Modern delay-tolerant email

Email is inherently a delay-tolerant application. However, modern email deployments involve online checks used by anti-spam mechanisms, non-standard UA/MS interactions, MFA client authentication and hop-by-hop encryption all of which can be problematic in the face of high delays or disruptions, and perhaps especially at scale. The scenario here is where we want to do email in the face of significant delay and disruption, as might be seen in a cislunar network. Previously, students have developed an emulation of a mail deployment for such a network and evaluated some of the effects of delay and disuption on that mail setup. This time around, the focus is likely to be on developing spam mitigation solutions and/or on cryptographic key management, but work on other aspects of realistic email deployments for such scenarios would also be of interest.