A post-quantum multi-layer embedded encryption image reversible information hiding method and system and application thereof

Abstract

This invention discloses a post-quantum multi-layer embedded encrypted image reversible information hiding method, system, and its application, comprising: constructing a chain-like embedding key system supporting L≥3 layers. Multi-layer information embedding is performed using a prediction error expansion-based method: in the first layer, the encrypted message is embedded into the original image, and the key generated using OFB mode is used for stream encryption and compression before being encrypted using a Kyber public key; subsequent i-th layers perform similar operations based on the ciphertext image of the previous layer to generate multi-layer ciphertext images. At the receiving end, the keystream is decrypted and reconstructed using a Kyber private key. Starting from the final ciphertext image, decryption, decompression, and information extraction are performed from layer L to layer 1, losslessly restoring the original message and original image of all layers. This invention combines post-quantum security, high scalability, error isolation, and high embedding capacity, making it suitable for privacy image management scenarios requiring multi-party collaboration, such as cloud computing and medical image privacy protection.

Description

Technical Field

[0001] This invention relates to the fields of cryptography and information hiding technology, specifically to a reversible information hiding method for encrypted images (RDH-EI), and more particularly to a post-quantum secure multi-layer embedding method suitable for scenarios such as cloud computing and medical image privacy protection. Background Technology

[0002] With the breakthrough development of quantum computing technology, traditional public-key cryptosystems (such as RSA and ECC) built on classical mathematical problems (such as large number factorization and discrete logarithms) face the threat of being cracked, making existing encryption domain information hiding schemes that rely on such cryptography vulnerable to long-term security risks. Meanwhile, in practical applications, it is often necessary to embed multiple types of information from different parties (such as patient privacy, search tags, and audit logs) layer by layer into encrypted images, ensuring that all hidden information and the original carrier image can be completely and losslessly extracted and recovered.

[0003] However, existing reversible information hiding schemes typically have the following limitations when addressing the above requirements: First, most schemes are based on traditional cryptographic systems that lack post-quantum resistance, making them unable to withstand future quantum computing attacks; second, most existing schemes are limited to single-layer or two-layer embedding architectures, making it difficult to flexibly and scalably support multi-layer information management needs of three or more layers; in addition, the encryption modes used in some schemes may cause errors generated during information embedding or transmission to spread during decryption, thereby affecting the lossless recovery of the original image and the reliability of the system.

[0004] Therefore, designing a highly secure and reversible information hiding method that can resist the threat of quantum computing, support flexible embedding of multi-layer information, and ensure the isolation of operational errors at each layer has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a method, system, and application for reversible information hiding in post-quantum multilayer embedded encrypted images.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for reversible information hiding in post-quantum multilayer embedded encrypted images includes the following steps:

[0008] Step S1: Construct a post-quantum key and multi-layer embedded key system, including:

[0009] S1.1: Generate the quantum public key pk and private key sk based on the Kyber algorithm;

[0010] S1.2: Based on the Output Feedback Mode (OFB) of the block cipher, generate L embedded keys kh1,kh2,…,kh L Where L≥3 represents the number of embedding layers;

[0011] S1.3: Distribute the keys. The public key pk is made public, and the private key sk is distributed to the image receiver. Each embedded key kh i Distribute to the corresponding information embedding party;

[0012] Step S2: Preprocess the L-layer message to be embedded and calculate the pixel prediction error of the original image;

[0013] Step S3: Perform multi-layer information embedding based on the Kyber algorithm and OFB pattern, including:

[0014] S3.1: In the first layer, the first layer message ciphertext c1 processed by kh1 is embedded into the original image. After stream encryption and matrix compression using the key generated by OFB, Kyber encryption is performed using the public key pk to generate the first layer marked ciphertext image I1.

[0015] S3.2: For the i-th layer, 2≤i≤L, obtain the ciphertext image I output by the (i-1)-th layer. i-1 The ciphertext c of the i-th layer message after processing by khi i Embedded in the I i-1 The corresponding intermediate image, after being stream-encrypted and matrix-compressed using the key generated by OFB, is then Kyber-encrypted using the public key pk to generate the i-th layer marked ciphertext image I. i ;

[0016] S3.3: Output the final L-th layer labeled ciphertext image I L ;

[0017] Step S4: The image receiving end processes the final tagged encrypted image I. L Perform synchronous decryption and multi-layered information reverse extraction, including:

[0018] S4.1: Reconstruct all L-layer keys kh1 to kh using the public key pk in OFB block cipher mode. L ;

[0019] S4.2: Perform reverse extraction from layer L to layer 1, sequentially decrypting, decompressing, and stream cipher decryption, and recover the intermediate image of the previous layer and the ciphertext of the current layer based on the prediction error expansion method. i ;

[0020] S4.3: Key kh reconstructed using OFB mode iciphertext with each layer of messages c i Perform an XOR operation to recover all the original messages m from layer L. i And ultimately, the original image is restored without loss.

[0021] Further, in step S1.2, the generation of multi-layer embedded keys based on OFB mode adopts a chain rule: using the public key pk as the seed key, a random initialization vector IV is generated, the generation function of the first-layer embedded key kh1 is kh1=LED_OFB(pk, IV, p1), and the generation function of the i-th layer embedded key kh i The generating function is kh i =LED_OFB(pk, p i ), where p1 and p i Layer 1 and Layer i are based on IV and kh, respectively. i-1 The generated pseudo-random information, i≥2.

[0022] Furthermore, in step S2, the message m to be embedded in the i-th layer is... i The preprocessing is as follows: m i With the embedded key kh i The corresponding sequence is XORed bitwise to obtain the ciphertext c. i That is, c i =m i ⊕kh i .

[0023] Furthermore, in step S2, the pixel prediction error calculation adopts the diamond prediction method, and the prediction error e ij =x ij -x ij ', where x ij 'For pixels x ij The floor value of the average of the four adjacent pixels (top, bottom, left, and right).

[0024] Further, in steps S3.1 and S3.2, the stream encryption using the key generated by OFB specifically involves: cyclically shifting the pixel left by 6 bits, and then combining it with the key kh generated by the OFB of the corresponding layer. i Perform a bitwise XOR operation.

[0025] Furthermore, in steps S3.1 and S3.2, the matrix compression is used to compress the image data after stream encryption in order to reduce the amount of data subsequently encrypted by Kyber.

[0026] Furthermore, in steps S3.1 and S3.2, the method of embedding the ciphertext into the image is a histogram shifting method based on Prediction Error Expansion (PEE).

[0027] Further, in step S4.2, the reverse extraction process specifically includes: for the i-th layer, decrypting the Kyber ciphertext with the private key sk to obtain compressed data; and decompressing the compressed data to obtain image I. i '; to I i After performing a 6-bit right shift operation on the pixel ', it is combined with the key kh generated by the OFB mode of the i-th layer. i XOR, to obtain the intermediate image I i-1 ', and extract the ciphertext c from it. i .

[0028] This invention also discloses an application of the post-quantum multilayer embedded encrypted image reversible information hiding method described above in medical image privacy protection, digital rights tracking, or cloud-based encrypted data management. The L-layer messages correspond to different dimensions of information from different participants, including but not limited to at least three of the following information that requires privacy protection: privacy metadata, search tags, audit logs, and copyright identifiers.

[0029] This invention also discloses a post-quantum multilayer embedding encrypted image reversible information hiding system, used to implement the above-mentioned post-quantum multilayer embedding encrypted image reversible information hiding method, specifically including:

[0030] The key management module is configured to generate a public key pk and a private key sk based on the Kyber algorithm, and to generate L embedded keys kh1, kh2, …, kh based on the output feedback OFB mode. L Where L≥3;

[0031] The preprocessing module is configured to process the messages to be embedded at each layer. i Preprocessing is performed, and pixel prediction error is calculated on the original image;

[0032] A multi-layer embedding module, communicating with at least three different information embedding endpoints, is configured as follows: At the first layer, the processed first-layer message is embedded into the original image, stream-encrypted and compressed using the key generated by OFB, and then Kyber-encrypted using the public key pk to obtain the first-layer ciphertext image; for subsequent i-th layers, the processed i-th layer message is embedded into the intermediate image corresponding to the (i-1)-th layer ciphertext image, stream-encrypted and compressed using the key generated by OFB, and then Kyber-encrypted to obtain the i-th layer ciphertext image, and the final marked ciphertext image I is output. L ;

[0033] The extraction and recovery module is configured to use the public key pk to extract the tagged ciphertext image I. L Decryption is performed, and the keys for all L layers are reconstructed based on the OFB block cipher encryption mode. Then, Kyber decryption, decompression, stream cipher decryption, and information extraction are performed sequentially from layer L to layer 1 to recover the original message m of all L layers without loss.i And the original image.

[0034] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program, implements the steps of the above-described post-quantum multilayer embedded encrypted image reversible information hiding method.

[0035] The present invention also discloses a computer-readable storage medium storing a computer program thereon, characterized in that the computer program, when executed by a processor, implements the steps of the above-described post-quantum multilayer embedded encrypted image reversible information hiding method.

[0036] Compared with the prior art, the advantages of the present invention are as follows:

[0037] 1. High scalability: It supports a multi-layer information embedding architecture with three layers (L≥3) or more, which can meet the needs of complex scenarios involving multiple parties and multi-dimensional information management (for example, in medical imaging scenarios, multiple types of information such as patient privacy, search tags, audit logs, and device identification can be embedded at the same time), breaking through the limitation of existing technologies that are usually limited to single-layer or two-layer embedding.

[0038] 2. Post-quantum security: By introducing the Kyber post-quantum cryptography algorithm based on the Module-LWE hard problem for core key negotiation and data encryption, this invention can resist future quantum computing attacks, solving the fundamental security defect of traditional schemes (such as schemes based on RSA and ElGalmal) that do not have post-quantum resistance.

[0039] 3. Error isolation: The output feedback (OFB) block cipher is used to generate keys for each layer, which ensures that errors generated during embedding or transmission at a certain layer are limited to that layer and will not spread to other layers or the original image data. This guarantees the overall reliability under multi-layer operation and the robustness of lossless recovery of the original image.

[0040] 4. High embedding capacity: By combining embedding and compression techniques such as prediction error extended histogram shifting and matrix compression, the overall information embedding rate is greatly improved while ensuring image visual quality and reversibility. Experiments show that its total embedding capacity far exceeds that of traditional two-layer embedding schemes.

[0041] 5. High Efficiency: The encryption and decryption efficiency of the Kyber algorithm is close to that of symmetric encryption on modern computing platforms. Therefore, this invention achieves post-quantum security and high capacity while still meeting the processing efficiency requirements of practical applications. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart of a post-quantum multilayer embedded encrypted image reversible information hiding method according to an embodiment of the present invention;

[0044] Figure 2 These are effect diagrams at different stages of the four-layer embedding process of the Lenna image in this embodiment of the invention; where (a) is the original image, and (b)-(i) are the images corresponding to the embedding and encryption of the first to fourth layers, respectively.

[0045] Figure 3 This is the change in information entropy after each layer of the Airplane is embedded in one embodiment of the present invention; where the horizontal axis 1 is the original image, and 2-9 are the images corresponding to the first to fourth layers of embedding and encryption, respectively.

[0046] Figure 4 This is a scatter plot of the correlation between the directions of adjacent pixels above each other in different processes of an Airplane image in one embodiment of the present invention; where (a) is the original image, and (b)-(i) are the images corresponding to the embedding and encryption of the first to fourth layers, respectively. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] This invention provides a method for reversible information hiding in post-quantum multilayer embedded encryption images, such as... Figure 1 As shown, the specific steps are as follows:

[0049] Step S1: Construction of Post-Quantum Keying and Embedded Keying Systems

[0050] S1.1: Kyber Key Generation: The key server runs the Kyber algorithm to generate a public key pk and a private key sk;

[0051] S1.2: OFB Multi-layer Embedded Key Generation: There are a total of four embedding layers, which can be divided into privacy metadata, retrieval tags, audit logs, and copyright identification layers, generating 4 embedding keys kh1,kh2,...,kh4;

[0052] S1.2.1: Initial Key Generation: Generate a random initialization vector IV using the Kyber public key pk as the seed key, and use pk as the encryption and decryption key for the OFB block cipher;

[0053] S1.2.2: OFB chain rule generation of multi-layer embedded keys: A chain mechanism is used where the output of the previous layer's ciphertext is the seed for the current layer's keystream. The OFB key kh for the i-th layer (1≤i≤4) is generated. i The generation rules are as follows:

[0054] Layer 1: kh1=LED_OFB(pk, IV, p1), where LED is the block cipher algorithm, kh1 has the same length as the number of bits in the image, and p1 is the pseudo-random information generated by the first layer based on IV;

[0055] Layer i≥2: kh i =LED_OFB(pk, p i ), where p i For the i-th layer based on kh i-1 The generated pseudo-random information ensures that each layer of key stream is independent and synchronized;

[0056] S1.3: Key distribution: Public key pk is made public; private key sk is distributed to the image receiving end; kh1 is distributed to the image providing end, responsible for the first layer of embedding; kh2 to kh4 are distributed to the corresponding data hiding end respectively, such as kh2 to the retrieval system and kh3 to the auditor; all kh1 to kh4 are jointly distributed to the image receiving end to ensure access control isolation.

[0057] Step S2: Multi-layer message preprocessing and pixel prediction error calculation

[0058] S2.1: Multi-layer message encryption: Encryption of message m at the i-th layer i (1≤i≤4), m i With kh i The ciphertext c is obtained by bitwise XORing of the sequence. i (c) i =m i ⊕kh i );

[0059] S2.2: Pixel Prediction Error Calculation: Calculate the prediction error e of the original image using the diamond prediction method. ij =x ij -x ij ', where x ij '= , that is, x ij 'For pixels x ij The floor value of the average value of pixels v1 to v4 at the four positions (top, bottom, left, and right).

[0060] Step S3: 4-layer embedding based on Kyber algorithm and OFB

[0061] S3.1: First layer embedding:

[0062] By applying a histogram shifting method based on prediction error expansion, the c1 information is embedded into the original image, thus obtaining an image I1' with embedded ciphertext. After cyclically shifting the pixels of image I1' left by 6 bits, stream encryption is performed to generate image I1'', i.e., p 1j =(p 0j <<<6)⊕kh1,where p 0j Let I1' be the pixel in the image, and kh1 be the first-level embedding key generated by the OFB chain rule. A matrix compression algorithm is used to compress the pixels in I1''. After compression, the image is encrypted using the public key pk using Kyber encryption to generate the encrypted image I1.

[0063] S3.2: Embedding at level i ≥ 2:

[0064] Ciphertext acquisition at layer i: Ciphertext image output at layer (i-1) I i-1 ;

[0065] Hierarchical embedding rule: Apply a histogram shifting method based on prediction error expansion to c i Information is embedded in the original image to obtain image I with embedded ciphertext. i ', for image I i Image I is generated by cyclically shifting pixels 6 bits to the left and then performing stream encryption. i '', i.e., p ij =(p i-1j <<<6)⊕khi, where p i-1j For image I i-1 'pixel, kh i The i-th layer embedding key generated for the OFB chain rule. A matrix compression algorithm is used to process I. i The pixels are compressed, and then each pixel is encrypted using the public key pk to generate an encrypted image I. i .

[0066] S3.3: Multi-layer embedding termination condition: When all 4 layers of messages m1 to m4 have been embedded, the final multi-layer marked ciphertext image I4 is output.

[0067] Step 4: OFB and Kyber Algorithm Synchronous Decryption and Multi-Layer Information Extraction

[0068] 4.1: Auxiliary Information Parsing: The image receiver acquires I4 and auxiliary information;

[0069] 4.2: Kyber decapsulation and OFB key stream reconstruction: Reconstruct all layer key streams kh1 to kh4 using the public key pk based on OFB mode, following the chain rule in step 1.2.2;

[0070] 4.3: Reverse extraction from layer i=4 to i=1:

[0071] Layer 4 extraction: Decrypt the encrypted image I4 using the private key sk, decompress it into I4' using a matrix compression algorithm, and then perform stream cipher decryption, i.e., p 3j =(p 4j >>>6)⊕kh4,where p 4j Let I3 be pixel I4', and kh4 be the fourth-layer embedding key generated by the OFB chain rule. A histogram shifting method based on prediction error expansion is applied to recover image I3 and extract the ciphertext information c4.

[0072] Extraction from layers i=3 to i=1: Decrypt the encrypted image I using the private key sk. i And decompressed into I using a matrix compression algorithm. i ', and perform stream cipher decryption, i.e., p i-1j =(p ij >>>6)⊕kh i , where p ij For image I i 'pixel, kh i The i-th layer embedding key is generated for the OFB chain rule. A histogram shifting method based on prediction error expansion is applied to recover image I. i-1 And extract the ciphertext information c i .

[0073] 4.4: Original Message Recovery: Obtaining c i Afterwards, restore plaintext m i =c i ⊕kh i ,(1≤i≤4), where kh i The i-th layer embedding key generated for OFB chain rules.

[0074] To verify the performance of this embodiment, different experiments were conducted, and the specific results are shown below:

[0075] To verify the safety of this invention, a series of statistical safety parameters will be used for measurement. The main safety parameters include Shannon entropy, chi-square test, normalized average change intensity (UACI), pixel change rate (NPCR), mean absolute error (MAE), and correlation coefficient (horizontal and vertical).

[0076] Taking Baboon as an example, Table 1 shows the first layer of embedded image I 1 aFirst layer encrypted image I 1 e Second layer embedded image I 2 a Second layer encrypted image I 2 e Third layer embedded image I 3 a Third-layer encrypted image I 3 e Fourth layer embedded image I 4 a Fourth layer encrypted image I 4 e The table shows the security parameter statistics, which can be seen from the first layer of embedded image I. 1 a If only the embedding operation was performed and no encryption operation was performed, and security is not considered, the correlation coefficients of the other embedded images and encrypted images with respect to the original image I are close to 0, the Shannon entropy is close to 8, the NPCR is close to 100%, the MAE and UACI are both large enough, and the chi-square test is also small enough compared to the original image I. This indicates that the embedded images or encrypted images of each layer have sufficiently large differences from the original image, which further verifies that the present invention has very high security.

[0077] Table 1. Quantitative Results of Security Indicators for Baboon Images

[0078]

[0079] Taking Baboon as an example, Table 2 shows the four-layer application architecture designed for a specific scenario (Layer 1: User Privacy, Layer 2: Image Retrieval, Layer 3: Audit Log, Layer 4: Device Identifier), with embedding capacities of 10,000, 10,000, 10,000, and 10,000 bits respectively, for a total capacity of 40,000 bits. Experimental results are shown in Table 2.

[0080] Table 2. Embedding performance test results for specific scenarios with L=4 layers.

[0081] number of floors Embedded content Embedded capacity (bits) Extraction accuracy (%) Restore PSNR (dB) 1 Patient privacy 10,000 100 ∞ 2 Image retrieval 10,000 100 ∞ 3 Audit Log 10,000 100 ∞ 4 Equipment identification 10,000 100 ∞ total - 40,000 100 ∞

[0082] The four-layer scheme enables the independent embedding of four types of core information in a specific scenario, significantly improving scalability and practicality; the information extraction accuracy of all layers is 100%, and the PSNR of each layer and the original image is restored to ∞ dB (completely lossless), meeting the requirements for lossless storage and transmission of specific images.

[0083] In summary, this invention achieves a balance between high security, high capacity, and high efficiency by combining Kyber's post-quantum security characteristics with OFB's fault-resistance characteristics, making it suitable for scenarios involving multidimensional information management and lossless data recovery.

[0084] Appendix Figure 2-4 The study further demonstrated the visual changes, information entropy changes, and pixel correlations of the image during processing, confirming the above conclusions.

[0085] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0086] In another embodiment, a post-quantum multilayer embedded encrypted image reversible information hiding system is provided, which corresponds one-to-one with the post-quantum multilayer embedded encrypted image reversible information hiding method in the above embodiments. Specifically, it includes:

[0087] The key management module is configured to generate a public key pk and a private key sk based on the Kyber algorithm, and to generate L embedded keys kh1, kh2, …, kh based on the output feedback OFB mode. L Where L≥3;

[0088] The preprocessing module is configured to process the messages to be embedded at each layer. i Preprocessing is performed, and pixel prediction error is calculated on the original image;

[0089] A multi-layer embedding module, communicating with at least three different information embedding endpoints, is configured as follows: At the first layer, the processed first-layer message is embedded into the original image, stream-encrypted and compressed using the key generated by OFB, and then Kyber-encrypted using the public key pk to obtain the first-layer ciphertext image; for subsequent i-th layers, the processed i-th layer message is embedded into the intermediate image corresponding to the (i-1)-th layer ciphertext image, stream-encrypted and compressed using the key generated by OFB, and then Kyber-encrypted to obtain the i-th layer ciphertext image, and the final marked ciphertext image I is output. L ;

[0090] The extraction and recovery module is configured to use the private key sk on the tagged ciphertext image I. L Decryption is performed, and the keys for all L layers are reconstructed based on the OFB block cipher encryption mode. Then, Kyber decryption, decompression, stream cipher decryption, and information extraction are performed sequentially from layer L to layer 1 to recover the original message m of all L layers without loss. i And the original image.

[0091] For specific limitations regarding a post-quantum multilayer embedded encrypted image reversible information hiding system, please refer to the limitations of the post-quantum multilayer embedded encrypted image reversible information hiding method above, which will not be repeated here. Each module in the above system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.

[0092] In another embodiment of the present invention, a terminal device is provided, comprising a processor and a memory. The memory stores a computer program, which includes program instructions. The processor executes the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing and control core of the terminal, suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions to achieve a corresponding method flow or corresponding function. The processor described in this embodiment of the present invention can be used in the operation of a post-quantum multilayer embedded encrypted image reversible information hiding method.

[0093] In another embodiment of the present invention, a storage medium is provided, specifically a computer-readable storage medium (Memory). This computer-readable storage medium is a memory device in a terminal device used to store programs and data. It is understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and extended storage media supported by the terminal device. The computer-readable storage medium provides storage space that stores the terminal's operating system. Furthermore, this storage space also stores one or more instructions suitable for loading and execution by a processor. These instructions can be one or more computer programs (including program code). It should be noted that the computer-readable storage medium here can be high-speed RAM or non-volatile memory, such as at least one disk storage device.

[0094] One or more instructions stored in a computer-readable storage medium can be loaded and executed by a processor to implement the corresponding steps of the post-quantum multilayer embedded encryption image reversible information hiding method in the above embodiments; one or more instructions in the computer-readable storage medium are loaded and executed by a processor.

[0095] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), etc.

[0096] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0097] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for reversible information hiding in post-quantum multilayer embedded encrypted images, characterized in that, Includes the following steps: Step S1: Construct a post-quantum key and multi-layer embedded key system, including: S1.1: Generate the quantum public key pk and private key sk based on the Kyber algorithm; S1.2: Based on the Output Feedback (OFB) mode of block ciphers, generate L embedded keys kh1,kh2,…,kh L Where L≥3 represents the number of embedding layers; S1.3: Distribute the keys. The public key pk is made public, and the private key sk is distributed to the image receiver. Each embedded key kh i Distribute to the corresponding information embedding party; Step S2: Preprocess the L-layer message to be embedded and calculate the pixel prediction error of the original image; Step S3: Perform multi-layer information embedding based on the Kyber algorithm and OFB pattern, including: S3.1: In the first layer, the first layer message ciphertext c1 processed by kh1 is embedded into the original image. After stream encryption and matrix compression using the key generated by OFB mode, Kyber encryption is performed using the public key pk to generate the first layer marked ciphertext image I1. S3.2: For the i-th layer, 2≤i≤L, obtain the ciphertext image I output by the (i-1)-th layer. i-1 , will pass through kh i The processed ciphertext c of the i-th layer message i Embedded in the I i-1 The corresponding intermediate image, after being stream-encrypted and matrix-compressed using the key generated in OFB mode, is then Kyber-encrypted using the public key pk to generate the i-th layer marked ciphertext image I. i ; S3.3: Output the final L-th layer labeled ciphertext image I L ; Step S4: The image receiving end processes the final tagged encrypted image I. L Perform synchronous decryption and multi-layered information reverse extraction, including: S4.1: Reconstruct the keystream kh1 to kh using the public key pk in OFB block cipher mode. L ; S4.2: Perform reverse extraction from layer L to layer 1, sequentially decrypting, decompressing, and stream cipher decryption, and recover the intermediate image of the previous layer and the ciphertext of the current layer based on the prediction error expansion method. i ; S4.3: Utilizing the reconstructed OFB keystream kh i ciphertext with each layer of messages c i Perform an XOR operation to recover all the original messages m from layer L. i And ultimately, the original image is restored without loss.

2. The method according to claim 1, characterized in that, In step S1.2, the generation of multi-layer embedded keys based on OFB mode adopts a chain rule: using the public key pk as the seed key, a random initialization vector IV is generated, the generation function of the first-layer embedded key kh1 is kh1=LED_OFB(pk, IV, p1), and the generation function of the i-th layer embedded key kh i The generating function is kh i =LED_OFB(pk, p i ), where p1 and p i Layer 1 and Layer i are based on IV and kh, respectively. i-1 The generated pseudo-random information, i≥2.

3. The method according to claim 1 or 2, characterized in that, In step S2, the message m to be embedded in the i-th layer is... i The preprocessing is as follows: m i With the embedded key kh i The corresponding sequence is XORed bitwise to obtain the ciphertext c. i That is, c i =m i ⊕kh i .

4. The method according to claim 1, characterized in that, In step S2, the pixel prediction error is calculated using the diamond prediction method, and the prediction error e ij =x ij -x ij ', where x ij 'For pixels x ij The floor value of the average of the four adjacent pixels (top, bottom, left, and right).

5. The method according to claim 1, characterized in that, In steps S3.1 and S3.2, the stream encryption of the key generated in OFB mode specifically involves: cyclically shifting the pixel left by 6 bits, and then encrypting it with the OFB key stream kh of the corresponding layer. i Perform a bitwise XOR operation.

6. The method according to claim 1, characterized in that, In steps S3.1 and S3.2, the matrix compression is used to compress the image data after stream encryption using the key generated by OFB, so as to reduce the amount of data subsequently encrypted by Kyber.

7. The method according to claim 1, characterized in that, In steps S3.1 and S3.2, the method of embedding the ciphertext into the image is a histogram shifting method based on prediction error expansion.

8. The method according to claim 1, characterized in that, In step S4.2, the reverse extraction process specifically includes: for the i-th layer, decrypting the Kyber ciphertext with the private key sk to obtain compressed data; and decompressing the compressed data to obtain image I. i '; to I i After performing a 6-bit right shift operation on the pixel ', it is combined with the key kh generated by the OFB mode of the i-th layer. i XOR, to obtain the intermediate image I i-1 ', and extract the ciphertext c from it. i .

9. An application of a post-quantum multilayer embedded encrypted image reversible information hiding method according to any one of claims 1-8 in medical image privacy protection, digital rights tracking, or cloud-based encrypted data management, characterized in that, The L-layer messages correspond to different dimensions of information from different participants, including but not limited to at least three of the following: privacy metadata, search tags, audit logs, and copyright identifiers.

10. A post-quantum multilayer embedded encrypted image reversible information hiding system, characterized in that, The method for implementing any one of claims 1 to 8 specifically includes: The key management module is configured to generate a public key pk and a private key sk based on the Kyber algorithm, and to generate L embedded keys kh1, kh2, …, kh based on the output feedback OFB mode. L Where L≥3; The preprocessing module is configured to process the messages to be embedded at each layer. i Preprocessing is performed, and pixel prediction error is calculated on the original image; A multi-layer embedding module, communicating with at least three different information embedding ends, is configured as follows: At the first layer, the processed first-layer message is embedded into the original image, stream-encrypted and compressed using a key generated in OFB mode, and then Kyber-encrypted using the public key pk to obtain the first-layer ciphertext image; for subsequent i-th layers, the processed i-th layer message is embedded into the intermediate image corresponding to the (i-1)-th layer ciphertext image, stream-encrypted and compressed using a key generated in OFB mode, and then Kyber-encrypted to obtain the i-th layer ciphertext image, and the final marked ciphertext image I is output. L ; The extraction and recovery module is configured to use the private key sk on the tagged ciphertext image I. L Decryption is performed, and according to step S1.2, all L-layer keys are reconstructed based on OFB mode. Then, Kyber decryption, decompression, stream cipher decryption, and information extraction are performed sequentially from layer L to layer 1 to recover all original L-layer messages m without loss. i And the original image.

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