A Survey on Public Auditing With a Proof of Retrievability in Secure Cloud Storage

software as a service (SaaS), Infrastructure as a service (Iaas), storage as a service (STaaS), security as a service (SECaaS), Data as a service (DaaS) & many more. Out of this Paas, SaaS and IaaS are most popular. Cloud computing has four models as Public cloud: though which the service is available to all public use. Private cloud: Through which service is available to private enterprise or organization. Community Cloud: It allows us to share infrastructure among various organizations through which we can achieve security, compliance and jurisdiction. This can be managed internally or by a third-party and hosted internally or externally. Hybrid cloud: it is a combination of public and private cloud. Cloud computing has many advantages as: we can easily upload and download the data stored in the cloud without worrying about security. We can access the data from anywhere, any time on demand. Cost is low or pay per usage basis. Hardware and software resources are easily available without location independent. The major disadvantages of cloud computing is security.