  We present a scheme for quantum secure direct communication with quantum
encryption. The two authorized users use repeatedly a sequence of the pure
entangled pairs (quantum key) shared for encrypting and decrypting the secret
message carried by the traveling photons directly. For checking eavesdropping,
the two parties perform the single-photon measurements on some decoy particles
before each round. This scheme has the advantage that the pure entangled
quantum signal source is feasible at present and any eavesdropper cannot steal
the message.
