Another option would be something similar to Go's sum database, but with something like a DHT instead of a hosted centralized service. Or perhaps instead of a

Another option would be something similar to Go's sum database, but with something like a DHT instead of a hosted centralized service. Or perhaps instead of a DHT, users could export all their certs to a file and combine/compare entries in a grassroots manner with each other and with devices on different networks.