That should be proof enough, then. Remove the device from their possession until they can produce the person intelligent enough to create it without your plans and can prove they are capable of doing so.

And if we are fighting for these people and this universe, I do not see how anyone who claims to be in any way good or fair could consider us fair game simply because we come from somewhere else. We risk our lives for them. One of our number has died for them. Why should they get the right to dredge up our secrets and tell them to the galaxy?