The basic idea of the project is to share the data in the cloud. The dataset in the cloud storage is secured and more flexible to share the data with others. For that, we propose Key- Aggregate Cryptosystem which produces cipher text of a constant size such that decipherment rights are often assigned to them. By combining a collection of secret key, we will create a compact single key. By exploiting this compact key, we will send others very restricted secure storage. First, owner of the information sets up the general public system. Next Key information formula generates a public or master key. By exploiting this key, the user will convert plain text into cipher text. After that user can provide input as master secret key by an Extract function. It will manufacture output as mixture decipherment key. And this obtained secret key is safely sent to the receiver. Then the employment with the mixture key will decode the text of a cipher through the use of decode perform.