Interesting. keychat (nprofile…swg4) supports free relays and paid relays. You pay 1 sat per note sent to their relay. Very interesting.....
2、 see below note
Good question.
Simplex chat also use signal protocol to achieve end to end encryption.
https://github.com/simplex-chat/simplex-chat/blob/stable/PRIVACY.md
"Simplex chat is the first messenger without user IDs. " This is its most distinctive feature.
“To deliver messages, instead of user IDs used by all other platforms, SimpleX uses temporary anonymous pairwise identifiers of message queues, separate for each of your connections — there are no long term identifiers.”
In my view, Keychat's method of changing the sending and receiving addresses for almost every message is more beneficial for metadata privacy.
I think the number of Simple Chat relays is fewer than the number of Nostr relays. Moreover, the Simplex Chat team has not aimed to integrate with Bitcoin in any way. Could it be said that Simplex Chat does not yet have a viable economic model?
3、yes, two kinds of group.
quotingEncrypted group chats are more challenging to implement than one-on-one chats.
note1927…x9y9
Currently, there is no perfect solution for encrypted group chats, and different designs come with various tradeoffs. Keychat will support multiple types of encrypted group chats to meet different scenarios.
Keychat first implemented the pairwise group, which is designed for small groups of close friends. It offers the highest security, but can only support a limited number of group members.
When sending a message to a group, group member simply deliver a pairwise encrypted message to each member of the group. It simulates group chat using multiple one-on-one private chats. Therefore, it maintains the same forward secrecy and backward secrecy as one-on-one chats.
While certainly simple and secure, it’s not without costs. Instead of delivering one message, a client needs to deliver N messages and pay N ecash stamps.