Abstract: Data sharing is an important functionality in cloud storage for searchable encryption. In this paper, we describe how to securely, efficiently and flexibly share data over multi users in cloud storage. We developed a secret key for multi users which are group key and normal single key. We describe group key as a constant-size ciphertexts. Such that efficient delegation of decryption rights for any set of ciphertexts are possible. In other words, the secret key holder can release a constant-size aggregate key for flexible choices of ciphertext set in cloud storage, but the other encrypted files outside the set remain confidential. We provide formal security analysis of our schemes in the standard model. In this paper, we developed AES algorithm for secret key generation. In which a data owner only needs to distribute a group key and normal single key for each file or more than one file to the user for data privacy purpose.

Keywords: Data Sharing, Searchable Encryption, Group Key, Data Privacy, cloud storage.