Secure data storage in cloud computing to avoiding some cipher text attack

Abstract Nowadays, cloud computing has become popular for storage of data. Yet, flexibility and security are the significant parameters for better transmission. Sharing data with others may lead to security and flexibility issues. Key cryptosystem is a technique in which, decryption rights for a set of cipher texts are efficiently assigned. Key aggregation will be performed by the power of all keys, when they are aggregated. But the delegated keys or aggregate keys stored in the mobile device are prompt to leakage. Hence, we need to design a leakage-resilient cryptosystem which reduces key leakage attacks. For leakage-resilient cryptosystem, we propose Hash-Proof System techniques; which will be applied on chosen cipher text key leakages and other key leakages. A number of cipher text classes are predefined in our approach.