In Distributed systems, the users with a certain set of attributes can only be able to access the data. At present this process can be done through a trusted server where we will store the data and there will be certain constraints on the access of the data. In this case there will be a possibility to compromise the data and so the confidentiality of the data is lost. An Attribute-Based Encryption (ABE) is an encryption scheme, where users with some attributes can decrypt ciphertexts associated

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... with these attributes. Now this is our turn to develop a system with a more complex policy of access of the encrypted data and which can be called as Ciphertext Policy Attribute-based Encryption (CP-ABE). By using this method the information can't be traded off even through the trusted server where the information is put away. These methods are also secure against the collusion attack. In this method attributes are generally assigned in the form of access trees. The attributes are placed at the leaf nodes of this access tree. In older Attribute-based encryption strategies encrypted data is described by the attributes and policies are given to the user's keys, while in our system users credentials are described by the attributes and there will be a policy where it tells us about who should access or decrypt the data. So, this type of access method is very much closer to the Role-based attribute-based encryption.