One of the first few things we learned about him was that a clause in his contract forbid him from discussing our salaries and working conditions with us.
Long story short, I switched jobs shortly after because we were doing a lot of unpaid overtime, and tons of things that had nothing to do with a software developer's job.
But the straw that broke the camel's back was that we found out every engineer had a different contract -different salary, bonuses, etc.-, even when we had similar experience. The director's boss thought we wouldn't find out just because of that silly clause.
If you are being asked not to discuss your salary, apply Occam's razor, and either deal with it or run away.