Abstract:A quantum secure direct communication protocol and a multiparty quantum secret sharing protocol based on Einstein-Podolsky-Rosen pairs and entanglement swapping are presented. The present quantum secure direct communication protocol makes use of the ideal of block transmission. Different from the proposed quantum secure direct communication protocols, the sender can encode one'ssecret message as one of the four Bell states without ensuring the security of the quantum channel firstly. In the multiparty quantum secret sharing protocol, the communication parties adopt checking mode or encoding mode with some probability. It does not need multi-particles entangled state but only Einstein-Podolsky-Rosen pair to realize the protocol. Compared with the proposed quantum secret sharing protocol with entanglement swapping, it is unnecessary for the protocol to perform local unitary operation. The efficiency for the protocol is greatly improved. The securities for both the protocols are the same as that for BBM92 protocol.