Secure Third Party Auditor for Ensuring Data Integrity in Cloud Storage

Although cloud computing is extremely active over the Internet in the real world, it presents many security challenges, such as access control and data integrity, which refer to the fact that while users can deploy their files into the cloud server, no one knows exactly where they should be. Thus, users´ data may be threatened by internal or external attacks. Recently, some proposed schemes are aiming to find solutions to these problems which directly affect the data under the cloud. These are based on a Third Party Auditor (TPA) as one of the most popular solutions, where users no longer have physical possession of the possibly large size of their outsourced data, and they consider that the TPA should be able to efficiently audit the cloud data storage without demanding local copies of data, and they introduce no additional on-line burden to the cloud user. Unfortunately, these schemes have assumed that the TPA is a trusted party for users. In fact, this assumption is critical, because the security aspect hinders widespread adoption of the cloud. However, users cannot ensure that either the TPA or the cloud server (CS) will not be impersonated by an attacker. So, the cloud user should be the only person (data owner) who has confidentiality about his data. We offer a new TPA model that differs from previous models and overcomes the above-mentioned issues. Our proposed scheme has three main components: the cloud user (data owner), the TPA, and the cloud server (CS), where only the user has the authority for his data and he deals with other components as services. The proposal enjoys several advantages such as preserving privacy and session key secrecy. Our proposed scheme combines the two important features of both efficiency and security concerns: (1) TPA functionalities, (2) complete confidentiality at the user side. Furthermore, our work includes many security features such as secure and efficient use of the TPA for correct data storage with supporting data dynamics.