I spent a hour to understand how to generate OAuth comsumer key for Google OAuth.
Here is the easiest way to do it.
step 1> Insert meta tag in your html and upload it server that is running.

step 2> after uploading the page, click verify. And then you'll see a page like this in you google master.

step 3> Generating keys using OpenSSL. I assume you're using OS X. Do this in your terminal
step4> Upload myrsacert.pem
