We don’t store your data. Data that you backup are stored on Apple’s servers, in your personal iCloud.
MASTER HASH KEYS, WHICH YOU CAN SHARE ONLY IF YOU WANT, ARE NOT YOUR PRIVATE DATA.
PURPOSE OF SHARING MASTER KEYS IS ONLY TO HAVE MORE MASTER HASH KEYS AND TO EARN MORE POINTS
Purpose of sharing master keys is only to have more master hash keys and to earn more point.