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!

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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)