My naive security architect view is, I get the impression the people doing quantum engineering and those working as cryptographers have a very narrow overlap.
Reading about quantum key agreement/distribution (QKD), it's different from cryptographic functions where you have things like convolution and substitution functions, or using hashing to to distribute the information over a very large finite field. The security in quantum appears inseparable from the encoding and implementation itself, which implies there is a proof and description of entropy-in vs. entropy-out that I haven't gone deep enough to locate and read yet.
I'd speculate there would be some interesting unification of the Shannon information entropy of a plaintext with physical state thermodynamic entropy of the "enciphered" Qbits, given transmitting quantum keys like this sounds more like encoding bits into a physical quantum function than a keyed "encryption" scheme for data for the purposes of security.
To do the data exchange, it's not encrypted to a key per se, but it sounds more like a lookup table (LUT) over a field of qbit state probabilities. Doing certification of the security of such a system is different from a normal NIST algorithm candidate because it reads like you could write and evaluate the encoding scheme as a proof.