I am an Android and Web Developer and I worked with my mate which has holding all the customers and receiving the money, deadlines and that stuff.
When finished these apps, he didn't want to pay me anything but I have proof on emails and SMS where he said he was going to pay me.
I have never signed any document where I declare that I give all my projects to him, so on Android part I have keystores, Google Accounts for APIs (Google Maps, Analytics) and sources.
What would be my "technologic weapons" if I have to go to legal with him?