If a breeder requires my social security number or driver's license number to get a puppy, I'll RUN away--not walk. I am willing to give addresses, phone numbers, answer numerous questions, provide references and more. But while I love dogs, I have yet to see a puppy worth risking my identify, financial assets and credit security for.
The only places I give that info to are trustworthy places that legitimately need it. For example, businesses or organizations that keep their numbers stored and are prepared for accepting the responsibility and liability of having such things.
But an individual? No way in heck. And the thought that an individual breeder would potentially have the social security numbers of numerous people is very frightening to me. What if they're visited by a not-so-savory relative who goes through the files? What if they're robbed? Or what if they just have a moment of carelessness, and accidentally throw an unshredded copy of that info into the trash?
Breeders have been placing puppies responsibly for decades without needing such personal info. But if that's the trend that breeders are going towards, I guess I'm going to stick with found strays like Voodoo, or rescues that don't require that info.