arxivcs.CRcs.CLcs.LG2026-07-11
One Token Is Enough: Fingerprinting and Verifying Large Language Models from Single-Token Output Distributions
Large language models (LLMs) are increasingly consumed through opaque serving chains - API aggregators, resellers, and inference providers - in which the client has no technical means to confirm that the model answering is the model advertised, and recent audits show that a subst…