Just published this blog post on the state of open-source protocols for E2E encrypted communication in the group setting. We discuss protocols from Signal, XMPP and Matrix. Another very interesting area of cryptography other than zk! 

https://blog.bigwhalelabs.com/an-incomplete-guide-to-e2e-encrypted-groups/

The current UX of encrypted group chats leaves something to be desired. Would love to hear of instances where people wished they had better/more features on their group chats and why! Latest in our series on crypto x social at Big Whale Labs.