  Practical schemes for measurement-device-independent quantum key distribution
using phase and path or time encoding are presented. In addition to immunity to
existing loopholes in detection systems, our setup employs simple encoding and
decoding modules without relying on polarization maintenance or optical
switches. Moreover, by employing a modified sifting technique to handle the
dead-time limitations in single-photon detectors, our scheme can be run with
only two single-photon detectors. With a phase-postselection technique, a
decoy-state variant of our scheme is also proposed, whose key generation rate
scales linearly with the channel transmittance.
