Cloud computing contains groups of remote servers and software networks that involve in allowing storage of data and accessing of online computer resources. Cloud contains data storage to the huge amount of data. Cloud user should be concerned with the correctness and protection of data. When user outsources remote data from storage of data as a cloud, there is several auditing mechanism to verify the integrity of data. Public auditing mechanism enables the user to verify integrity of data with the help of Third Party Auditor (TPA). Public auditing mechanism starts auditing task by not downloading whole file.