Research On Plaintext Image Encryption And Distributed Secure Storage

After entering the multimedia era,people begin to transfer information,store data and share data through the network.Cloud platform provides a large amount of cloud space to store multimedia data such as text,image,audio and video,so as to solve the problems of limited computing power and insufficient storage space of a single computer.With the expansion of social network users,multimedia data began to show an explosive growth trend.However,after they are uploaded to the server or stored in the cloud,they will be completely separated from the protection of the sender.Therefore,when storing data in an unreliable cloud environment,how to ensure that privacy is not leaked has become a challenge.At this point,encryption methods are often used to ensure that the content of the data uploaded to the cloud server is not leaked.The existing encryption methods usually encrypt the plain image into a cipher-text image without visual meaning and then transmit it,but it is easier to attract the attention of attackers.And the multiplication of transmission bandwidth also brings huge burden to network transmission and storage.In addition,encrypted images are often stored on a single server in the cloud,and the data may be lost in the event of a malicious attack on the server.Therefore,in order to improve the security of the sender image and protect its privacy information from being leaked,this thesis proposes plaintext image encryption and distributed secure storage.The details of the research content and innovation are described as follows:1.A plaintext image encryption method based on lossless compression is proposedIn order to reduce the possibility of attack,the encrypted image is in the plaintext state after being uploaded to the cloud.This thesis proposes a plaintext image encryption algorithm based on lossless compression.Through the proposed encryption scheme,the sender encrypts and compresses the plain image into marked encrypted image with plaintext appearance,and then uploads the marked encrypted image to a semi honest and trusted cloud server.After downloading the marked encrypted image,the fully authorized receiver can decrypt it into the plain image.In addition,even if the marked encrypted image is attacked by an attacker in the cloud server,the final decrypted image is still readable.Experimental results show that the proposed method is not only completely reversible,but also can hide the large plain image into the small cover image,and is superior to other schemes in terms of visual quality and anti-attack performance.2.A distributed secure storage method based on encrypted image is proposedIn order to solve the problem that encrypted images stored on a single server will be completely destroyed after a malicious attack on the server,as well as for privacy protection concerns.This thesis proposes a distributed secure storage method based on encrypted image.First,the plain image is encrypted,and the encrypted image and privacy information are respectively shared into n shares by the ,9)threshold secret sharing algorithm.Then,the marked encrypted image shares can be obtained by reversibly embedding the private information shares into the encrypted image shares.Finally,they are sent to multiple servers for distributed storage.After collecting at least t shares,the receiver can merge and restore the plain image and privacy information,which greatly improves the security of the plain image storage and effectively protects the privacy information of the sender.Experimental results show that the proposed scheme is superior to other schemes in terms of encryption performance,embedding capacity and visual quality of decrypted images.