Reversible image secret sharing method based on transform domain and application thereof

Abstract

The application discloses a reversible image secret sharing method based on a transform domain and application thereof, and the design process of the method comprises at least two stages: 1) a generation and embedding stage; and 2) a verification and reconstruction stage. The application aims at the risk of user privacy being leaked, malicious tampering and attack in the transmission and sharing process of secret data, and prevents the theft and abuse of secret data. The application completes the transmission of data in the transform domain and the sharing of data in the ciphertext domain, adopts secret sharing technology, image steganography technology and image processing technology, and guarantees the reliability of data transmission and sharing, ensures the high quality of image data and improves the security of secret image data transmission and sharing.

Description

Technical Field

[0001] This invention belongs to the field of industrial Internet of Things, specifically relating to a reversible image secret sharing method based on the transform domain and its application in face recognition. Background Technology

[0002] With the continuous development of information science and technology, creating an open and shared data resource environment has become a major trend. At the same time, personal privacy and data security issues have also become hot topics. Regarding data privacy and security, many researchers have studied various methods to ensure data is protected during transmission. It is common for secret data to be hidden in a single carrier. However, once the carrier is damaged or lost, the confidential information becomes inaccessible. To address this problem, Blakley and Shamir proposed a threshold secret-sharing scheme based on Lagrange multinomials. In this scheme, secret data is divided into multiple secret shares. Taking an (k,n) scheme as an example, the secret data can only be reconstructed jointly when k or more participants have submitted their secret shares, and no single party can obtain any information related to the secret data.

[0003] Random Grid-based Visual Image Secret Sharing (RGVSS) treats a black-and-white binary image as a grid with a 2D pixel array, where each pixel is either transparent or opaque. The average transmittance of each grid is 0.5, and there is no correlation between the values ​​of different pixels. Traditional secret image sharing schemes are limited to binary or grayscale images, and have limited image formats, while color images are the primary medium for network transmission today.

[0004] Furthermore, the shares generated by secret image sharing schemes are often noisy, which easily arouses suspicion from cyber attackers when transmitted over the internet. Therefore, combining information hiding technology with secret image sharing technology can provide a new solution to the current problem. Information hiding involves concealing meaningful information within another information called a public carrier to create a hidden carrier. Unauthorized attackers are unaware whether other information is hidden within this ordinary information, and even if they are, it is difficult to extract or remove the hidden information. The carrier used can be text, images, sound, and video, etc. However, solely pursuing visual effects in information hiding also has drawbacks. If the receiver cannot successfully extract the complete secret share data from the steganographic image, it hinders the reconstruction of the secret data. Therefore, reversible steganography technology is crucial for the data reconstruction stage.

[0005] However, existing image sharing schemes are mainly constrained by the threat of attacks during transmission, data irreversibility, and the uniformity of data formats.

[0006] On the other hand, as a benchmark technology for the practical application of artificial intelligence, facial recognition technology possesses characteristics such as naturalness, non-contact nature, imperceptibility, and concurrency. Currently, facial recognition technology is widely used in both public and commercial sectors. However, at the same time, the risks arising from the shortcomings of facial recognition technology and the legality risks of information processing pose significant challenges to the protection of facial information. Facial information is biometric information and belongs to sensitive personal information. Facial data in certain specific scenarios is confidential data, and there are certain security risks when it is transmitted and stored through the traditional Internet. Attackers or spies can detect and capture valuable image data by monitoring the Internet. Therefore, the confidentiality and integrity of images must be considered during the transmission, storage, and retrieval of images.

[0007] Traditional methods for storing, transmitting, and recovering secret images often focus on improving single-point security, such as image hiding and watermarking. However, these methods have the drawback that secret data often resides in a single information carrier; if the carrier is lost or damaged, the complete secret information cannot be obtained. Using multiple copies to solve this problem would significantly enhance security. Secret image sharing may be an excellent way to address this issue. Summary of the Invention

[0008] The purpose of this invention is to propose a reversible image secret sharing method based on the transform domain and its application, so as to solve some technical problems that still exist in the prior art described in the background.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] The present invention provides a reversible image secret sharing method based on the transform domain. This method can ensure that the participants in data sharing do not use additional bits for encryption and allows the participants to complete the authentication process without the participation of a trusted third party. In addition, the method can improve the visual effect of color steganographic images while ensuring reversible steganography.

[0011] The design process of this method includes at least two stages: 1) generation and embedding stage; 2) verification and refactoring stage.

[0012] On the other hand, the steps of generating and embedding secret shares using this method include at least: generating secret shares corresponding to the initial secret image and the verification image; and embedding secret shares.

[0013] In some embodiments of the present invention, generating the secret share corresponding to the initial secret image and the verification image includes one or a combination of the following steps:

[0014] A secret image S is encrypted using a (k,n) secret sharing scheme based on Lagrange polynomials, generating n encrypted images SC. i (i = 1, 2, ..., n);

[0015] A (2,2) visual secret sharing scheme based on random grids is used to verify an image S. A Encryption is performed to generate two secret shares S. A C1,S A C2; First, S A The pixel value in C1 is randomly selected from 0 and 1, and then the corresponding S is generated using the following formula. A C2:

[0016]

[0017] Then, the generated S A C1 and S A C2 is randomly assigned to the participating parties and a trusted third party who may be absent.

[0018] In some embodiments of the present invention, the secret share embedding is performed on a color carrier image by using discrete wavelet transform, singular value decomposition and improved LSB technology to embed the verification share and secret share into different channels of the color carrier image, thereby realizing the steganography of secret image data.

[0019] On the other hand, using this method for authentication and image reconstruction includes at least the following steps: 1) Authentication of participants; 2) Reconstruction of secret images.

[0020] In some embodiments of the present invention, participant authentication includes at least one or a combination of the following steps:

[0021] Each participant can verify with each other whether the other is an honest participant;

[0022] In cases involving a credible third party, participant P i Submit your own verification share S' A C i A trusted third party can decrypt the image S' by combining it with its own verification share D, thus obtaining a reconstructed verification image S'. A ; S' can be observed directly with the naked eye A and S A If the two images are identical, the verification process is passed; otherwise, the share is recorded as [missing information]. A trusted third party will participate in party P i Submitted secret share The broadcast was sent to all participating parties;

[0023] In the absence of a trusted third party, participant P i and participating party P q Each of them will give their secret share S' A C i and S' A C q Send it to the other party, and then each party decrypts the encrypted data; if the reconstructed verification image S' A With S A If they appear identical to the naked eye, then the verification process passes; otherwise, the share is recorded as... And broadcast it immediately to all participants.

[0024] In some embodiments of the present invention, reconstructing the secret image includes: an authenticated participant can submit their held secret image share S'C. i Once the number of submitted secret shares reaches k or more, the secret image S' is reconstructed.

[0025] This invention also provides a method for applying a transform domain-based reversible image secret sharing method to face recognition, comprising at least two stages: 1) face data acquisition, uploading, and storage; 2) face data recovery and recognition; wherein the face data acquisition, uploading, and storage step includes at least: camera acquisition of face image data, generation of an initial secret image and a secret share corresponding to a verification image based on the face image data and personal information; and secret share embedding; the face data recovery and recognition step includes at least: identity verification, secret image reconstruction, and face recognition.

[0026] This invention aims to address the risks of privacy breaches, malicious tampering, and attacks during the transmission and sharing of confidential data, preventing the theft and misuse of such data. The invention achieves data transmission in the transform domain and data sharing in the ciphertext domain, employing secret sharing technology, image steganography technology, and image processing technology to ensure the reliability of data transmission and sharing, guarantee high-quality image data, and improve the security of confidential image data transmission and sharing. Attached Figure Description

[0027] Figure 1 A flowchart illustrating a general scenario embodiment of the present invention is provided.

[0028] Figure 2 The workflow of an embodiment of the present invention applied to face recognition is shown. Detailed Implementation

[0029] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to better understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are only for illustrating the essential spirit of the technical solution of the present invention.

[0030] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0031] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0032] In the following description, in order to clearly demonstrate the structure and working method of the present invention, a number of directional terms will be used. However, terms such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and not as limiting terms.

[0033] Example 1: Implementation method of the method of the present invention in a general scenario

[0034] like Figure 1 As shown, the reversible secret image sharing method based on the transform domain in this embodiment has two stages in its design process: generation and embedding stage, and verification and reconstruction stage.

[0035] (1) Generation and Embedding Stage

[0036] The steps for generating and embedding secret shares using this method are as follows: generating secret shares corresponding to the initial secret image and the verification image; embedding secret shares.

[0037] (1.1) Generate the initial secret share

[0038] A secret image S is encrypted using a (k,n) secret sharing scheme based on Lagrange polynomials, generating n encrypted images SC. i (i = 1, 2, ..., n). The polynomial is as follows:

[0039] f(x) = (a0 + a1x + a2x) 2 +…+a k-1 x k-1 )mod P

[0040] Where a0 is the pixel value in the secret image, a1, a2, ..., a k-1 It is a random value, P is a prime number, k is a threshold parameter, and f(x) is a random value. i ) is the i-th pixel value corresponding to the secret share.

[0041] In addition, a (2,2) visual secret sharing scheme based on random grids is adopted for a verification image S. A Encryption is performed to generate two secret shares S. A C1,S A C2. First, let's consider S. A The pixel value in C1 is randomly selected from 0 and 1, and then the corresponding S is generated using the following formula. A C2:

[0042]

[0043] Then, the generated S A C1 and S A C2 is randomly assigned to the participating parties and a trusted third party who may be absent.

[0044] (1.2) Secret Share Embedding

[0045] For a color carrier image, the B channel is processed using Discrete Wavelet Transform (DWT) and Singular Value Decomposition (SVD). First, the pixel values ​​of the B channel are processed using DWT, generating four sub-bands: HH, HL, LH, and LL. Then, the LL sub-band is processed using SVD to extract the secret share SC. i It is embedded into the LL subband, and then the inverse operation of DWT is used to obtain a transformed B' channel image.

[0046] Steganography of the G channel in a color carrier image is performed using an improved Least Significant Bit (LSB), and the S... A C i The following formula is embedded into the carrier image:

[0047]

[0048] Where v' is the result of replacing the rightmost r bits of pixel v with the secret information in binary; r is the number of bits to be embedded, vr The rightmost r bits of the pixel value are binary, and s is the decimal value of the binary information to be embedded.

[0049] (2) Verification and Restructuring Phase

[0050] The steps for authentication and image reconstruction using this method are: participant authentication and reconstruction of the secret image.

[0051] (2.1) Authentication of Participants

[0052] Each participant can verify with each other whether the other is an honest participant.

[0053] In cases involving a credible third party, participant P i Submit your own verification share S' A C i A trusted third party can obtain a reconstructed verification image S' by performing the following operation on it and its own verification share D. A Based on the characteristics of RGVSS (Random Grid based Visual Secret Sharing), S' can be directly observed with the naked eye. A and S A Whether the two images are identical can directly determine whether the verification process can be passed. If the verification result is false, the share is recorded as... A trusted third party will participate in party P i Submitted secret share The broadcast was sent to all participants.

[0054] In the absence of a trusted third party, participant P i and participating party P q Each of them will give their secret share S' A C i and S' A C q Send it to the recipient, and then use the following formula to decrypt the encrypted data. If the reconstructed verification image S' A With S A If they appear identical to the naked eye, then the verification process passes; otherwise, the share is recorded as... And broadcast it immediately to all participants.

[0055]

[0056] (2.2) Reconstructing the secret image

[0057] Authenticated participants can submit their share of secret images, S'C. iWhen the number of submitted secret shares reaches k or more, the secret image S' is reconstructed using the following formula.

[0058]

[0059] Example 2: Implementation method of the present invention in a face recognition scenario

[0060] like Figure 2 As shown, the secret image sharing scheme for face recognition in this embodiment has two parts in its design process: face data acquisition, uploading and storage, and face data recovery and recognition.

[0061] (1) Facial data collection, uploading and storage

[0062] The information collection department collects facial image data of customers with different access levels in the system using cameras, then uploads it to a central server. System administrators then process the complete image data on the central server using methods such as... Figure 2 The generation and embedding functions in the transform domain-based reversible image secret sharing method shown perform face data segmentation and steganography, and then distribute the data to n different sub-servers to complete distributed storage.

[0063] (2) Face data recovery and recognition

[0064] When facial verification is required, the image acquisition department first captures the user's face in real time, then uploads the image to the central server, which immediately uses it as follows: Figure 1 The verification and reconstruction functions of the transform domain-based reversible image secret sharing method shown collect multiple shares stored from each server; then, the reconstructed face image is matched and identified with the real-time acquired face image. If the matching results are consistent, the user's permission request is granted.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for reversible image secret sharing based on the transform domain, characterized in that: The design process of this method includes at least two phases: 1) the generation and embedding phase; 2) Verification and Restructuring Phase; The steps for generating and embedding secret shares using this method include at least: generating secret shares corresponding to an initial secret image and a verification image; and embedding the secret shares. The generation of the secret share corresponding to the initial secret image and the verification image includes one or a combination of the following steps: A secret image S is encrypted using a (k,n) secret sharing scheme based on Lagrange polynomials, generating n encrypted images. ; A (2,2) visual secret sharing scheme based on random grids is used to analyze a verification image. Encryption is performed to generate two secret shares. Firstly, for The pixel value is randomly selected from 0 and 1, and then the corresponding value is generated using the following formula. : Then, the generated and The assignments are randomly distributed among the participating parties and trusted third parties who may be absent. The secret share embedding is a technique used to embed verification shares and secret shares into different channels of a color carrier image through discrete wavelet transform, singular value decomposition, and improved LSB technology, thereby achieving steganography of secret image data.

2. The reversible image secret sharing method based on the transform domain according to claim 1, characterized in that: The authentication and image reconstruction using this method includes at least the following steps: 1) Authentication of the participants; 2) Reconstruction of the secret image.

3. The reversible image secret sharing method based on the transform domain according to claim 2, characterized in that: The participant authentication process includes at least one or a combination of the following steps: Each participant can verify with each other whether the other is an honest participant; In cases involving a credible third party, the participating parties Submit your own verification share A trusted third party can decrypt the image along with its own verification share D to obtain a reconstructed verification image. ; observed directly with the naked eye and If the two images are identical, the verification process is passed; otherwise, the share is recorded as [missing information]. Trusted third parties will participate Submitted secret share The broadcast was sent to all participating parties; In cases where no trusted third party is involved, the participating parties and participating parties Each of them will hold their secret shares and Send it to the other party, and then each party decrypts the encrypted data; if the reconstructed verification image... and If they appear identical to the naked eye, then the verification process passes; otherwise, the share is recorded as... And immediately broadcast it to all participants.

4. The reversible image secret sharing method based on the transform domain according to claim 3, characterized in that: The reconstruction of the secret image includes: authenticated participants can submit their share of the secret image. Once the number of submitted secret shares reaches k or more, the secret image is reconstructed. .

5. The reversible image secret sharing method based on the transform domain according to claim 1, characterized in that: Each participant does not use additional bits for encryption and is allowed to complete the authentication process without the involvement of a trusted third party.

6. The reversible image secret sharing method based on the transform domain according to claim 1, characterized in that: This method completes data transmission in the transform domain and data sharing in the ciphertext domain.

7. The application of the transform domain-based reversible image secret sharing method according to any one of claims 1-6 in face recognition, characterized in that: Applying a transform-domain-based invertible image secret sharing method to face recognition involves at least two stages: 1) face data acquisition, uploading, and storage; 2) Face data recovery and recognition; The steps of facial data collection, uploading, and storage include at least: capturing facial image data with a camera; generating an initial secret image and a secret share corresponding to a verification image based on the facial image data and personal information; and embedding the secret share. The steps for facial data recovery and recognition include at least: identity verification, secret image reconstruction, and facial recognition.

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