3D Model Based On Digital Watermarking And Secret Sharing Copyright Protection Technology Research

With the wide application of 3D printing technology,3D models have been used in aerospace,industrial manufacturing,medical treatment and other fields.However,the data information content of 3D model is easy to be copied and tampered with,and the copyright cannot be effectively protected.At the same time,the rapid spread of the Internet makes the data of 3D models more easily to be copied and transmitted.The copyright protection and information protection of 3D models are becoming increasingly severe.The creators and owners of models are also in urgent need of technology and means to effectively protect the copyright.As an important research direction of information security,digital watermarking and encryption technology is an important means to realize the security of copyright protection and watermarking system.It is of great practical significance to study the copyright protection technology of digital watermarking and information sharing mechanism.In terms of the security of 3D model storage and transmission,if an intruder detects a security hole in the information storage where the protected model is located,he may try to decrypt the internal secret model,or simply destroy the entire information storage.Applying secret sharing is a secret defense against these problems.Thesis for 3D mesh model problem of copyright protection by embedding robustness of watermarking algorithm,through various common attack test to verify the robustness of watermarking algorithm,transparency,and finally the malicious attacks after testing by extracting the watermarking information in the3 D model of visibility,integrity,to show the feasibility of watermark algorithm,Thus,we can get the complete watermark information after the external malicious attack,which in turn shows that the watermark algorithm can achieve the function of copyright protection of 3D model.At the same time,using the principle that multiple people master secrets,that is,the secret sharing system as a protection tool,the research of 3D model secret sharing based on feature point selection is proposed.Through multi-person Shamir(k,n)secret sharing,the 3D model is shared to N participants as the secret model.Finally,Shamir secret restoration idea is used to reconstruct the original 3D model(key)lossless through K secret shadow models.The main research work includes:(1)From the point of protecting the copyright information of 3D model data,a 3D model blind watermarking method based on Logistic chaos encryption is proposed.The watermark information of the algorithm is generated from the lattice font,and a binary image of USTC 3D is obtained.The generated watermark image is processed by Arnold scrambling and chaos encryption.Then,the three-dimensional mesh model is displayed in multiple layers by using the method of mesh simplification,and the local set area of each vertex in the middle layer is calculated.Then the middle vertex with small and dense area is modified to embed the watermark information.Finally,the embedded watermark intensity is adaptive according to the curvature of the neighborhood of the vertex.Watermark detection is the opposite of watermark embedding.The experimental results show that the algorithm can resist the common attack methods,including noise,smoothing,mesh simplification,affine change and so on.It not only protects the copyright of 3D model,but also improves the security of digital watermarking system.(2)In view of the shortcomings existing in some traditional protection technologies,such as centralized storage,because the whole protected model is usually maintained in a single information store.In order to protect the storage and transmission security of 3D models,a secret sharing scheme of 3D models based on feature point selection is proposed.According to the degree of concave and convex of the vertices of the 3D model,the salient value of the 3D model is calculated and the salient feature points are selected.Shamir(k,n)threshold secret sharing generation scheme was used to divide the 3D model(secret)into k shadow shares and send them to n participants.Finally,at least k(k?n)new3D models are selected to extract the sub-feature points according to the serial number.According to the Shamir(k,n)threshold secret sharing restoration scheme,the 3D model,namely the secret model,is restored without damage through Lagrange calculation.Experimental results demonstrate the feasibility of the proposed scheme for model protection in different 3D models.(3)Develop and implement the 3D model digital watermarking secret sharing system.The system is based on the blind watermarking algorithm of 3D mesh model based on Logistic chaos encryption and the secret sharing mechanism of 3D model based on feature point selection,and adopts the object-oriented design method of C++ to realize seven functional modules: The encryption of watermark,the embedding function of digital watermark based on Logistic chaos encryption,the extraction function of digital watermark of 3D model,the visualization and interaction function of 3D model,the extraction function of feature points,the secret sharing function and the secret reconstruction function.The test results show that the system meets the functional requirements of the system requirements and achieves the desired purpose.In this thesis,the blind watermarking algorithm of 3D mesh model based on Logistic chaos encryption,the secret sharing research of 3D model based on feature point selection and the secret sharing system of 3D model digital watermarking are adopted to effectively solve the security of the watermarking system and the robustness of the watermarking algorithm.The watermark secret sharing system developed has certain application value and popularization value for the research of copyright protection of 3D model.