Now-a-days, cloud computing is become more popular as cloud infrastructure provide storage facilities for data owners. Data owner stored their data on public cloud for convenience high availability, easy accessibility and reduced cost in data management. Clouds storage allows users to store data and can be access anywhere, any time by using any technology. Sensitive information such as business related documents, medical records and product information may be stored in a cloud. As sensitive data are encrypted before outsourcing to cloud, traditional keyword search techniques are useless. Security and privacy are becoming challenging for cloud infrastructure.