Important advances have recently been made in high-performance single-photon sources that bring such possibilities closer to reality. In particular, single photons can be used to implement absolutely secure optical communication, also known as quantum cryptography. With this new source, recording a single-photon signature that took eight hours five years back can now be achieved on a millisecond time scale. This remarkable progress was achieved by developing a novel type of microcavity structure which strongly enhances the light extraction from the optically active material.