splitting the audio data to be encrypted into an audio sequence.

3. The audio data encryption method based on chaotic sequence and cosine mapping according to claim 2, characterized in that, The S1-2 specifically comprises: The audio data to be encrypted comprises n audio samples; Quantizing each audio sample by 16 bits, and then splitting each sample into high 8 bits and low 8 bits to obtain split samples; Collecting the n split samples to obtain the audio sequence S.

4. The audio data encryption method based on chaotic sequence and cosine mapping as claimed in claim 1, wherein, In the S2-2, the formula of the affine transformation is: , In equation (1), denotes the transformation parameters; is a fixed linear transformation matrix; is a constant vector, denotes the inverse element.

5. The audio data encryption method based on chaotic sequence and cosine mapping as claimed in claim 1, wherein, In the S3-1, the chaotic system is: , In formula (2), x, y, and z represent state variables of the chaotic system.

6. The audio data encryption method based on chaotic sequence and cosine mapping as claimed in claim 1, wherein, The S3-2 comprises: S3-2-1: Pre-iteration of chaotic system seconds; S3-2-2: iterate the chaotic system again , generate a new state value wherein, , , , , , , , denotes the state value of each variable of the chaotic system at the kth iteration, denotes the length of the sequence to be encrypted divided by 3; S3-2-3: According to the numerical change of the state variable A, adjust the order of the state variable to generate a chaotic sequence .

7. The audio data encryption method based on chaotic sequence and cosine mapping as claimed in claim 1, wherein, The S4 comprises: First, the first encryption sequence D is XORed with the high 8 bits and the low 8 bits of the key sequence G to obtain a first calculation result and a second calculation result: , In equation (4), denotes the first calculation result; denotes the first encrypted sequence of binary bit positions; denotes the second calculation result; denotes the binary bit positions of the key sequence G; Then the first calculation result is audio encrypted based on XOR operation: , In Equation (5), represents an encryption result, represents a high m / 2-bit sub-sequence of the chaotic key sequence G; represents a low m / 2-bit sub-sequence of the chaotic key sequence G; represents an XOR operation.

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