Research On Image Tamper-proof Encryption Method Based On Blockchain

As an important carrier of multimedia communication,digital image plays an important role in communication,medical treatment,military and so on.In order to avoid the privacy disclosure of image data,image encryption technology plays an important role in national security protection,commercial interest protection and personal privacy maintenance.However,encrypted image data information still exists security risks such as malicious attack,tampering,copying or malicious use.Blockchain technology is widely used in the field of image security by virtue of security features such as tamper-resistant,transparent and distributed,but the technical challenges from performance,cost,expansion and other service quality and privacy security are becoming more severe.Therefore,this thesis mainly aims at the problems that existing image encryption methods cannot effectively resist differential attacks,low security and privacy,easy to tamper and abuse,not easy to resist geometric attacks and other threats,as well as low efficiency of encryption and decryption.By using the security characteristics of blockchain,this thesis studies the key technologies such as image tamper-proof encryption based on blockchain.The main research work is as follows:1.In order to solve the problems that existing image encryption methods cannot effectively resist differential attacks,have weak robustness,low security and privacy,and are easy to tamper with,an image tamper-proof encryption scheme based on blockchain and Lorenz hyperchaos S box is proposed.Firstly,the plaintext pixel value of the original image is extracted,and a round diffusion is realized by XOR with Lorenz hyperchaotic sequence.Then Lorenz hyperchaotic S-box is used to carry out two-round diffusion of the pixel values after diffusion to complete the image encryption,and the encrypted image is converted into a 256-bit ciphertext image hash code.Finally,intelligent contract is used to complete the IPFS storage of ciphertext image hash code and anti-tamper detection.The experimental results show that,compared with the existing scheme,the scheme not only ensures the security of image data transmission process through the on-chain and on-chain anti-tamper mechanism,so that the attacker cannot get accurate original image through the encryption hash,but also realizes the automatic security storage of ciphertext image information and tamper detection through the intelligent contract.2.In order to ensure the security of image data in applications such as image sharing,transmission and trading,realize traceability and tamper detection of image transactions of authorized users,and improve the security,encryption and decryption efficiency,robustness and other performance of image encryption algorithms,a traceable image tamper-proof encryption scheme based on block chain and homomorphic encryption is proposed.Firstly,Paillier algorithm and block encryption technology were used to encrypt the image.After extracting the feature image from the encrypted image by means of lifting wavelet transform(LWT)and singular value decomposition(SVD),zero-watermark images were generated after scrambling,diffusion and x OR of binary watermark information by dynamic S-box,thus realizing lossless embedding of traceability information.Then the zero-watermark image and its key are saved to the International File system(IPFS)by intelligent contract to control the image transaction,so as to realize the image traceability.Finally,the intelligent contract is used to detect the inaccurate bit and bit error rate of the zero-watermarking image to realize the tamper detection.The experimental results show that the scheme can realize the private data distribution and calculation in ciphertext state,the encryption and decryption efficiency is high,and the zero-watermarking algorithm has strong anti-attack ability and robustness.The tamper detection and tracing of encrypted images are solved well while protecting the privacy of images and storing them safely.