How to organize work in a team so that the sources are not stolen?

Question

Programming

I brought my project to the prototype stage and I need to put together a small team to bring it to release. I need an intelligent designer and other people for the graph component.
Perhaps, but God forbid, of course, you will need the help of a programmer.
I need advice, is it worth giving the source code of the project? Let's do it if asked. If not, how to develop. I think it will be inconvenient for a designer to work blindly, because he needs to immediately check the design into action.
The engine I'm using is UnrealEngine4.7.6
I forgot to tell you what I'm afraid of. I'm not greedy, but suddenly someone turns around and leaves 99%, and then puts the product in the AppStore. And then I have to run and unsuccessfully prove who threw whom.

Answer 1

NDA? https://en.wikipedia.org/wiki/%D0%A1%D0%BE%D0%B3%D...

Answer 2

You can take nails and nail his feet to the floor so that he doesn't leave. And put him behind a laptop where access to the applestore is blocked.
You can kidnap his dog as insurance.
But the easiest way is not to give him the source code or give it partially, in addition to this, sign the contract from the first post.

Answer 3

1. NDA.
2. Separation into modules with the creation of convenient interfaces between components and the issuance of independent modules for development / improvement.

Answer 4

No one ever hijacks the source code in order to "put it in the appstore". Do you have a legal entity? Well, that's all. NDA, and at least distribute it to everyone.

Answer 5

Well, if you pay for the work and don't cheat, then they won't steal anything.