Cloud computing is one of the emerging technologies where resources are provided on pay as you go basis. It is an efficient solution for the fast storage and retrieval of data. It is more than simple internet. The main concepts of cloud computing are confidentiality, integrity, availability, authenticity and privacy. The main issues to be concerned about the growth of cloud are security and privacy. It is important to preserve the data, as well as, privacy of users. One of the factors to preserve data is access control. Access control provides privileges to users on their data and protects it from unauthorised users. Access control is widely used in the medical field in which the access to patient's record is granted only to the scheduler and the concerned doctor. In simpler words, access control is the prevention of unauthorised use of resource. Confidentiality and efficiency must be maintained when access control is given for the system resources. So a number of algorithms are introduced and are implemented in the access control methods. This paper deals with one of the access control mechanisms and the algorithm implemented in it.

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Security Privacy Access Control Cp-abe Bit Exchange Method.