Research Of Secure Nearest Neighbor Query Technology With Multiple Keys In Cloud

As the flourish of the cloud computing,enterprises and individuals are increasingly tending to outsource the storage or computation tasks to the cloud.The cloud computing makes enterprises and individuals freed from the labor of complicated construction and maintenance of infrastructure,and concentrate more on their core business.But for the moment the cloud computing faces many tough problems,and above all,security problem.In recent years,it has appeared a lot of studies about data security and privacy preserving in the cloud.On one hand,data owners encrypt the sensitive data(e.g.salary income,medical information,personal photos and so on)before uploading it to the cloud for security reasons.On the other hand data owners also hope to count on the cloud to do the data retrieval,not just provide basic storage services.Therefore,secure query technology for the encrypted cloud data is a hotspot in the recent research.Nearest neighbor queries are fundamental in spatial databases and multimedia databases,and secure nearest neighbor queries mainly focus on how to securely and quickly retrieve the nearest neighbor in the outsourced cloud server.Recently,various secure nearest neighbor query schemes are proposed to counter the security and privacy threat.Data owners usually encrypt data and then upload it to the cloud,after that,the authorized query users accomplish retrieval tasks by a complex set of encryption and decryption operations.However,the most existing solutions are based on the key-sharing model,That is,the query users are assumed to be fully trusted and can access all the keys of data owners.It is unrealistic,because if each user holds all the secret keys,the compromise of any user will result in the exposure of secret keys,and the security risk is further up due to the wide distribution of query users.In addition,a large majority of applications do not typically give complete trusts to the query users,which limited the scope of existing secure nearest neighbor query schemes.In a word,these schemes are far from being usable.In order to solve the above security problems of the secure-nearest-neighbor query in the key-sharing model,we present the secure nearest neighbor query scheme with multiple keys.In this multiple-key model,each query user holds the unrelated key and data owners also use their own keys to encrypt data while sharing them with others.We achieve two secure-nearest-neighbor query schemes in the multiple-key model based on the trusted proxy server and multiple clouds,respectively.The main content of research has the following respects.Firstly,we describe the secure query problem in the cloud and introduce a variety of existing secure query schemes.In addition,we mainly discuss the secure-nearest-neighbor query schemes,analyzes their respective advantages and disadvantages,and then present our basic ideas.Secondly,we design a secure-nearest-neighbor query scheme with multiple keys by utilizing the architecture of public cloud and proxy server.We present a set of secure two-party computation protocols for this architecture,which can protect the confidentiality of sensitive data and provide an efficient query method for the specified users.Specifically,a trusted proxy server is introduced to assist with computation tasks of users.And we also introduce a trusted authority to undertake the task of key management,which can break down the tasks and activities of the cloud server and the proxy server.The trusted authority is put in charge of the most significant work of key management.Therefore,the cloud server cannot obtain the information about all the keys(i.e.,the security of the whole system would not be destroyed),even though the cloud server colluded with the proxy server.Thirdly,in order to accommodate a more realistic solution,we design a secure-nearest-neighbor query scheme based on the multiple-cloud model.There are multiple semi-honest cloud servers in this model,they faithfully execute the protocols,but try to spy on private information of others participants.We construct a multiple-cloud modell by introducing multiple computation servers.In this model,we combine a distributed two trapdoors public-key cryptosystem(PCDD)and Yao's protocol to construct a mixed protocol for supporting secure-nearest-neighbor query with multiple keys.Our scheme not only preserves the data confidentiality and query privacy but also improves the query performance.Finally,we analyze and summarize the secure-nearest-neighbor query problem in the multiple-key model,and then point out the next step in the direction of work.