Abstract: Data sharing being important functionality in cloud storage implements how to securely, efficiently, and flexibly share data with others. The public-key cryptosystems produce constant size cipher texts that efficiently delegate the decryption rights for any set of cipher texts. The significance is that one can total any arrangement of mystery keys and make them as conservative as a solitary key, yet including the energy of all the keys being accumulated. The mystery key holder can discharge a consistent size total key for adaptable decisions of figure content set in distributed storage; however the other encoded documents outside the set stay secret. The total key can be advantageously sent to others or be put away in a brilliant card with exceptionally restricted secure stockpiling.

Keywords: Cloud storage, public key encryption, cryptosystem, key aggregate encryption, and key aggregate cryptosystem.