"The practical applications of quantum encryption may be getting closer. A paper published in Physical Review Letters by Vedran Dunjko, Petros Wallden, and Erika Andersson presents a way to use Quantum Digital Signatures without requiring long term quantum memory.
provides a summary:
Quantum digital signatures (QDSs) allow the sending of messages from one sender to multiple recipients, with the guarantee that messages cannot be forged or tampered with. Additionally, messages cannot be repudiated; if one recipient accepts a message, she is guaranteed that others will accept the same message as well. While messaging with these types of security guarantees are routinely performed in the modern digital world, current technologies only offer security under computational assumptions. QDSs, on the other hand, offer security guaranteed by quantum mechanics. All of the variants of QDSs proposed thus far require long-term, high quality quantum memory, making them unfeasible in the foreseeable future. Here, we present a QDS scheme where no quantum memory is required, which also needs just linear optics. This makes QDSs feasible with current technology."
[Ed. Note] The Physical Review Letters link has all the fun details, but Phys.org provides a more understandable article for the layperson.
Also the arxiv entry for the PRL paper seen here (not a rickroll, promise)
links to this supplementary at
"Part of the security analysis is similar to the one in our earlier paper arXiv:1309.1375, since it uses similar methods applied to a different setting. It is included here in detail, in the supplementary material, for completeness"
I have not studied either in detail but they look interesting.