Is there a PHP based authentication library?

Hi, I stumbled upon this payment library: http://ci-merchant.org/ which abstracts the different payment backends away and exposes a new easy to use interface for the app developer to use. Thus making it very easy to use different payment providers. I was wondering if something like that is also existing for authentication? For example, in authentication you have quite a few different ones: - Mozilla Persona - openid - facebook connect - google (openid?) - use/pass based authentication (a.k.a. the self made version that every dev begins with) - oauth - twitter connect - etc... Is there such a library in existence? I'm especially looking for one with mozilla persona implemented. Kind regards, Mark