XEP-Remarks/XEP-0373: OpenPGP for XMPP
Key publication, notification and retrieval
The XEP has undergone already one change regarding key publication, notification and retrieval. The initial used approach was found to be quite traffic demanding, because the full key data was pushed to interested entities every time they appeared online. Thus it was decided to split the key into metadata and data PubSub/PEP nodes.
While it turned out to work quite well, it is not elegant with regard to the mechanisms the involved protocols provide. From a pure "what the specification describes" POV an ideal solution would possibly be to
* Use XEP-0060 "notification only" nodes, which would only push the node id to the subscribed entity (but was only recently implemented in prosody and the feature is not discoverable, most likely because it appears to be mandatory by XEP-0060).