Secure and Scalable Data Sharing in Cloud Storage using Key-Aggregate Cryptosystem Technique

Abstract

Sharing of Data is an main functionality in cloud Computing. In this system, we show how to share data in securely, flexibly, efficiently, and with others in cloud computing. We design new public-key cryptosystems which produce Fixed-size encrypted texts such that efficient delegation of decryption rights for any set of Encrypted data are possible. The innovation is that one can aggregate any set of secret keys and make them as compressed as a single key, but on all sides of the power of all the keys being aggregated. In other words, the secret key holder can release a fixed-size aggregate key for flexible choices of encrypted text set in cloud storage space, but the other ciphered files outside the set remain secret. This compress aggregate key can be conveniently sent to others or be stored in a E-mail with very limited secure storage space. We provide formal security analysis of our system in the standard model. We  also describe other application of our schemes