I'm not going to tell a friend my salary
Why don't you want to tell them your salary?
I don't like telling people what I make at work. It's not any of their business.
It's perfectly fine to keep your salary private. That is YOUR business.
I refuse to give them my salary information.
That is fine to keep that information private, the law says it is your right and you have no obligation. Your employer can't make you either, so keep it between who you choose.