Cloud comes with lots of benefits but still users hesitate to adopt it. Still there are certain issues which are complications in the development of cloud computing. Most protuberant issue prevailing now-a-days is data security at cloud. Main reason or fear in user mind is regarding security whether their data is in insecure hands or is it safe to upload their sensitive data over cloud. To solve this problem of data security a models has been proposed. The authors' cloud security model plans to keep the most critical data security in cloud computing at different levels like user level, cloud service provider level, third party level and network intruder level.