also
they can be a legal fiction
AND
a proxy for authenticity
those statements are not mutually exclusive.
I'm just suggesting state violence isn't a preferable solution to the problem of ensuring authenticity.
Discussion
Certification will exist in the absence of a state. Impersonation is a contract law breach, and contract disputes always need adjudicators. The state weakens impartiality but does not change the material facts of a case.