A high-precision ghost diffraction encryption method for dynamic targets

Abstract

The present invention proposes a high-precision ghost diffraction encryption method for dynamic targets. The method comprises: using a Michelson interferometer to observe the number of interference fringes moving on an object and performing phase calculations to obtain a set of observed phase change values; using a conversion function to transform the set of observed phase change values to obtain a first-level ciphertext; using the conversion function as a first-level key; constructing a ghost diffraction optical path based on optical elements and the first-level ciphertext; and performing ghost diffraction operations on the first-level ciphertext and four reference quantities to obtain second-level ciphertext and second-level keys, respectively. The present invention introduces ghost diffraction technology into the encryption process. Ghost diffraction uses the statistical correlation characteristics of the light field for imaging. Even when part of the optical path is blocked or interfered with by noise, the image can still be restored through the statistical correlation characteristics, effectively enhancing the anti-interference ability of the encryption method proposed by the present invention.

Description

Technical Field

[0001] The present invention relates to the technical field of optical image encryption, and in particular to a high-precision ghost diffraction encryption method for dynamic targets. Background Art

[0002] The phenomenon of ghost diffraction can be traced back to the mid-twentieth century, when research on the properties of quantum entanglement began. Due to its non-local nature, ghost diffraction technology offers a new avenue for achieving high-level quantum secure communication. As research deepened, researchers discovered that many classical light sources can also be used to achieve ghost diffraction, greatly promoting its application in secure communications in everyday life. In a classic ghost diffraction experiment, a laser beam shines on a rotating frosted glass, generating a pseudothermal light field with a random speckle distribution. The beam then passes through a non-polarizing beam splitter, generating two beams with identical distributions, forming two optical paths. One path, called the test path, contains an object, and the intensity of the beam is recorded by a point detector after it strikes the object. The other path, called the reference path, contains no object, and the beam propagates through free space before being detected by a high-resolution area detector. Neither path alone can capture image information of the object. Ghost diffraction technology correlates the information collected by the point detector in the test path with the information collected by the area detector in the reference path to obtain information about the object. This imaging method gives ghost diffraction advantages such as strong anti-interference and high sensitivity. Therefore, ghost diffraction technology has shown great application potential in secure communications, biomedicine, precision measurement, military defense and other fields.

[0003] In today's digital age, data and information security has become the lifeline of all industries. Optical image encryption technology, with its unique physical properties, has demonstrated significant advantages in the field of information security. When encryption is performed through traditional optical imaging systems, images are directly acquired by pixel sensors, which results in the problem of relying on precise optical devices and stable optical paths. Slight vibrations or temperature fluctuations may cause the optical path to shift, making it impossible to correctly decrypt the encrypted image. Applying ghost diffraction systems to optical image encryption can solve this problem. Unlike the "what you see is what you get" nature of traditional imaging methods, it uses the statistical correlation characteristics of the light field for imaging. Even if part of the optical path is blocked or interfered with by noise, the image can still be restored through statistical correlation characteristics. Therefore, ghost diffraction has a natural image encryption function, and its information acquisition and reconstruction are highly resistant to interference.

[0004] Existing ghost diffraction encryption technology usually encrypts the light field information of static targets, and it is difficult to fully record and encrypt the position change information of dynamic targets. Summary of the Invention

[0005] In view of the above situation, the main purpose of the present invention is to propose a high-precision ghost diffraction encryption method for dynamic targets to solve the above technical problems.

[0006] The present invention proposes a high-precision ghost diffraction encryption method for dynamic targets, the method comprising the following steps:

[0007] Step 1: Observe the number of interference fringes moving on the object using a Michelson interferometer and perform phase calculation to obtain a set of observed phase change values. Use a conversion function to convert the set of observed phase change values to obtain a first-level ciphertext, and use the conversion function as the first-level key.

[0008] Step 2: Construct four reference functions based on the principle of the four-step phase shift method, and multiply the four reference functions with the first-level ciphertext to obtain four reference quantities respectively;

[0009] Step 3: Obtain an optical element and build a ghost diffraction optical path based on the optical element and the first-level ciphertext;

[0010] Step 4: Based on the ghost diffraction optical path, perform ghost diffraction operations on the first-level ciphertext and the four reference quantities to obtain the second-level ciphertext and the second-level key respectively;

[0011] Step 5: Based on the ghost diffraction principle, a second-order correlation operation is performed on the secondary key and the secondary ciphertext to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities, respectively; based on the four-step phase shift principle, the ghost diffraction images of the four reference quantities are processed and phase calculation is performed to obtain the phase of the restored primary ciphertext Fourier image; the ghost diffraction image of the primary ciphertext is processed and an inverse Fourier operation is performed on the phase of the restored primary ciphertext Fourier image to obtain the restored primary ciphertext;

[0012] Step 6: Decrypt the recovered first-level ciphertext using the first-level key to obtain the recovered high-precision displacement information of the object on the optical axis.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The present invention introduces ghost diffraction technology into the encryption process. Ghost diffraction uses the statistical correlation characteristics of the light field to perform imaging. Even when part of the light path is blocked or there is noise interference, the image can still be restored through the statistical correlation characteristics, effectively enhancing the anti-interference ability of the encryption method proposed in the present invention.

[0015] 2. The present invention converts the displacement information of an object into phase information for encryption. Since a small movement of an object will produce a large phase change, measuring the phase information of a dynamic target using the interference principle can sensitively reflect its small displacement, thereby improving the detection accuracy of the object displacement, thereby effectively improving the accuracy of the encryption method proposed by the present invention and broadening the scope of application of the encryption method proposed by the present invention.

[0016] 3. The present invention encrypts the object's position change process by assigning it to the original object in the form of phase, that is, converting the video content of the object's movement into image content. While ensuring the encryption of the moving target and its displacement information, it significantly reduces the amount of encrypted data and effectively improves the encryption efficiency.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flowchart of the steps of a high-precision ghost diffraction encryption method for dynamic targets proposed by the present invention;

[0019] Figure 2 This is a method framework diagram of a high-precision ghost diffraction encryption method for dynamic targets proposed by the present invention. DETAILED DESCRIPTION

[0020] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0021] These and other aspects of the embodiments of the present invention will become clear with reference to the following description and accompanying drawings. In these descriptions and accompanying drawings, some specific implementations of the embodiments of the present invention are specifically disclosed to illustrate some ways of implementing the principles of the embodiments of the present invention, but it should be understood that the scope of the embodiments of the present invention is not limited thereto.

[0022] See also Figure 1 This embodiment provides a high-precision ghost diffraction encryption method for dynamic targets, the method comprising the following steps:

[0023] Step 1: Use a Michelson interferometer to observe the number of movement of interference fringes on the object and perform phase calculation to obtain a set of observed phase change values. Use a conversion function to convert the set of observed phase change values to obtain a first-level ciphertext, and use the conversion function as the first-level key.

[0024] See also Figure 2 In step 1, the Michelson interferometer is used to observe the number of interference fringes moving on the object and perform phase calculation to obtain a set of observed phase change values. The set of observed phase change values is transformed using a conversion function to obtain a first-level ciphertext, and the conversion function is used as the first-level key. Specifically, the following sub-steps are included:

[0025] Get a transmission plate, use the transmission plate as the object to be encrypted, construct a function based on the transmission plate, and obtain the object transmission function. The following relationship exists in the corresponding process:

[0026] ;

[0027] in, represents the object transmission function, represents the coordinates of the object, Indicates that it has been processed by the rectangular function. represents the length of the transmission plate, and ;

[0028] Obtain a Michelson interferometer and use the Michelson interferometer to observe the number of interference fringes moving on the object once every second to obtain a set of measured interference fringes moving numbers. ;

[0029] in, represents the set of measured interference fringe movement numbers, and ; represents the number of observation time points, and ; Indicates the The number of interference fringe movements obtained by the measurement is represents the index of the number of measurements, and ;

[0030] The set of measured interference fringe movement numbers and the wavelength of the light source are calculated to obtain the high-precision displacement of the object on the optical axis. The following relationship exists in the corresponding process:

[0031] ;

[0032] in, Indicates the high-precision displacement of an object on the optical axis, Indicates the difference between the current position and the initial position of the object. Indicates the current position of the object. represents the wavelength of the light source, and ;

[0033] Based on the set of measured interference fringe movement numbers, the measured interference fringe movement numbers are subjected to phase calculation to obtain a set of observed phase change values. The following relationship exists in the corresponding process:

[0034] ;

[0035] in, Indicates the The phase change value of the observation, represents pi;

[0036] The phase width is set based on the set of observed phase change values, and the set of observed phase change values is transformed using the transformation function to obtain new phase information. The following relationship exists in the corresponding process:

[0037] ;

[0038] in, Represents the new phase information, represents the set of observed phase change values, and ; represents the phase width, and ;

[0039] Assign the new phase information to the object to obtain the first-level ciphertext, and use the conversion function as the first-level key. The following relationship exists in the corresponding process:

[0040] ;

[0041] in, Indicates the first level ciphertext, Represents the phase information of the first-level ciphertext, represents the exponential function, Represents an imaginary unit.

[0042] Step 2: Construct four reference functions based on the principle of the four-step phase shift method, and multiply the four reference functions with the first-level ciphertext to obtain four reference quantities respectively.

[0043] In step 2, four reference functions are constructed based on the principle of the four-step phase shift method. The four reference functions are multiplied by the first-level ciphertext to obtain four reference quantities. The specific steps include the following:

[0044] Based on the principle of the four-step phase shift method, four reference functions are constructed to obtain four reference functions respectively. The following relationship exists in the corresponding process:

[0045] ;

[0046] in, represents the first reference function, represents the second reference function, represents the third reference function, represents the fourth reference function, represents the coordinates of the reference function, It means that after the exponential function processing, represents the coordinate interval in the frequency domain, and ; represents the resolution of the detector, and ; represents the distance from the object to the detector, and ;

[0047] Multiply the first-level ciphertext with the four reference functions to obtain four reference quantities. The following relationship exists in the corresponding process:

[0048] ;

[0049] in, Indicates the first reference quantity, represents the second reference quantity, represents the third reference quantity, Indicates the fourth reference quantity.

[0050] Step 3: Obtain optical elements and build a ghost diffraction light path based on the optical elements and the first-level ciphertext.

[0051] In step 3, a ghost diffraction optical path is constructed based on optical elements and the first-level ciphertext. The specific process is as follows:

[0052] Place the He-Ne laser, beam expander, collimating lens, aperture, polarizer, spatial light modulator, analyzer, aperture, condenser, first-level ciphertext, converging lens, and point detector in sequence.

[0053] It should be noted that the He-Ne laser is the light source, the beam expander is used to expand the diameter of the laser beam, the collimating lens is used to make the beam parallel, the aperture is used to limit the size of the beam, the polarizer and analyzer are used to adjust the polarization state of the light, the spatial light modulator is used to modulate the phase or amplitude of the light wave, the condenser and converging lens are used to focus the light beam, and the point detector is used to detect the intensity of the light source.

[0054] Step 4: Based on the ghost diffraction optical path, perform ghost diffraction operations on the first-level ciphertext and the four reference quantities to obtain the second-level ciphertext and the second-level key respectively.

[0055] In step 4, based on the ghost diffraction optical path, ghost diffraction operations are performed on the first-level ciphertext and the four reference quantities to obtain the second-level ciphertext, which specifically includes the following sub-steps:

[0056] Based on the ghost diffraction optical path, the first-level ciphertext and the four reference quantities are subjected to ghost diffraction operations respectively to obtain the ghost diffraction images of the first-level ciphertext and the ghost diffraction images of the four reference quantities respectively. The following relationship exists in the corresponding process:

[0057] ;

[0058] in, The ghost diffraction image representing the first-level ciphertext, represents the intensity fluctuation correlation formula, Indicates the coordinates of the test light path detector, represents the coordinates of the reference light path detector, Indicates the light intensity, represents the distance from the light source to the object, and ; represents the Fourier image of the first-level ciphertext, represents the ghost diffraction image of the first reference quantity, represents the ghost diffraction image of the second reference quantity, represents the ghost diffraction image of the third reference quantity, represents the ghost diffraction image of the fourth reference quantity;

[0059] Based on the ghost diffraction operation, the detection value of the point detector in the ghost diffraction light path and the random speckle used to illuminate the object are recorded. The detection value of the point detector is used as the secondary ciphertext, and the random speckle is used as the secondary key. The following relationship exists in the corresponding process:

[0060] ;

[0061] in, Represents the detection value of the point detector, represents the coordinates of a random light source, Represents the light field distribution of the light source.

[0062] Step 5. Based on the ghost diffraction principle, perform a second-order correlation operation on the secondary key and the secondary ciphertext to obtain the ghost diffraction image of the first-level ciphertext and the ghost diffraction images of the four reference quantities respectively; based on the four-step phase shift principle, process the ghost diffraction images of the four reference quantities and perform phase calculation to obtain the phase of the restored first-level ciphertext Fourier image; process the ghost diffraction image of the first-level ciphertext and perform a Fourier inverse operation with the phase of the restored first-level ciphertext Fourier image to obtain the restored first-level ciphertext.

[0063] In step 5, a second-order correlation operation is performed on the secondary key and the secondary ciphertext based on the ghost diffraction principle to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities, respectively. The ghost diffraction images of the four reference quantities are processed based on the four-step phase shift method principle, and phase calculation is performed to obtain the phase of the restored primary ciphertext Fourier image. The ghost diffraction image of the primary ciphertext is processed and an inverse Fourier operation is performed on the phase of the restored primary ciphertext Fourier image to obtain the restored primary ciphertext. The specific sub-steps include:

[0064] Based on the ghost diffraction principle, the secondary key and the secondary ciphertext are subjected to a second-order correlation operation to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities. Based on the four-step phase shift method, the ghost diffraction images of the four reference quantities are processed to obtain the intermediate quantities. The following relationship exists in the corresponding process:

[0065] ;

[0066] in, Indicates the intermediate quantity, represents the conjugate of the Fourier image of the first-level ciphertext;

[0067] The phase of the intermediate quantity is calculated to obtain the phase of the recovered first-level ciphertext Fourier image. The following relationship exists in the corresponding process:

[0068] ;

[0069] in, represents the phase of the Fourier image of the recovered first-level ciphertext, and ; Indicates the The phase of the Fourier image of the first-level ciphertext at each detection point, represents the index of the detection point, and ; Indicates the The phase of the intermediate quantity at each detection point, Indicates the The phase of the Fourier image of the first-level ciphertext at each detection point;

[0070] It should be noted that when season .

[0071] The ghost diffraction image of the first-level ciphertext is processed to obtain the amplitude of the Fourier image of the restored first-level ciphertext. The following relationship exists in the corresponding process:

[0072] ;

[0073] in, Represents the amplitude of the recovered first-level ciphertext Fourier image;

[0074] Based on the phase and amplitude of the Fourier image of the recovered first-level ciphertext, an inverse Fourier operation is performed to obtain the recovered first-level ciphertext. The following relationship exists in the corresponding process:

[0075] ;

[0076] in, Represents the recovered first-level ciphertext, represents the coordinates in the frequency domain, represents positive infinity, Represents negative infinity.

[0077] Step 6: Decrypt the recovered first-level ciphertext using the first-level key to obtain the recovered high-precision displacement information of the object on the optical axis.

[0078] In step 6, the recovered first-level ciphertext is decrypted using the first-level key to obtain the recovered high-precision displacement information of the object on the optical axis. The specific steps include the following:

[0079] The phase information is obtained based on the recovered first-level ciphertext, and the inverse operation is performed on the phase information based on the first-level key to obtain the set of recovered observed phase change values. The following relationship exists in the corresponding process:

[0080] ;

[0081] in, represents the set of recovered observed phase change values;

[0082] The recovered set of observed phase change values is inversely calculated with the wavelength of the light source to obtain the high-precision displacement information of the recovered object on the optical axis. The following relationship exists in the corresponding process:

[0083] ;

[0084] in, Represents the restored high-precision displacement information of the object on the optical axis.

[0085] It should be understood that, although the various steps in the flow chart of each embodiment of the present invention are shown in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless otherwise specified herein, the execution of these steps is not strictly limited in order, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0086] It should be understood that various components of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0087] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0088] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A high-precision ghost diffraction encryption method for dynamic targets, characterized in that: The method comprises the following steps: Step 1: Observe the number of interference fringes moving on the object using a Michelson interferometer and perform phase calculation to obtain a set of observed phase change values. Use a conversion function to convert the set of observed phase change values to obtain a first-level ciphertext, and use the conversion function as the first-level key. Step 2: Construct four reference functions based on the principle of the four-step phase shift method, and multiply the four reference functions with the first-level ciphertext to obtain four reference quantities respectively; Step 3: Obtain an optical element and build a ghost diffraction optical path based on the optical element and the first-level ciphertext; Step 4: Based on the ghost diffraction optical path, perform ghost diffraction operations on the first-level ciphertext and the four reference quantities to obtain the second-level ciphertext and the second-level key respectively; Step 5: Based on the ghost diffraction principle, a second-order correlation operation is performed on the secondary key and the secondary ciphertext to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities, respectively; based on the four-step phase shift principle, the ghost diffraction images of the four reference quantities are processed and phase calculation is performed to obtain the phase of the restored primary ciphertext Fourier image; the ghost diffraction image of the primary ciphertext is processed and an inverse Fourier operation is performed on the phase of the restored primary ciphertext Fourier image to obtain the restored primary ciphertext; Step 6: Decrypt the recovered first-level ciphertext using the first-level key to obtain the recovered high-precision displacement information of the object on the optical axis; In step 4, based on the ghost diffraction optical path, ghost diffraction operations are performed on the first-level ciphertext and the four reference quantities to obtain the second-level ciphertext and the second-level key respectively, which specifically includes the following sub-steps: Based on the ghost diffraction optical path, the first-level ciphertext and the four reference quantities are subjected to ghost diffraction operations respectively to obtain the ghost diffraction images of the first-level ciphertext and the ghost diffraction images of the four reference quantities respectively. The following relationship exists in the corresponding process: ； in, The ghost diffraction image representing the first-level ciphertext, represents the intensity fluctuation correlation formula, Indicates the coordinates of the test light path detector, represents the coordinates of the reference light path detector, represents the distance from the object to the detector, Indicates the distance from the light source to the object. Indicates the light source intensity, represents the Fourier image of the first-level ciphertext, represents the ghost diffraction image of the first reference quantity, represents the ghost diffraction image of the second reference quantity, represents the ghost diffraction image of the third reference quantity, represents the ghost diffraction image of the fourth reference quantity, represents the imaginary unit, represents the coordinate interval in the frequency domain; Based on the ghost diffraction operation, the detection value of the point detector in the ghost diffraction light path and the random speckle used to illuminate the object are recorded. The detection value of the point detector is used as the secondary ciphertext, and the random speckle is used as the secondary key. The following relationship exists in the corresponding process: ； in, Represents the detection value of the point detector, represents the coordinates of a random light source, represents the light field distribution of the light source, represents the coordinates of the object, Indicates the first level ciphertext, Represents the exponential function.

2. The high-precision ghost diffraction encryption method for dynamic targets according to claim 1, characterized in that: In step 1, a Michelson interferometer is used to observe the number of interference fringes moving on the object, and a phase calculation is performed to obtain a set of observed phase change values. The set of observed phase change values is transformed using a conversion function to obtain a first-level ciphertext, and the conversion function is used as a first-level key. Specifically, the following sub-steps are included: Obtain a transmission plate, use the transmission plate as the object to be encrypted, construct a function based on the transmission plate, and obtain the object transmission function; Obtain a Michelson interferometer, and use the Michelson interferometer to observe the number of interference fringe movements of the object once every second to obtain a set of measured interference fringe movement numbers; The set of measured interference fringe movement numbers is calculated with the wavelength of the light source to obtain the high-precision displacement of the object on the optical axis; Based on the set of measured interference fringe movement numbers, performing phase calculation on the measured interference fringe movement numbers to obtain a set of observed phase change values; The phase width is set based on the set of observed phase change values, and the set of observed phase change values is transformed using a transformation function to obtain new phase information; The new phase information is assigned to the object to obtain the first-level ciphertext, and the conversion function is used as the first-level key.

3. The high-precision ghost diffraction encryption method for dynamic targets according to claim 2, characterized in that: Get a transmission plate, use the transmission plate as the object to be encrypted, construct a function based on the transmission plate, and obtain the object transmission function. The following relationship exists in the corresponding process: ； in, represents the object transmission function, Indicates that it has been processed by the rectangular function. Indicates the length of the transmission plate; In the step of calculating the set of measured interference fringe movement numbers and the wavelength of the light source to obtain the high-precision displacement of the object on the optical axis, the following relationship exists in the corresponding process: ； in, Indicates the high-precision displacement of an object on the optical axis, Indicates calculating the difference between the current position and the initial position of the object. Indicates the current position of the object. represents the set of measured interference fringe movement numbers, Indicates the wavelength of the light source; In the step of performing phase calculation on the measured interference fringe movement number based on the set of measured interference fringe movement numbers to obtain a set of observed phase change values, the following relationship exists in the corresponding process: ； in, Indicates the The phase change value of the observation, represents pi, Indicates the The number of interference fringe movements obtained by the measurement is An index indicating the number of measurements; In the step of setting the phase width based on the set of observed phase change values and transforming the set of observed phase change values using a transformation function to obtain new phase information, the following relationship exists in the corresponding process: ； in, Represents the new phase information, represents the set of observed phase change values, represents the phase width; In the steps of assigning the new phase information to the object, obtaining the first-level ciphertext, and using the conversion function as the first-level key, the following relationship exists in the corresponding process: ； in, Indicates the phase information of the first-level ciphertext.

4. The high-precision ghost diffraction encryption method for dynamic targets according to claim 3, characterized in that: In step 2, four reference functions are constructed based on the principle of the four-step phase shift method, and the four reference functions are multiplied by the first-level ciphertext to obtain four reference quantities, which specifically includes the following sub-steps: Based on the principle of the four-step phase shift method, four reference functions are constructed to obtain four reference functions respectively; Multiply the first-level ciphertext with the four reference functions to obtain four reference quantities respectively.

5. The high-precision ghost diffraction encryption method for dynamic targets according to claim 4, characterized in that: Based on the principle of the four-step phase shift method, four reference functions are constructed to obtain four reference functions respectively. The following relationship exists in the corresponding process: ； in, represents the first reference function, represents the second reference function, represents the third reference function, represents the fourth reference function, represents the coordinates of the reference function, It means processed by exponential function; In the step of multiplying the first-level ciphertext with the four reference functions to obtain four reference quantities, the following relationship exists in the corresponding process: ； in, Indicates the first reference quantity, represents the second reference quantity, represents the third reference quantity, Indicates the fourth reference quantity.

6. The high-precision ghost diffraction encryption method for dynamic targets according to claim 1, characterized in that: In step 5, a second-order correlation operation is performed on the secondary key and the secondary ciphertext based on the ghost diffraction principle to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities, respectively; the ghost diffraction images of the four reference quantities are processed based on the four-step phase shift method principle, and phase calculation is performed to obtain the phase of the restored primary ciphertext Fourier image; the ghost diffraction image of the primary ciphertext is processed and an inverse Fourier operation is performed on the phase of the restored primary ciphertext Fourier image to obtain the restored primary ciphertext, which specifically includes the following sub-steps: Based on the ghost diffraction principle, a second-order correlation operation is performed on the secondary key and the secondary ciphertext to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities. Based on the four-step phase shift method, the ghost diffraction images of the four reference quantities are processed to obtain the intermediate quantity. Perform phase calculation on the intermediate quantity to obtain the phase of the recovered first-level ciphertext Fourier image; Processing the ghost diffraction image of the first-level ciphertext to obtain the amplitude of the Fourier image of the restored first-level ciphertext; Based on the phase and amplitude of the Fourier image of the restored first-level ciphertext, an inverse Fourier operation is performed to obtain the restored first-level ciphertext.

7. The high-precision ghost diffraction encryption method for dynamic targets according to claim 6, characterized in that: Based on the ghost diffraction principle, the secondary key and the secondary ciphertext are subjected to a second-order correlation operation to obtain the ghost diffraction image of the primary ciphertext and the ghost diffraction images of the four reference quantities. Based on the four-step phase shift method, the ghost diffraction images of the four reference quantities are processed to obtain the intermediate quantities. The following relationship exists in the corresponding process: ； in, Indicates the intermediate quantity, represents the conjugate of the Fourier image of the first-level ciphertext; In the step of calculating the phase of the intermediate quantity to obtain the phase of the recovered first-level ciphertext Fourier image, the following relationship exists in the corresponding process: ； in, represents the phase of the Fourier image of the recovered first-level ciphertext, Indicates the The phase of the Fourier image of the first-level ciphertext at each detection point, Represents the index of the detection point, Indicates the The phase of the intermediate quantity at each detection point, Indicates the The phase of the Fourier image of the first-level ciphertext at each detection point; In the step of processing the ghost diffraction image of the first-level ciphertext to obtain the amplitude of the Fourier image of the restored first-level ciphertext, the following relationship exists in the corresponding process: ； in, Represents the amplitude of the recovered first-level ciphertext Fourier image; In the step of performing an inverse Fourier operation based on the phase and amplitude of the Fourier image of the recovered first-level ciphertext to obtain the recovered first-level ciphertext, the following relationship exists in the corresponding process: ； in, Represents the recovered first-level ciphertext, represents the coordinates in the frequency domain, represents positive infinity, Represents negative infinity.

8. The high-precision ghost diffraction encryption method for dynamic targets according to claim 7, characterized in that: In step 6, the recovered first-level ciphertext is decrypted using the first-level key to obtain the recovered high-precision displacement information of the object on the optical axis, which specifically includes the following sub-steps: The phase information is obtained based on the recovered first-level ciphertext, and the phase information is inversely operated based on the first-level key to obtain a set of recovered observed phase change values; The set of recovered observed phase change values is inversely calculated with the wavelength of the light source to obtain the recovered high-precision displacement information of the object on the optical axis.

9. The high-precision ghost diffraction encryption method for dynamic targets according to claim 8, characterized in that: The phase information is obtained based on the recovered first-level ciphertext, and the inverse operation is performed on the phase information based on the first-level key to obtain the set of recovered observed phase change values. The following relationship exists in the corresponding process: ； in, represents the set of recovered observed phase change values; In the step of inversely calculating the recovered set of observed phase change values and the wavelength of the light source to obtain the recovered high-precision displacement information of the object on the optical axis, the following relationship exists in the corresponding process: ； in, Represents the restored high-precision displacement information of the object on the optical axis.

Images