Privacy Preserved Data Retrieval Over Encrypted Data

Cloud Computing is growing up technology in current era,we can say it is being used widely in our daily life and it has become essential part of the world.Cloud computing provides us to online access of computational and network resources by using internet.Cloud services offer us to low cost and provide large amount of storage for data to attract end users on cloud.One of the most popular and worldwide service is called data outsourcing.It is convenient and low cast way for public and private organizations as well to outsource their date,they enjoy the advantages of remote storage and management,file sharing,back-up servers,email platform etc.In daily life,files storage is one of the common uses of cloud.At the same time concern is that to store important and sensitive data on un-trusted cloud server.For this concern we always use encryption scheme to encrypt sensitive information to outsource.A casual way to download the data,decrypting and searching our demanded data locally is not the efficient and meaningless when we store our important information on cloud.Cloud servers must enable searching scheme to retrieve encrypted data without unauthentic users because we cannot depend on severs own security,users don't want to take risk on their sensitive data.In this dissertation,we will discuss about retrieval encryption schemes from encrypted data by multi-users.Data retrieval from cloud by using ranked search,keyword search and hierarchical index search,However,traditional searchable encryption techniques use Boolean search to search data via keywords,but this technique does not satisfy the effective data utilization for multi users data need and also to retrieved big data files from cloud.It has been proposed index techniques where we can allocate the sequence on the cloud and encrypt it when it is outsourced but they have not ability to keep in order preserving-position when users fetch the ciphertext from the cloud.This problem is solved by using ranked keyword search over the encrypted cloud data,which improves system usability and files retrieval accuracy and help to protect the score information,one-to-many,order-preserving mapping technique has developed and explored the relevance score,from information retrieval to build a secure searchable index.Users will be verified by secret key when they will try to access the cloud data,after authentication they are allowed and they are authorized users.We will also check the keyword and hierarchical index search schemes.We will present the results of this area and comparison of existing searchable encryption schemes and their advantages and drawbacks.