What a coincidence! I only just discovered that yet another feature is being implemented in Syncthing that would be a perfect fit for a feature I was considering for the messaging platform: encryption for untrusted devices. One of the major disadvantages of a truly p2p, serverless platform is the risk of data loss if all your devices are lost. This risk could be mitigated by a user-friendly backup system among willing participants. Such a backup system would naturally treat the backup hosts as untrusted (even though the human beings involved would typically trust each other) and encrypt the contents prior to syncing the critical user identity and device key pair data for storage on the backup devices.