John Doe / Strangeness of the Self

By thinking about what the "self" means we come out with an important question: how do we identify a person?  How are we coming to different characteristics and who or what determined our identity?
Via the culture, mentality and social interaction person gets identity.  But in the science is there the name for people without an identity: John Doe. These are people whose identities are lost in a certain way.
How gets John Doe a new identity? Our subjective consciousness switches on automatically when we want to identify someone. This method of identification has sincerity meaning but is always cheating.
What kind of identity gets John Doe if everyone takes him from his own subjective consciousness explained him? And who is John Doe?