ABSTRACT
Cloud data storage service is one of many services provided by cloud where the
data owner stores his/her data in the cloud and shares the data among group of
users with differential access rights. Many Organizations tend to enjoy the
convenience of cloud data storage service to offload the burden of storing and
managing their big data by outsourcing data to the cloud. However, storing data in
the cloud may be subject to many security issues as cloud cannot be fully trusted.
Once data is uploaded in the cloud, owner completely looses control over the data.
Due to virtualization of resource and complex distributed architecture of cloud, it
is really tough to determine where the data is physically located and how cloud
service provider is treating with the data. For example, cloud may leak
confidential organizational information or change part of the data for financial
incentives from other competitor companies or even hide any data loss caused by
software or hardware failure to avoid penalty. On the other hand, providing data
confidentiality in a dynamic group of users becomes really tough when it comes to
key management. That is why we have designed a secured cloud storage model
that ensures the confidentiality of data and empowers the owners to check integrity
and availability of their data at the same time. Our proposed solution also gives
better security than the existing solutions in a group user scenario.