  Quantum cryptographic conferencing (QCC) holds promise for distributing
information-theoretic secure keys among multiple users over long distance.
Limited by the fragility of Greenberger-Horne-Zeilinger (GHZ) state, QCC
networks based on directly distributing GHZ states at long distance still face
big challenge. Another two potential approaches are measurement device
independent QCC and conference key agreement with single-photon interference,
which was proposed based on the post-selection of GHZ states and the
post-selection of W state, respectively. However, implementations of the former
protocol are still heavily constrained by the transmission rate $\eta$ of
optical channels and the complexity of the setups for post-selecting GHZ
states. Meanwhile, the latter protocol cannot be cast to a measurement device
independent prepare-and-measure scheme. Combining the idea of post-selecting
GHZ state and recently proposed twin-field quantum key distribution protocols,
we report a QCC protocol based on weak coherent state interferences named
phase-matching quantum cryptographic conferencing, which is immune to all
detector side-channel attacks. The proposed protocol can improve the key
generation rate from $\mathrm{O}(\eta^N)$ to $\mathrm{O}(\eta^{N-1})$ compared
with the measurement device independent QCC protocols. Meanwhile, it can be
easily scaled up to multiple parties due to its simple setup.
