Widget logic by ip address

Hello to everyone,
I was looking forward to find a solution of showing some widget to everyone except to some user IP’s. So, if a visitor has IP 12.34.56.78, the widget will not appear. I have tried to add a function on my theme and then to use it on widget logic to do the verification, but i didn’t succeed. Hope that someone can help me on resolving this.
Thanks to everyone.