Achieving Constant-Size Aggregate Key for Efficient and Secured Data Sharing

Cloud computing is a technology which maintains the data and applications using the internet and central remote servers. Cloud computing allows consumer and businesses to use applications without any installation by using the internet they will access their personal files on any computer. Cloud storage is a service model in which data are maintained, managed and backed up remotely and made available to users over a network. Cloud storage can provide better accessibility, and reliability, strong protection, disaster recovery and lower cost. In proposing method a new public-key encryption is introduced which is called as Key-aggregate cryptosystem (KAC). Key-aggregate cryptosystem turn out constant size ciphertexts specified economical delegation of decoding rights for any set of ciphertext area unit attainable. Any set of secret keys can be aggregated and make them as single key, which holds the power of all the keys being aggregated. This aggregate key can be sent to the others via secured channels for decryption of ciphertext set and remaining encrypted files outside the set are remains confidential.