Quantum secure communication via a W state

Based on pair-wise entangled W states, we propose three variant protocols for quantum secure communication, i.e., quantum key distribution, partial quantum secret sharing, and their synthesis. By synthesis, we mean that both quantum key distribution and partial quantum secret sharing are executed in a single protocol. For these protocols, we discuss how to detect eavesdropping, including an intercept-resend attack by an eavesdropper.