In these computational world security is the major Problem. Because the hackers are growing day by day. Here majorly attackers attacks mostly while sharing or sending the data. So here we are using PAAS i.e. windows azure as the storage which is one of the service in cloud. So to provide the security for the data here we come up with an RSA (encryption and decryption) algorithm. This is one of the security mechanism to protect the private data over the cloud.