Key-aggregate cryptosystem for scalable data sharing in cloud storage

Data sharing is an important functionality in cloud storage. In this article, we show how to securely, efficiently, and flexibly share data with others in cloud storage. Here we introduce new public-key which is used to convert the readable data into unreadable format, such process is called Encryption. The process of converting of the unreadable data to readable format is called Decryption. The novelty is that one can aggregate any set of secret keys and make them as compact as a single key, but encompassing the power of all the keys being aggregated. Here we provide formal security analysis of our schemes in the standard model and also describe other application of our schemes. In particular, our schemes give the first public-key patient-controlled encryption for flexible hierarchy; the purpose of using the Public-Key is used to protect the data from unauthorised persons.