  We present a security analysis against collective attacks for the recently
proposed time-energy entanglement-based quantum key distribution protocol,
given the practical constraints of single photon detector efficiency, channel
loss, and finite-key considerations. We find a positive secure-key capacity
when the key length increases beyond $10^4$ for eight-dimensional systems. The
minimum key length required is reduced by the ability to post-select on
coincident single-photon detection events. Including finite-key effects, we
show the ability to establish a shared secret key over a 200 km fiber link.
