  In this paper, we describe a robust quantum cryptography scheme with a
heralded single photon source based on the decoy-state method, which has been
shown by numerical simulations to be advantageous compared with many other
practical schemes not only with respect to the secure key generation rate but
also to secure transmission distance. We have experimentally tested this
scheme, and the results support the conclusions from numerical simulations
well. Although there still exist many deficiencies in our present systems, it's
still sufficient to demonstrate the advantages of the scheme. Besides, even
when cost and technological feasibility are taken into account, our scheme is
still quite promising in the implementation of tomorrow's quantum cryptography.
