A digital domain double scrambling method and device based on time domain pinhole

Abstract

The application discloses a digital domain double scrambling method and device based on a time domain small hole, and the method comprises the following steps: acquiring a key initial value and bit information to be sent; generating a disturbance sequence by using a new four-wing chaotic system according to the key initial value; sequentially performing OFDM modulation and QAM carrier mapping on the bit information to be sent to obtain a carrier signal; performing carrier scrambling on the carrier signal by using the disturbance sequence to obtain a frequency domain signal; performing inverse Fourier transform on the frequency domain signal to obtain a time domain signal; performing time domain small hole signal inversion on the time domain signal by using the disturbance sequence to obtain a time domain inverted signal; and modulating a telecommunication signal onto light after the time domain inverted signal is converted from digital to analog, thereby completing optical transmission. The double encryption in the digital domain is realized, so that the information has higher security in the transmission process, and the signal transmission performance is not affected.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical transmission communication, and particularly relates to a digital domain double scrambling method and device based on a time domain small hole. BACKGROUND

[0002] With the vigorous development of mobile Internet, mankind has fully entered the big data era, and mobile communication business presents explosive growth, which promotes the rapid growth of global mobile data traffic. The development of mobile communication not only profoundly changes people's way of life, but also becomes an important engine for promoting the development of national economy and improving the level of social informatization. In recent years, with the popularization of the fifth generation mobile communication technology, the Internet traffic has also rapidly increased, and people's demand for larger capacity, faster rate and higher quality communication network technology has become more and more urgent. OFDM technology is a very common technology, and its use is very wide. Due to its high spectral efficiency and noise robustness, it has been widely studied.

[0003] At the same time, due to the openness of the network, security problems cannot be ignored. In the current communication system, in order to ensure the secure transmission of information, quantum encryption and chaotic encryption and other secure encryption methods appear. Since there are problems such as too low key generation rate, non-reproducibility of single photons, and increased cost and complexity of the communication system in quantum encryption, a digital domain chaotic encryption technology based on digital signal processing is selected. Chaotic encryption technology is widely used in various encryption schemes due to its high sensitivity to initial conditions. By combining chaotic technology with OFDM, the confidentiality of data can be effectively protected, thereby improving the overall security of the communication system. At the same time, in OFDM, signal generation and modulation can be performed through digital signal processing, and it is very convenient and fast to use chaotic encryption in this process, so that the chaotic encryption method becomes the only choice for improving information security.

[0004] However, most of the existing chaotic encryption schemes use low-order chaotic systems or single encryption methods. With the continuous development of decryption technology, the original encryption scheme is being eliminated. The chaotic behavior of low-order chaotic systems is relatively single, the dynamic behavior is relatively easy to predict, and the key space is smaller, so it is easier to be cracked. The single encryption method greatly reduces the difficulty of decryption. SUMMARY

[0005] Purpose: In view of at least one of the above technical problems, the application provides a digital domain double scrambling method and device based on a time domain small hole, which uses chaotic mapping to encrypt the transmission information at the physical layer to improve the communication security in the OFDM system, uses the time domain small hole technology to realize the inversion of the waveform, and cooperates with a four-wing chaotic system to generate a disturbance sequence and realize double scrambling of information.

[0006] The technical scheme adopted by the present application is as follows:

[0007] In a first aspect, the present application provides a digital domain double scrambling method based on time domain pinholes, comprising:

[0008] obtaining a key initial value and bit information to be sent;

[0009] generating a disturbance sequence using a four-wing chaotic system according to the key initial value;

[0010] performing OFDM modulation and QAM carrier mapping on the bit information to be sent in sequence to obtain a carrier signal;

[0011] scrambling the carrier signal using the disturbance sequence to obtain a frequency domain signal;

[0012] performing inverse Fourier transform on the frequency domain signal to obtain a time domain signal;

[0013] performing time domain pinhole signal inversion on the time domain signal using the disturbance sequence to obtain a time domain inverted signal;

[0014] modulating the electrical signal onto light after digital-to-analog conversion of the time domain inverted signal to complete optical transmission.

[0015] In a second aspect, the present application provides a digital domain double scrambling device based on time domain pinholes, comprising a processor and a storage medium;

[0016] The storage medium is used to store instructions;

[0017] The processor is used to operate according to the instructions to execute the method according to the first aspect.

[0018] In a third aspect, the present application provides a computer readable storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the method of the first aspect.

[0019] Advantages: The digital domain double scrambling method and device based on time domain pinholes provided by the present application have the following advantages: Different from the traditional chaotic encryption process, the present application generates a disturbance sequence using a four-wing chaotic system to realize scrambling of the carrier, and simultaneously realizes inversion of the time domain signal in cooperation with the time domain pinhole technology, thereby achieving double scrambling in the digital domain. In this process, a high-order four-wing chaotic system is used to generate a scrambling matrix, column permutation is used for scrambling of the carrier to disturb the carrier order, and in the time domain signal inversion, the disturbance sequence is combined with the time domain pinhole to disturb the inverted signal waveform, thereby realizing double encryption in the digital domain. The information has higher security in the transmission process, and the signal transmission performance is not affected. Moreover, no other optical devices are required, so the cost is lower and the security is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a flow chart of a digital domain dual-reset scrambling method based on a time domain pinhole according to an embodiment of the present application;

[0021] Figure 2 Schematic diagram of phase trajectory in two dimensions uz, yz, yu, zx according to one embodiment of the present application;

[0022] Figure 3 2 is a schematic diagram of column replacement according to an embodiment of the present application;

[0023] Figure 4 Schematic diagram of the spatial pinhole imaging principle according to one embodiment of the present application;

[0024] Figure 5 Schematic diagram of a time domain signal after passing through a time domain aperture according to an embodiment of the present application;

[0025] Figure 6 FIG. 4 is a schematic diagram of a time-domain pinhole signal waveform inversion process according to an embodiment of the present application. DETAILED DESCRIPTION

[0026] The present application will be further described below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application.

[0027] In the description of this application, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0028] Throughout the description of this application, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0029] The term "and / or" simply describes a relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, or B exists alone. Additionally, the character " / " generally indicates an "or" relationship between the related objects.

[0030] Example 1: This example provides a digital domain dual reset scrambling method based on a time domain pinhole, such as Figure 1 Shown, including:

[0031] S1. Obtain the initial value of the key and the bit information to be sent;

[0032] S2, generating a disturbance sequence using a four-wing chaotic system according to the initial value of the key;

[0033] S3, performing OFDM modulation and QAM carrier mapping on the bit information to be transmitted in sequence to obtain a carrier signal;

[0034] S4. Perform carrier scrambling on the carrier signal using the perturbation sequence to obtain a frequency domain signal;

[0035] S5. Performing an inverse Fourier transform on the frequency domain signal to obtain a time domain signal;

[0036] S6. Performing a time-domain pinhole signal inversion on the time-domain signal using the perturbation sequence to obtain a time-domain inversion signal;

[0037] S7. After the time-domain inverted signal is subjected to digital-to-analog conversion, the electrical signal is modulated onto light to complete the optical transmission.

[0038] After the inverse Fourier transform, the frequency domain signal is converted to the time domain signal. Before the time domain pinhole scrambling step, the carrier must first be scrambled to perform the first level of encryption. This process is described in detail below.

[0039] Chaotic systems are characterized by unpredictability, high randomness, and sensitivity to initial values. Therefore, using chaotic systems for encryption is a very promising approach. Low-dimensional (three-dimensional and below) chaotic systems generally have few and relatively low Lyapunov exponents, which can lead to overly simple dynamical behavior. This can lead to drawbacks in information security, such as a small key space and unstable periodic windows. Therefore, this patent selects a four-wing chaotic system with more complex dynamical behavior and greater security to generate a perturbation sequence to achieve carrier scrambling.

[0040] In some embodiments, in step S2, the model of the four-wing chaotic system is expressed as:

[0041] ,

[0042] where x, y, z, u are four state variables, t represents time, a, b, c are control parameters, and a, c are positive real numbers, b is a real number, yz and y 2 are two quadratic nonlinear terms;

[0043] A perturbation sequence (Xn, Yn, Zn, Un) is generated from the four-wing chaotic system according to a key initial value.

[0044] In some embodiments, (a, b, c) = (0.6, 0.1, 20) and the key initial value (x0, y0, z0, u0) = (0.01, 0.01, 0, 0). At this time, the chaotic system mapping phase diagram is as shown in Figure 2 .

[0045] In the encryption part, column permutation encryption in classical cryptography is adopted. Column permutation encryption is an encryption process that is usually used to rearrange columns in a data table, matrix or array to improve the security of data.

[0046] In some embodiments, S4, using the perturbation sequence, performs carrier scrambling on the carrier signal to obtain a frequency domain signal, including:

[0047] The perturbation sequence {Xn} is preprocessed to obtain a permutation matrix for column permutation, forming a column permutation order;

[0048]

[0049] where Mat{} represents taking 0 for non-integer elements in the matrix, mod() represents taking the remainder, M is the total number of subcarriers in the carrier signal; is the mth value in {Xn};

[0050] The carrier signal is split into several columns, and each column of the carrier signal is rearranged using the column permutation order to obtain a scrambled carrier signal, i.e. a frequency domain signal, as shown in Figure 3 .

[0051] Further, the frequency domain signal is expressed as:

[0052]

[0053] where, represents the ith subcarrier, is a natural constant, represents the imaginary unit, represents the frequency of the ith subcarrier, Time is represented.

[0054] After the carrier scrambling process, the information needs to be encrypted again using the time domain pinhole signal inversion technology. Next, this process is described in detail.

[0055] The principle of spatial pinhole imaging is shown in FIG. 1. Figure 4 The object I l After a spatial distance d l transmission through the pinhole, and then through a distance d o transmission imaging to obtain I o .

[0056] Mapping this concept to the time domain pinhole can be embodied as the inversion of information, which realizes the encryption of the signal. For example: in the frequency domain, a string of "1101" information, after passing through the pinhole, becomes "1011", and in the time domain, it is embodied as the inversion of the time domain waveform. The "pinhole" referred to here is not a physical hole, but a novel concept derived from the concept of spatial pinhole imaging. The "inversion" of spatial pinhole imaging is given to the signal processing module, so that the signal is inverted when it passes through.

[0057] If only the entire waveform is inverted, the concept of time domain pinhole is meaningless, so this patent selects to use the disturbance sequence generated by the four-wing chaotic system to determine the position of the time domain pinhole in the waveform. Due to the unpredictability of the chaotic system, the position of the time domain pinhole in the waveform also becomes fixed, and at this time, the waveform inversion can realize signal disturbance and obtain encryption effect, thereby improving information security. When decryption is needed, only the opposite operation is needed.

[0058] In some embodiments, S6, using the disturbance sequence to perform time domain pinhole signal inversion on the time domain signal to obtain a time domain inverted signal, comprises:

[0059] Using the disturbance sequence {Yn} to determine the position of the time domain pinhole;

[0060] Symmetrically inverting the waveform of the time domain signal with the time domain pinhole as the center to obtain the time domain inverted signal.

[0061] At the receiving end, to decrypt the data, the same four-wing chaotic system mapping parameters, keys, time domain pinholes and column arrangement order are needed to restore the column order of the original data. First, the signal is subjected to FFT processing to obtain the OFDM signal in the frequency domain, then a waveform inversion is performed through the time domain pinhole, and then the same operation is performed on the column permutation through the key. After all the carriers are returned to their original positions, the symbol information on the data carrier is correctly extracted, and then demapping is performed to restore the initial bit information stream.

[0062] Embodiment 2: Based on embodiment 1, this embodiment provides a time-domain small-hole-based digital-domain double scrambling device, comprising a processor and a storage medium;

[0063] The storage medium is configured to store instructions.

[0064] The processor is configured to operate according to the instructions to perform the method according to embodiment 1.

[0065] Embodiment 3: Based on embodiment 1, this embodiment provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the method according to embodiment 1.

[0066] Embodiment 4: Based on embodiment 1, this embodiment provides a computer device, comprising a memory and a processor, the memory storing a computer program, the processor implementing the method according to embodiment 1 when executing the computer program.

[0067] Embodiment 5: Based on embodiment 1, this embodiment provides a computer program product, comprising a computer program, the computer program being executed by a processor to implement the method according to embodiment 1.

[0068] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0069] The present application is described with reference to flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing devices to produce a machine, so that the instructions executed by the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 An apparatus for performing each flow or multiple flows and / or blocks Figure 1 An apparatus for performing each flow or multiple flows and / or blocks

[0070] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the flow Figure 1 The flow or flows and / or blocks Figure 1 The function specified in the flow or flows and / or block or blocks.

[0071] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the flow Figure 1 The flow or flows and / or blocks Figure 1 The function specified in the flow or flows and / or block or blocks.

[0072] The above only is the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A time-domain hole-based digital-domain double scrambling method, characterized in that, The method comprises: obtaining a key initial value and bit information to be sent; generating a disturbance sequence by using a four-wing chaotic system according to the key initial value; performing OFDM modulation and QAM carrier mapping on the bit information to be sent in sequence to obtain a carrier signal; performing carrier scrambling on the carrier signal by using the disturbance sequence to obtain a frequency domain signal; performing inverse Fourier transform on the frequency domain signal to obtain a time domain signal; performing time domain pinhole signal inversion on the time domain signal by using the disturbance sequence to obtain a time domain inverted signal; after digital-to-analog conversion, the time domain inverted signal is modulated onto light to complete optical transmission. The model of the four-wing chaotic system is represented as: where x, y, z, u are four state variables, t represents time, a, b, c are control parameters, and a, c are positive real numbers, b is a real number, yz and y 2 are two quadratic nonlinear terms; generating a disturbance sequence (Xn, Yn, Zn, Un) by using the four-wing chaotic system according to the key initial value; performing time domain pinhole signal inversion on the time domain signal by using the disturbance sequence to obtain a time domain inverted signal, which comprises: determining the position of the time domain pinhole by using the disturbance sequence {Yn}; and performing symmetric inversion on the waveform of the time domain signal with the time domain pinhole as the center to obtain the time domain inverted signal.

2. The method of claim 1, wherein, a is 0.6, b is 0.1, and c is 20.

3. The method of claim 1, wherein, The key initial value (x0, y0, z0, u0) is (0.01, 0.01, 0, 0).

4. The method of claim 1, wherein, performing carrier scrambling on the carrier signal by using the disturbance sequence to obtain a frequency domain signal, which comprises: The disturbance sequence {Xn} is preprocessed to obtain a set of permutation matrices X for column permutation m , forming a column permutation order X m = Mat{mod([x1,x m ,...,x M ],1)[mod([x1,x m ,...,x M ],1)]'},m = 1,2,...,M, where Mat{} means taking 0 for non-integer elements in the matrix, mod() means taking remainder, M is the total number of subcarriers in the carrier signal; x m is the mth value in {Xn}. splitting the carrier signal into several columns, and rearranging each column of the carrier signal by using the column permutation sequence to obtain a scrambled carrier signal, i.e., a frequency domain signal.

5. A time-domain aperture-based digital-domain double-scrambling device, characterized by, The method comprises a processor and a storage medium. The storage medium is used to store instructions. The processor is used to operate according to the instructions to perform the method according to any one of claims 1 to 4.

6. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program, when executed by the processor, implements the method according to any one of claims 1 to 4. 7.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-6 when the computer program is executed by the processor. The processor, when executing the computer program, implements the method according to any one of claims 1 to 4.

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