SECURE CLOUD DATA SHARING BY AGGREGATION OF KEYS INTO A SINGLE DECRYPTION KEY

Abstract

Cloud computing offers a number of advantages to all type of users including end users and business enterprises. It is a technology which allows the users to get access of applications and resources from anywhere which are not residing in our computer, but residing in some other locations. The problems in cloud computing are regarding the security of stored data as well as the shared data. To protect one's data over cloud, the basic techniques used include encryption, authentication and authorization which are becoming less efficient these days. Security and privacy issues get even worse when a set of particular data needs to be shared with specific users. Traditionally there are two main methods to share a set of selected data with another particular user. Either encrypt all data with single key and give the corresponding single decryption key to the other party, or encrypt each data with distinct keys and send corresponding keys to the receiver. In the first method, all the data will be leaked to the receiver. Obviously, the second method is inefficient since transferring and storing all the keys require large space. In this project, a set of data, called the ciphertext class is being shared with a particular user or group of users, as per the data owner's requirement. A single, compact, but powerful key is used as decryption key which is generated using a combination of different cryptographic algorithms as well as the ciphertext class identifier. The user who is receiving the ciphertext class will be able to decrypt it only if he is the indented user and he possesses the powerful decryption key. Hadoop framework is used for providing the distributed cloud environment. The implemented project works well for files of different types and sizes which are shared to individual users as well as groups of users. The results show that there is not much time difference for different types of files for encryption and uploading as well as for decryption and downloading.