Deployment of secure sharing: Authenticity and authorization using cryptography in cloud environment

Cloud computing is a cost-effective, scalable and flexible model of providing network services to a range of users including individual and business over the Internet. It has brought the revolution in the era of traditional method of storing and sharing of resources. It provides a variety of benefits to its users such as effective and efficient use of dynamically allocated shared resources, economics of scale, availability of resources etc. On the other part, cloud computing presents level of security risks because essential services are often controlled and handled by third party which makes it difficult to maintain data security and privacy and support data and service availability. Since cloud is a collection of machines called servers and all users´ data stored on these machines, it emerges the security issues of confidentiality, integrity and availability. Authentication and authorization for data access on cloud is more than a necessity. Our work attempts to overcome these security challenges. The proposed methodology provides more control of owner on the data stored on cloud by restricting the access to specific user for specific file with limited privileges and for limited time period on the basis of secret key using symmetric as well as asymmetric mechanism. The integrity and confidentiality of data is ensured doubly by not only encrypting the secret key but also to the access permission and limited file information.