  The control of light scattering is essential in many quantum optical
experiments. Wavefront shaping is a technique used for ultimate control over
wave propagation in multiple-scattering materials by adaptive manipulation of
incident waves. We control the propagation of single-photon Fock states in
opaque scattering materials by phase modulation of the incident wavefront. We
enhance the probability that a single photon arrives in a target output mode
with a factor 10. Our proof-of-principle experiment shows that wavefront
shaping can be applied to non-classical light, with prospective applications in
quantum communication and quantum cryptography.
