In this paper a RSA based security system enabling the group of users to upload the single masked message to the cloud environment is proposed. Data stored are encrypted using RSA algorithm. The data receiver is able to encrypt the message retrieved from the cloud environment using private key. Two different separate RSA systems are used. The presented approach is divided into three parts. First, an RSA key is generated for each sender. Then masking the message by newly chosen mask proposed individually by every member, additionally encrypted by individual RSA private key of each member is proceed. Next, encrypting the gathered message inside the cloud environment, using the public key of the receiver is executed. In the third step, the message is decrypted by the receiver using his private RSA key. The scheme reduces the computational load on users side and transfers calculations and storage effort to the cloud environment. The proposed algorithm was developed for storing and sending the data that originally are produced by a group of users, but the receiver of the data is single. It was implemented using Java 8 and OpenStack software. Numerical test of different key length for RSA are presented