Cloud is a type of platform which helps to store the data as well as helps in sharing the data. While sharing the huge amount of data, the primary concern comes in mind is data integrity, security of the data. For the cloud server and the user it is not possible to check the integrity, consistency of stored data on cloud. Public Auditing method can help to overcome this problem. Hence the user takes help of the third party auditor (TPA) for auditing their data. Many of the techniques have been proposed by various researchers which improve upon one another. Here we have presented three landmark methodologies on Privacy preserving cloud auditing for shared data on cloud.