1. No comment.
2. I'm not at liberty to say. (= I don't have permission to give the information)
3. Wait and see. (= you will discover the answer later)
4. Let me get back to you. (= I will give you the answer later)
5. I'm sorry, that's confidential.
6. I'm sorry, that's personal.
7. I'd rather not talk about it.
8. It's none of your business.
9. Mind your own business.
10. Why do you want to know?
#8 and #9 are rather rude – telling the other person to stop inquiring about your life

Fact
Only two people signed the Declaration of Independence on July 4th, John Hancock and Charles Thomson. Most of the rest signed on August 2, but the last signature wasn't added until 5 years later.      .. More >>