CN112948850B - Rotary laminated encryption cylinder, encryption method and decryption method - Google Patents
Rotary laminated encryption cylinder, encryption method and decryption method Download PDFInfo
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
- G06F21/60—Protecting data
- G06F21/602—Providing cryptographic facilities or services
Abstract
The invention relates to a rotary laminated encryption cylinder, an encryption method and a decryption method. The encryption method comprises the following steps: taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information through a rotary laminated encryption lens barrel to generate ciphertext information intensity distribution; rotating the whole rotary laminated encryption lens barrel for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption lens barrel for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption lens barrel; and determining a plurality of ciphertext images according to the ciphertext information intensity distribution. The invention has low operation difficulty and high safety.
Description
Technical Field
The invention relates to the field of information encryption, in particular to a rotary laminated encryption cylinder, an encryption method and a decryption method.
Background
Since human beings enter the information society, information security has been paid attention to in the scientific community as a problem that can affect the development of national military, politics and economy. How to ensure the safe transmission of secret information, and the secret information can not be intercepted or destroyed by an attacker in the way is an important technical problem in information security. Therefore, for the information to be transmitted, the information transmitting party needs to systematically hide and disguise the information to generate ciphertext with redundant information, and the process is called an encryption process; while the person allowed to receive the information needs the corresponding key to extract this secret information and reject the unimportant redundant information, a process called decryption. The information hiding and encrypting process has wide application, plays an important role in trademark copyright protection, personal privacy protection and the like, and is a booster for promoting the development of information security technology.
Traditional information encryption and hiding technology is based on mathematics, cryptography, information theory and other subjects to encrypt and hide information, and can be traced to ancient steganography at the earliest. In recent years, with the development and progress of optical, electronic and acoustic fields, information encryption mechanisms are expanding continuously, and diversity of many subjects is reflected. The intersection of the information security and other fields improves the security and the key space of the key on one hand, and also embodies the advantages of various disciplines in the encryption field on the other hand. In recent 20 years, optics has been an emerging discipline, and the value in the field of information encryption has been waiting for more people to dig.
In 1995, refregier and Javidi first proposed a method of encrypting an image using a dual random phase plate and a 4f system (DPRE system), opening the door for optical information encryption. In 2013, university of chinese academy of sciences Shishi et al have combined it with a DRPE system to provide a new information encryption system that introduces physical parameters in layered imaging. The optical probe in the laminated imaging is used as a novel secret key, so that the space of the secret key is expanded, and the safety and the robustness of the whole encryption system are improved. However, the DPRE system has poor safety due to the small key space, namely, only two random phase plates; although the optical probe is added to the traditional laminated encryption system to be a novel secret key, the optical probe needs to be moved to scan, the requirement on light beams is high, and the actual operation difficulty is high.
Disclosure of Invention
The invention aims to provide a rotary laminated encryption cylinder, an encryption method and a decryption method, which are used for solving the problems of high operation difficulty and poor safety of the traditional laminated encryption system.
In order to achieve the above object, the present invention provides the following solutions:
a rotary stacked encryption cylinder comprising: the first phase plate, the first lens, the second phase plate, the second lens and the ciphertext receiving screen are sequentially arranged;
the first lens is connected with the second phase plate through threads, so that the second phase plate, the second lens and the ciphertext receiving screen integrally move in the encryption process, the telescopic distance is determined, and the image to be encrypted is encrypted according to the telescopic distance.
A method of rotating stacked encryption, comprising:
taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information through a rotary laminated encryption lens barrel to generate ciphertext information intensity distribution;
rotating the whole rotary laminated encryption lens barrel for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption lens barrel for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption lens barrel;
and determining a plurality of ciphertext images according to the ciphertext information intensity distribution.
Optionally, the ciphertext information intensity distribution is:
exp[jM 2]}； wherein ,the method is characterized in that the method is used for distributing the intensity of ciphertext information, i is iteration times, n is ciphertext number, CCD is intensity at the position of a receiving screen, FT is Fourier transform, and +.>The Fresnel transformation is that the distance is f-d, f is the focal length of the lens, d is the telescopic distance,/and/or>Fresnel transformation with distance f and Probe 1 As initial probe, object i n The intensity of the nth ciphertext information guessed at the ith iteration is j which is an imaginary unit and M 1 For the first phase plate, t (x, y) is the phase modulation function of the lens, M 2 Is a second phase plate.
A method of rotating stack decryption, comprising:
rotating the initial probe for a plurality of times in a counterclockwise direction, determining a plurality of dummy probes, and guessing an initial complex amplitude of the original image;
scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution;
replacing the amplitude of the guessed ciphertext intensity distribution with the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude;
sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave;
updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted;
generating an original image according to the updated image object function to be encrypted; the original image is an original image to be encrypted.
Optionally, the guessed ciphertext intensity distribution is:
t(x，y)}·exp[jM 2]}； wherein ,for guessed ciphertext information intensity distribution, i is iteration number, n is ciphertext number, FT is Fourier transform, +>The Fresnel transformation is that the distance is f-d, f is the focal length of the lens, d is the telescopic distance,/and/or>For fresnel transformation of distance f, probe n Is a dummy probe, object i ng e For the initial guess complex amplitude of the n-th ciphertext information corresponding to the object to be encrypted, j is an imaginary number unit, M 1 For the first phase plate, t (x, y) is the lens phase modulation function, M 2 Is a second phase plate.
Optionally, the intensity distribution of the guessed ciphertext after the amplitude replacement is:
wherein ,/>The intensity distribution of the guessed ciphertext after replacing the amplitude is +.>Is the ciphertext information intensity distribution.
Optionally, the image outgoing wave is:
wherein ,is an image outgoing wave.
Optionally, the updated image object function to be encrypted is:
wherein Object is i+1 ng e In order to update the image object function to be encrypted, the y is the searching step length, the beta is the minimum value, and the x is the conjugate operation.
A rotary stacked encryption and decryption method, comprising:
taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information through a rotary laminated encryption lens barrel to generate ciphertext information intensity distribution;
rotating the whole rotary laminated encryption lens barrel for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption lens barrel for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption lens barrel;
determining a plurality of ciphertext images according to the ciphertext information intensity distribution;
rotating the initial probe for a plurality of times in a counter-clockwise direction, determining a plurality of dummy probes, and guessing an initial complex amplitude of the original image;
scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution;
replacing the amplitude of the guessed ciphertext intensity distribution with the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude;
sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave;
updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted;
generating an original image according to the updated image object function to be encrypted; the original image is the image to be encrypted.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects: the invention provides a rotary laminated encryption cylinder, an encryption method and a decryption method, wherein an image to be encrypted is recorded in an eccentric rotation mode, and in addition, the invention additionally increases the telescopic distance, takes the telescopic distance as an encryption key, and can decrypt the encrypted image only by accurately knowing the telescopic distance, thereby further enhancing the safety and the robustness of the traditional laminated encryption system.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a diagram of a rotary laminated encryption cylinder according to the present invention;
FIG. 2 is a flow chart of a method for encrypting a rotary overlay layer according to the present invention;
FIG. 3 is a flowchart of a method for decrypting a rotating stack according to the present invention;
FIG. 4 is a flowchart of a decryption algorithm in the rotary lamination decryption method according to the present invention;
FIG. 5 is a schematic diagram of an encrypted image scanned by a probe after a rotary laminated encryption cylinder provided by the invention rotates by different rotation angles; fig. 5 (a) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 0 °, fig. 5 (b) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 60 °, fig. 5 (c) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 120 °, fig. 5 (d) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 180 °, fig. 5 (e) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 240 °, and fig. 5 (f) is a schematic diagram of an image to be encrypted when the rotation angle of the rotary laminated encryption cylinder is 300 °.
FIG. 6 is a schematic diagram of the complex amplitude of a simulated object to be encrypted according to the present invention; fig. 6 (a) is an amplitude diagram of an image to be encrypted, and fig. 6 (b) is a phase diagram of the image to be encrypted;
FIG. 7 is a diagram of six pieces of ciphertext information provided by the present invention; fig. 7 (a) is a schematic diagram of the first ciphertext information, fig. 7 (b) is a schematic diagram of the second ciphertext information, fig. 7 (c) is a schematic diagram of the third ciphertext information, fig. 7 (d) is a schematic diagram of the fourth ciphertext information, fig. 7 (e) is a schematic diagram of the fifth ciphertext information, and fig. 7 (f) is a schematic diagram of the sixth ciphertext information;
FIG. 8 is a diagram showing the comparison of six pieces of ciphertext information with a portion of a real image provided by the present invention; fig. 8 (a) is a schematic diagram of a real image corresponding to the first ciphertext information, fig. 8 (b) is a schematic diagram of a real image corresponding to the second ciphertext information, fig. 8 (c) is a schematic diagram of a real image corresponding to the third ciphertext information, fig. 8 (d) is a schematic diagram of a real image corresponding to the fourth ciphertext information, fig. 8 (e) is a schematic diagram of a real image corresponding to the fifth ciphertext information, and fig. 8 (f) is a schematic diagram of a real image corresponding to the sixth ciphertext information;
FIG. 9 is a diagram of the decrypted result provided by the present invention; fig. 9 (a) is a decryption amplitude diagram, and fig. 9 (b) is a decryption phase diagram;
fig. 10 is a diagram showing the decryption effect of the probe eccentricity (400 ) when encrypting, wherein the probe eccentricity is (0, 50); fig. 10 (a) is a schematic diagram of decryption amplitude of the probe eccentricity (400 ) at the time of decryption, and fig. 10 (b) is a schematic diagram of decryption phase of the probe eccentricity (400 ) at the time of decryption, with the probe eccentricity (0, 50) at the time of encryption;
FIG. 11 is a graph showing the decryption effect of 50 for the probe telescoping distance and 30 for the probe telescoping distance during decryption; fig. 11 (a) is a schematic diagram of decryption amplitude in which the probe stretch distance at encryption is 50 and the probe stretch distance at decryption is 30, and fig. 11 (b) is a schematic diagram of decryption phase in which the probe stretch distance at encryption is 50 and the probe stretch distance at decryption is 30;
FIG. 12 is a diagram showing the effect of decrypting according to [060120180240300] when the probe rotation angle key is [180240300060120] and decrypting; FIG. 12 (a) is a schematic diagram of the decryption amplitude according to [060120180240300] when the probe rotation angle key is [180240300060120] during encryption, and FIG. 12 (b) is a schematic diagram of the decryption phase according to [060120180240300] when the probe rotation angle key is [180240300060120] during decryption; fig. 12 (c) is a schematic diagram of decryption amplitude according to [060120180240300] to crack and increase the eccentric distance when the probe rotation angle key is [180240300060120] during encryption, and fig. 12 (d) is a schematic diagram of decryption phase according to [060120180240300] to crack and increase the eccentric distance when the probe rotation angle key is [180240300060120] during encryption;
fig. 13 is a schematic view of decryption effect when the telescopic distance d=0 provided by the present invention; fig. 13 (a) is a schematic diagram of decryption amplitude when the telescopic distance d=0, and fig. 13 (b) is a schematic diagram of decryption phase when the telescopic distance d=0;
FIG. 14 is a schematic diagram of a processed ciphertext image provided by the present invention; FIG. 14 (a) is a schematic diagram of a processed ciphertext provided by the present invention; fig. 14 (b) is a schematic diagram of the decryption amplitude of the ciphertext after processing, and fig. 14 (c) is a schematic diagram of the decryption phase of the ciphertext after processing.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a rotary laminated encryption cylinder, an encryption method and a decryption method, which have low operation difficulty and high safety.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
FIG. 1 is a diagram of a rotary laminated encryption cylinder according to the present invention, comprising: the first phase plate M1, the first lens L1, the second phase plate M2, the second lens L2 and the ciphertext receiving screen are sequentially arranged; the first lens L1 is in threaded connection with the second phase plate M2, so that the second phase plate M2, the second lens L2 and the ciphertext receiving screen integrally move in the encryption process, the expansion distance is determined, and the image to be encrypted is encrypted according to the expansion distance.
The first lens L1 and the second phase plate M2 can be connected by threads or a plurality of precise structures, so that the second phase plate M2, the second lens L2 and the ciphertext receiving screen can integrally move leftwards by d (d is more than or equal to 0 and less than or equal to d < f), and d is a telescopic distance, thus a secret key of the telescopic distance can be added, if the accurate telescopic distance d cannot be obtained, the ciphertext cannot be cracked, the telescopic distance is that the whole system is not limited to be encrypted and hidden in a Fourier domain, and Fresnel transformation and Fourier transformation are combined, so that the encryption effect is more excellent, and the safety problem of secret information is better ensured; meanwhile, the telescopic distance can also regulate and control the length of the system so as to adapt to different working environments and be better applied to production and life and secret work.
Fig. 2 is a flowchart of a rotary laminated encryption method provided by the present invention, as shown in fig. 2, a rotary laminated encryption method includes:
step 201: and taking the probe key with the eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information through a rotary laminated encryption lens barrel to generate ciphertext information intensity distribution.
The ciphertext information intensity distribution is:
exp[jM 2]}； wherein ,for ciphertext information intensity distribution, i is iteration number, n is ciphertext number, CCD is intensity at the receiving screen position (because this position is the position for placing CCD pinhole camera in the lamination), FT is Fourier transform, and #>The Fresnel transformation with the distance f-d is that the focal length of the lens (the focal length of the first lens and the focal length of the second lens are the same), and the telescopic distance is that +.>For fresnel transformation of distance f, probe 1 As initial probe, object i n For the nth part of the object to be encrypted, j is the imaginary unit sqrt (-1), M 1 For the first phase plate, t (x, y) is the lens phase modulation function, M 2 Is a second phase plate.
Step 202: and rotating the whole rotary laminated encryption lens barrel for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption lens barrel for any angle each time to cover an image to be encrypted and obtain the ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption lens barrel.
Step 203: and determining a plurality of ciphertext images according to the ciphertext information intensity distribution.
In practical application, the rotary laminated encryption method of the invention is specifically as follows:
step 1: first, a Probe key Probe having a certain eccentric distance (center is shifted up by 100 pixels) is set 1 As an initial probe, the probe scans a part of information of an Object (lena) to be encrypted which is shifted up from the center.
Step 2: part of information of the object to be encrypted scanned by the probe is modulated by a first phase plate M1 adjacent to the object to be encrypted, subjected to Fresnel transformation of a distance f and lens modulation, and subjected to Fresnel transformation of a distance f-d. Then modulated by the second phase plate M2, and then subjected to a fourier transform to reach the ciphertext receiving screen as shown. The first part of the object to be encrypted is encrypted, ciphertext information is generated, and the intensity distribution expression is as follows:
step 3: the whole rotary laminated encryption lens barrel is rotated clockwise (anticlockwise) when viewed against the direction of the light source, and can be rotated by any angle at a time (generally within 360 degrees, since more than 360 degrees can find the equivalent angle within 360 degrees), and n scans are ensured to cover all the information to be encrypted.
Step 4: after each rotation of the sample, the ciphertext information 2, 3, 4 … n-1, n is obtained through a series of transformations in the step 1, and the intensity expression is as follows:
step 5: and (3) ending the encryption process to obtain six ciphertext pictures covered with white noise, wherein part of information of the object to be encrypted is hidden.
Fig. 3 is a flowchart of a method for decrypting a rotating stack according to the present invention, as shown in fig. 3, a method for decrypting a rotating stack, including:
step 301: the initial probe is rotated a plurality of times in a counter-clockwise direction, a plurality of dummy probes are determined, and an initial complex amplitude of the original image is guessed. The initial complex amplitude of the guessed original image is typically set to the full 1 matrix at the beginning of the decryption process.
Step 302: and scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution.
The guessed ciphertext intensity distribution is:
wherein (1)>The intensity distribution of ciphertext information is that i is iteration number, n is ciphertext number, FT is Fourier transform, < >>The Fresnel transformation with the distance f-d is that the focal length of the lens (the focal length of the first lens and the focal length of the second lens are the same), and the telescopic distance is that +.>For fresnel transformation of distance f, probe n Is a dummy probe, object i ng e For the initial guess complex vibration of the n-th ciphertext information corresponding to the object to be encrypted, j is the imaginary number unit sqrt (-1), M 1 For the first phase plate, t (x, y) is the lens phase modulation function, M 2 Is a second phase plate.
Step 303: and replacing the amplitude of the guessed ciphertext intensity distribution by the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude.
The guessed ciphertext intensity distribution after the amplitude replacement is:
wherein ,/>The intensity distribution of the guessed ciphertext after replacing the amplitude is +.>Is the ciphertext information intensity distribution.
Step 304: and sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave.
The image outgoing wave is:
wherein ,is an image outgoing wave.
Step 305: updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted.
The updated image object function to be encrypted is as follows:
wherein Object is i+1 ng e For updated image object function to be encrypted, the method comprises the following stepsFor the search step, β is the minimum value and x is the conjugate operation.
Step 306: generating an original image according to the updated image object function to be encrypted; the original image is an original image to be encrypted.
In practical application, the rotary lamination decryption method of the invention is specifically as follows:
the image scanned by the Probe key is changed but the position on the receiving screen is not changed due to the rotation of the whole system, so that the obtained ciphertext information and the Probe key Probe at the time of encryption are required to be processed 1 Some image processing is performed, and fig. 4 is a flowchart of a decryption algorithm in the rotating stack decryption method provided by the present invention, as shown in fig. 4.
Step 1: for the nth Zhang Miwen image, the ciphertext image is rotated counterclockwise (clockwise) by a corresponding angle (note that rotating the picture in MATLAB changes the size of the matrix, and the picture needs to be cut into the resolution of the original picture), the rotation angle is the same as the angle of the corresponding lens barrel rotated each time in the encryption process, and the image is adjusted back to the correct position.
As shown in fig. 5, taking 6 probes rotated 60 ° clockwise each time as an example: because the light field function of the optical probe must remain unchanged, the probe must be fixed, rotating the object to be encrypted, which is equivalent to the rotating probe scanning six parts of the object to be encrypted. However, unlike the rotation probe, the object itself rotates, and the scanned content also rotates, and if the information contained in the ciphertext No. 1 is used as a reference, the other 5 ciphertext pieces need to rotate counterclockwise by 60 °, 120 °, 180 °, 240 °, and 300 ° in order, and return to the reference of the ciphertext No. 1.
Step 2: the initial Probe 1 A counter-clockwise (clockwise) rotation is performed to obtain the n-th updated dummy probe for the next decryption process. This is due to the Probe 1 Is an eccentrically arranged circular hole, so that the diffraction pattern obtained by the probe No. 1 is also positioned in the middle of the receiving screen and is positioned upwards. Thus, a perfect six-petal shape is also seen by stacking six dummy probes.
Step 3:guessing an initial complex amplitude Object of an Object to be encrypted i ng e (x, y) and then begin the decryption algorithm iteration process.
Step 4: for the ith iteration, the guessed object is equivalent to being scanned by the nth dummy probe, so that the object function is multiplied by the probe to obtain the outgoing wave, and then the outgoing wave immediately passes through the first random phase plate M next to the object to be encrypted 1 Then through one Fresnel transformation to the lens L 1 The wave front is then modulated by a lens with a modulation function of tarnish (x, y) and then fresnel transformed by a distance f-d to a random phase plate M 2 Is a position of (c). Due to M 2 Located at the second lens L 2 The ciphertext receiving screen is positioned at the front focal plane of L 2 The back focal plane needs to undergo fourier transformation. Then the intensity distribution of the guessed ciphertext after passing through the encryption systemThe method comprises the following steps:
step 5: with actual ciphertext intensity distributionReplacement->Preserving its phase, obtaining +.>The method comprises the following steps:
step 6: obtainingAfterwards, the reverse process of encryption is performed: first pass through L 2 The lens performs an inverse Fourier transform and then divides by a random phase plate M 2 After the Fresnel inverse transformation with the distance f-d, dividing the Fresnel inverse transformation with the distance f by the modulation function t (x, y) of the lens, dividing the Fresnel inverse transformation with the distance f by the random phase plate M 1 Obtaining a new object emergent wave U:
step 7: and finally, updating the object function of the object to be encrypted by using a pseudo probe corresponding to each ciphertext:
where, y is the search step of the algorithm, generally set to 1, β is the minimum value set to prevent denominator from being 0, representing the conjugate operation.
Step 8: and repeating the steps 2-5, after updating the object function of the object to be encrypted each time, obtaining a part of contents (the information contained in the ciphertext used when the part of contents added each time are decrypted) which are solved by the object to be encrypted, until all ciphertext pictures are used up, and finishing an iteration.
Step 9: when the iteration times are increased to a certain degree, the iterative algorithm can be terminated when the relativity of the decrypted image and the object to be encrypted reaches a threshold value, and the clear original appearance of the whole object to be encrypted can be solved.
A rotary stacked encryption and decryption method, comprising:
and taking the probe key with the eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information through a rotary laminated encryption lens barrel to generate ciphertext information intensity distribution.
And rotating the whole rotary laminated encryption lens barrel for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption lens barrel for any angle each time to cover an image to be encrypted and obtain the ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption lens barrel.
And determining a plurality of ciphertext images according to the ciphertext information intensity distribution.
The initial probe is rotated a plurality of times in a counter-clockwise direction, a plurality of dummy probes are determined, and an initial complex amplitude of the original image is guessed.
And scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution.
And replacing the amplitude of the guessed ciphertext intensity distribution by the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude.
And sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave.
Updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted.
Generating an original image according to the updated image object function to be encrypted; the original image is the image to be encrypted.
Simulation:
1. simulation results.
Taking a 6-probe regular scan as an example, the rotation angle is 60 ° each time, the aperture radius is 200, and the eccentric distance is 199 (effect under test limit view). First, the amplitude of the object to be encrypted is lena. Jpg, and the phase is read she. Jpg, and the amplitude and phase of the object to be encrypted are shown in fig. 6.
When the picture is read, the amplitude and the phase are expanded into a matrix of 1000 x 1000 by using an immesize function, so that the sizes of the probe, the guessed object and the ciphertext information are set to 1000 x 1000 in the next simulation. Simulation of M using random number function rand 1 、M 2 And two random phase plates and store data in a local txt format to prevent different random number matrixes generated during encryption and decryption operation. After reading the pictureA round hole with a certain eccentric distance is made by using a Setpihole function, then a circulation function is set, wherein each circulation comprises rotating the small hole once, the round hole is realized by using imrotate, and then the transformation process in the 4 th step of the encryption algorithm is simulated, so that 6 ciphertext information is obtained, as shown in figure 7.
Before decryption, the last 5 pieces of 6 pieces of ciphertext information are reversely revolved around the ciphertext center for 60 degrees to return to the correct position. For conciseness and clarity of the reverse revolution process after the rotation of the sample, the corresponding pictures of the ciphertext and probe scan are shown in fig. 8. The decryption process is then started. It should be noted that the encryption algorithm and the decryption algorithm must be applied to the same main program, and the encrypted ciphertext cannot be stored as jdg or bmp type pictures or tif type pictures, because the original data after being stored as pictures is compressed and then cannot be read in the decryption program. The encrypted ciphertext information is directly called in a decryption function in the main program as much as possible.
The result after the decryption process is finally shown in fig. 9, and the iteration number is 5, it can be found that such an encryption system is feasible, and if all the known keys are mastered, the result very close to the real picture can be recovered when the iteration number is very small (5 times).
2. Key security.
(1) Eccentric distance key: the probe eccentricity during encryption is (0, 50), and the decrypting effect of the probe eccentricity during decryption (400 ) is shown in fig. 10.
(2) Telescoping distance key: the probe extension distance during encryption was 50, the extension distance during decryption was 30, and the decryption effect is shown in fig. 11.
(3) Rotation angle key: the probe rotation angle key is [180240300060120] when encrypting, and the result is shown in fig. 12 when decrypting according to [060120180240300 ].
The key needs to be matched with an eccentric distance key to be set, and the larger the eccentric distance is, the smaller the middle overlapped part is, and the less secret can be leaked. (the decryption map at the limit eccentric distance is shown below, and it can be found that the effect is very good).
3. And (5) testing system robustness.
(1) Noise immunity.
When the expansion distance d=0 (the fourier domain is necessary), the decryption effect is good by imnoise gaussian noise, the mean value 0 and the variance 0.1 on 6 pieces of ciphertext information, and the effect is shown in fig. 13.
(2) Resistance to clipping, the upper half of the ciphertext is set to 0, as shown in FIG. 14.
On the basis of the laminated encryption principle, the invention increases the unique rotation angle key, the eccentric distance key and the telescopic distance key, expands the key space and increases the safety and the robustness. Meanwhile, due to the special rotary laminated encryption mode, the probe needs to rotationally scan the object to be encrypted in the encryption process. Therefore, on the basis of the original system, the invention designs the rotary encryption cylinder which is highly integrated and can be subjected to physical processing, so that the possibility that the encryption system can be applied to actual work and life is greatly improved.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (9)
1. A rotary laminated encryption cylinder comprising: the first phase plate, the first lens, the second phase plate, the second lens and the ciphertext receiving screen are sequentially arranged;
the first lens is connected with the second phase plate through threads, so that the second phase plate, the second lens and the ciphertext receiving screen integrally move in the encryption process, the telescopic distance is determined, and an image to be encrypted is encrypted according to the telescopic distance;
the encryption process of the rotary laminated encryption cylinder comprises the following steps: taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information by a rotary laminated encryption cylinder to generate ciphertext information intensity distribution; rotating the whole rotary laminated encryption cylinder for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption cylinder for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption cylinder; and determining a plurality of ciphertext images according to the ciphertext information intensity distribution.
2. A rotary laminated encryption method, characterized in that the rotary laminated encryption method is applied to the rotary laminated encryption cylinder of claim 1, the rotary laminated encryption method comprising:
taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information by a rotary laminated encryption cylinder to generate ciphertext information intensity distribution;
rotating the whole rotary laminated encryption cylinder for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption cylinder for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption cylinder;
and determining a plurality of ciphertext images according to the ciphertext information intensity distribution.
3. The rotary laminated encryption method of claim 2, wherein the ciphertext information intensity distribution is:
wherein (1)>The method is characterized in that the method is used for distributing the intensity of ciphertext information, i is iteration times, n is ciphertext number, CCD is intensity at the position of a receiving screen, FT is Fourier transform, and +.>The Fresnel transformation is that the distance is f-d, f is the focal length of the lens, d is the telescopic distance,/and/or>For fresnel transformation of distance f, probe 1 As initial probe, object i n For the nth part of the object to be encrypted, j is the imaginary unit, M 1 For the first phase plate, t (x, y) is the lens phase modulation function, M 2 Is a second phase plate.
4. A rotary laminated decryption method, applied to the rotary laminated encryption cylinder of claim 1, comprising:
rotating the initial probe for a plurality of times in a counterclockwise direction, determining a plurality of dummy probes, and guessing an initial complex amplitude of the original image;
scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution;
replacing the amplitude of the guessed ciphertext intensity distribution with the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude;
sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave;
updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted;
generating an original image according to the updated image object function to be encrypted; the original image is an original image to be encrypted.
5. The method of claim 4, wherein the guessed ciphertext intensity distribution is:
wherein (1)>The intensity distribution of ciphertext information is that i is iteration number, n is ciphertext number, FT is Fourier transform, < >>The Fresnel transformation is that the distance is f-d, f is the focal length of the lens, d is the telescopic distance,/and/or>For fresnel transformation of distance f, probe n Is a dummy probe, object i nguess For the initial guess complex amplitude of the nth ciphertext information corresponding to the object to be encrypted, j is the imaginary number unit sqrt (-1), M 1 For the first phase plate, t (x, y) is the lens phase modulation function, M 2 Is a second phase plate.
6. The method of claim 5, wherein the intensity distribution of the guessed ciphertext after the replacing amplitude is:
wherein ,/>The intensity distribution of the guessed ciphertext after replacing the amplitude is +.>Is the ciphertext information intensity distribution.
7. The rotating stack decryption method according to claim 6, wherein the image exit wave is:
wherein ,is an image outgoing wave.
8. The method of claim 7, wherein the updated image object function to be encrypted is:
wherein Object is i+1 nguess For the updated image object function to be encrypted, alpha is the searching step length, beta is the minimum value, and the x is the conjugate operation.
9. A rotary laminated encryption/decryption method, wherein the rotary laminated encryption/decryption method is applied to the rotary laminated encryption cartridge of claim 1, the rotary laminated encryption/decryption method comprising:
taking a probe key with an eccentric distance as an initial probe, scanning image information of an image to be encrypted by using the initial probe, and processing the image information by a rotary laminated encryption cylinder to generate ciphertext information intensity distribution;
rotating the whole rotary laminated encryption cylinder for a plurality of times in a clockwise direction, and rotating the whole rotary laminated encryption cylinder for any angle each time to cover an image to be encrypted and obtain ciphertext information intensity distribution of the image to be encrypted after each rotation of the rotary laminated encryption cylinder;
determining a plurality of ciphertext images according to the ciphertext information intensity distribution;
rotating the initial probe for a plurality of times in a counter-clockwise direction, determining a plurality of dummy probes, and guessing an initial complex amplitude of the original image;
scanning the ciphertext image by using the pseudo probe through the rotary laminated encryption cylinder to generate guessed ciphertext intensity distribution;
replacing the amplitude of the guessed ciphertext intensity distribution with the amplitude of the ciphertext information intensity distribution, and determining the guessed ciphertext intensity distribution after replacing the amplitude;
sequentially passing the ciphertext image through a second lens, a second phase plate, a first lens and a first phase plate of the rotary laminated encryption cylinder to generate an image emergent wave;
updating the image object function to be encrypted according to the image emergent wave and the pseudo probe corresponding to each ciphertext image, and determining the updated image object function to be encrypted;
generating an original image according to the updated image object function to be encrypted; the original image is the image to be encrypted.
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| CN111563938A (en) * | 2020-03-27 | 2020-08-21 | 中国科学院大学 | Multi-image encryption and decryption method and system based on random phase layer and laminated diffraction |
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