WordNet records no synonym and no antonym for positive identification. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
evidence proving that you are who you say you are; evidence establishing that you are among the group of people already known to the system; recognition by the system leads to acceptance
“a system for positive identification can prevent the use of a single identity by several people”
Synonyms, antonyms and the broader and narrower relations for positive identification come from Princeton University’s WordNet. Full sources and licences.