Ask HN: Modern distributed sneakernet solution?

Groups working on sensitive software, valuable IP, or other high value targets could mitigate some of the risks of theft or compromise by taking development offline, as could developers and activists in nations that prohibit their activities. Is there a good off-the-shelf tool for people to use for this? There were some active projects around the time of the Snowden leaks but the ones I knew about seem to be dead. My imagined solution would include some kind of indexing/search feature so users know what is available on the broader "network" (really just a list of files, timestamps, and hashes offered by other participants), as well as the ability to "request" files from users who may be more than a single hop away. Participants stay connected by periodically exchanging this index and request data with other members of the network, along with any files they have that have been requested.