Cloud computing is an on-demand computing. It is an Internet-based computing. In this area shared resources, data and information are provided on demand to computers and other devices. It also provides the services over the internet. In cloud computing, service providers have ability to provide storage at server according to users need. They allow users to store and retrieve the data in cloud server on demand from anywhere and on any type of device. This manipulation of data at cloud server

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... s rise to so many security issues because data is accessed over internet. For security purpose data is store in encrypted format. In this, client has no direct control on data once it is uploaded on cloud server. In this paper, we investigate the idea behind single keyword search over encrypted data and also multi keyword ranking. Cloud data owners want their documents in an encrypted form for the purpose of privacy preserving. Therefore it is necessary to develop efficient and reliable ciphertext search techniques. One challenge is that the relationship between documents will be normally concealed in the process of encryption, which will lead to significant search accuracy performance degradation.