Cloud computing is one of the trending technologies in the present world. As cloud allows its users to pay for what they use, it has grown up large. These days mostly every big enterprise has its own cloud. As the number of users using the cloud is increasing day by day, there is a need for improving scalability. To overcome this problem inter cloud communication is suggested. Through this we can achieve scalability and a lot of users can be given space. During inter cloud communication, if both the clouds have different access control policies then there would be certain disturbances. This paper comes out with a new architecture which allows two clouds which have different architectures, role based access control (RBAC) and Discretionary access control (DAC) to share resources. This is implemented using an access matrix called 'Inter cloud access matrix' and 'access table' which helps in analyzing the access given to the user either with a single role or multiple roles. This paper also comes out with a new technique called 'colored roles', where each role is associated with a unique color.

There has been recently considerable interest in Role-Based Access Control (RBAC) as an alternative to traditional DAC and MAC access control schemes. The interest in RBAC is due to its simplicity in implementation, since it adapts to the working environment of any organization effortlessly. Every cloud computing resource subjects are categorically divided into the predefined roles and policies are defined for each role. Hence the RBAC is defined as a mapping between user to roles and the roles to privileges making the access control design simple, adaptable and easily implementable. DAC scheme provides complete control to the owner of the object on the decision of access control using access control matrix and list. The problem in the present RBAC scheme is that all subjects who are in same role can access the data specified for that particular role, but we can't specify data for any particular subject in a particular role. Our system combines the concept of ACL (Access Control List) & ACM (Access Control Matrix) of DAC with the RBAC to enhance the data integrity in RBAC. Thus to achieve this, we have to add ACL to all the objects (data) and ACM to all the objects (roles) in the system, this restricts other subjects of the same role from accessing one particular subject's data.Index Terms-RB-DAC, smart-card, access control matrix, access control list, MITM -man in the middle attack, 2014 3rd International Conference on Eco-friendly Computing and Communication Systems 978-1-4799-7002-5/14 $31.00