Cloud computing can be defined as a new style of Computing in which the resources are provided online through the internet. Cloud storage services allow the users to outsource their data in the cloud storage servers and retrieve them whenever and wherever required. This avoids the cost of building and maintaining their own data store. But the users need to provide privacy for the data and also needs to be able to search it without losing privacy. The users always search their documents through keyword in plaintext, which may leak privacy of users in cloud storage environment. So allowing a Cloud Service Provider (CSP), whose purpose is mainly for making a profit, to take the custody of sensitive data, raises underlying security and privacy issues.