The best security: be honest and place complete trust in those you employ. Hire people you trust. If there is nothing that is blocking you, then morale is higher, and people get more focused on what is important. If there is nothing to break into, there is less temptation. Your employees won't be perfect, but if they are trusted, if you let things be, there's a good chance everything will be fine- at least as fine as it would have otherwise.