how to secure keys for API calls from android device to amazon services

so i am writing an app for android which will push some data over to Amazon S开发者_如何学Python3 storage to be later read. I am using Amazons SDK to make my calls but this requires me to store the public and private keys within my app. Is there a way to secure them so they couldn't be extracted by reverse engineering? Is it even possible since i will be making direct calls from the device? Or is my only option to run a proxy server (on EC2) and pass my data through it?

thanks for your help!

Step 1. Use HTTPS Step 2. AES encrypt the keys in the application

Other than that, there's not much you can do, other than using a proxy server (option you mentioned)