  The development of quantum networks is paramount towards practical and secure
communications. Quantum digital signatures (QDS) offer an
information-theoretically secure solution for ensuring data integrity,
authenticity, and non-repudiation, rapidly growing from proof-of-concept to
robust demonstrations. However, previous QDS systems relied on expensive and
bulky optical equipment, limiting large-scale deployment and reconfigurable
networking construction. Here, we introduce and verify a chip-based QDS
network, placing the complicated and expensive measurement devices in the
central relay while each user needs only a low-cost transmitter. We demonstrate
the network with a three-node setup using an integrated encoder chip and
decoder chip. By developing a 1-decoy-state one-time universal hash-QDS
protocol, we achieve a maximum signature rate of 0.0414 times per second for a
1 Mbit file over fiber distances up to 200 km, surpassing all current
state-of-the-art QDS experiments. This study validates the feasibility of
chip-based QDS, paving the way for large-scale deployment and integration with
existing fiber infrastructure.
