One of the often mentioned problems with grin is impossibility of securely producing transaction while two parties are not online simultaneously. It is possible to use messenger applications to exchange slatepacks but that requires to partially reveal ones identity. Inspired by this forum post I had an idea to draft a protocol allowing to outsource the work of online listener in exchange for a fee paid in grin.
I describe the idea in the repository linked below. I would really appreciate if you helped review it and contributed. I will accept pull requests to this file if there are any and welcome all the feedback.