Reading about the #Session E2E encrypted IM product. White paper at https://getsession.org/
I see that it uses the onion-routed Loki Service Node network, which is tied to some sort of #cryptocurrency #blockchain. Yes, I really do need to read more about blockchains. So far, they do not go deeply into that (thankfully).
They use the cryptocurrency to raise the cost of operating a node, so that it will not be as easy to acquire a significant fraction of the nodes and perform traffic analysis to de-anonymize users. However, I will have to read up on this Loki.