I am new to mobile app Development. For mobile push notification using SNS, we need to add device to SNS topic. One way is to directly make a call from the mobile app to amazon SNS.I need to send amazon aws_access_key_id and aws_secret_access_key with the request to register device to the topic which seems less secure. Alternate way is to send the device id to backend server and add device from backend. What is standard way to achieve this. I am unable to find relevant codebase and tutorials that explains it..