  QUIC is a recent transport protocol that provides reliable, secure and quick
service on top of UDP in the internet. As QUIC is implemented in the
application space rather than in the operating system's kernel, it is more
efficient to dynamically develop and roll out. Currently, there are two
parallel specifications, one by Google and one by IETF, and there are a few
implementations. In this paper, we show how state machine inference can be
applied to automatically extract the state machine corresponding to the
protocol from an implementation. In particular, we infer the model of Google's
QUIC server. This is done using a black-box technique, making it usable on any
implementation of the protocol, regardless of, for example, the programming
language the code is written in or the system the QUIC server runs on. This
makes it a useful tool for testing and specification purposes, and to make
various (future) implementations more easily comparable.
