WordNet records no synonym and no antonym for negative 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 not who you say you are not; evidence establishing that you are not among a group of people already known to the system; recognition by the system leads to rejection
“a system for negative identification can prevent the use of multiple identities by a single person”
Synonyms, antonyms and the broader and narrower relations for negative identification come from Princeton University’s WordNet. Full sources and licences.