Question [Q] Cloud Computing

Hi All,

Question 1:
I have developed Android App for school for which I have use the following technologies and I am new to Android development.
UI - Android
Back end - MYSql and Java.
Used REST API to communicate.
1) I am confused how to implement the above in Cloud Environment. Can some help me to implement this in cloud environment. In future I want support to iOS and Windows
2) How to make my communication secured (do i need to encrypt).
3) Whether I have use wrong technologies and it is not possible to implement this cloud environment.
4) How to implement push notification

For all the above any standard open source SDKs available which i can use? If available what are the different SDKs available and which is the best one to use.

If the above information is not clear, please let me know.