  A beam emitted by a displaced thermal source, incident on a beam splitter, is
used as the source in a central broadcast quantum key distribution protocol.
These displaced thermal states have parallels to signals produced through
phase-shift keying, already commonly used in a variety of microwave-based
communications equipment. Here, we analyse a thermal state quantum key
distribution protocol for which there is no dependency on displacement. Our
analysis suggests the ability to carry out QKD using widely available
broadcasting equipment. We also consider the effects of the introduction of
loss at several points in the protocol, and find that, while increasing loss in
Alice's channel eventually results in advantage distillation being required,
security is still maintained.
