Efficient Data Sharing in Cloud Medium with Key Aggregate Cryptosystem

In Cloud Storage there is an important functionality called Data Sharing, but the query always present in every ones mind is how to securely, efficiently, and flexibly share data with others in cloud storage. A new public-key cryptosystem is introduced to produce a constant size cipher texts such that efficient allocation of decryption rights for any set of cipher texts are possible. The uniqueness is that one can aggregate any set of secret keys and make them as compact as a single key, but surrounding the power of all the keys being aggregated. In supplementary terminology, the secret key owner can release a constant size aggregate key for flexible choices of cipher text set in cloud storage, but the other encrypted files outside the set remain private. This packed together aggregate key can be suitably sent to others or be stored in owners end to make the process more secure. Once the key is used by the owner then the formal key system change the key aggregate strategies and generates a new key for the data decryption, so that the user can access the remote resource with the help of generated key aggregate at single time only after that a new key will be generated for further use. In particular, this approach gives the first public key patient controlled encryption for flexible hierarchy, which was yet to be known.