  Quick UDP Internet Connection (QUIC) is an emerging end-to-end encrypted,
transport-layer protocol, which has been increasingly adopted by popular web
services to improve communication security and quality of experience (QoE)
towards end-users. However, this tendency makes the traffic analysis more
challenging, given the limited information in the QUIC packet header and full
encryption on the payload. To address this challenge, a novel rule-based
approach is proposed to estimate the application-level traffic attributes
without decrypting QUIC packets. Based on the size, timing, and direction
information, our proposed algorithm analyzes the associated network traffic to
infer the identity of each HTTP request and response pair, as well as the
multiplexing feature in each QUIC connection. The inferred HTTP attributes can
be used to evaluate the QoE of application-layer services and identify the
service categories for traffic classification in the encrypted QUIC
connections.
