What you are referring to is a "stop and identify law" that would require you to identify your self to the police. It is my understanding that Oklahoma does not have such a law. And there is no law that requires you carry identification unless it is a law associated with say driving a car (you are required to carry your license when operating a vehicle in every state). Now, if you are walking along and a cop stops you ask if you are being detained.  If they say no then ask to leave.  If they say yes, ask to call a lawyer.