Cloud computing is a new technology in the market. In cloud computing user can access their files or data from anyplace using internet. There are several benefits of cloud computing like increase throughput, reduce costs, improve accessibility and requires less training but on the other hand it has some security issues. In that, identifying authorized user is a major issue. The user wanting to access the data or services needs to be registered and before every access to data or services; the user identity must be authenticated for authorization.