Keychat and Damus are both applications based on the Nostr protocol. What are the design differences between Keychat, as an application for posting private notes, and Damus, as an application for posting public notes?

In our view, the Nostr protocol has three main innovative points. First, it boldly allows users to use public keys directly as IDs. Second, it has chosen a relay model where relays do not communicate with each other. Third, it is equivalent to having built-in RSS. 

For Keychat, it utilizes Nostr’s public keys as identities and the relay model but does not use the built-in RSS. Keychat’s contact list is only saved locally for better privacy. 

Keychat has implemented three unique designs. 

To address the issue of message encryption security, Keychat employs the Signal protocol to achieve end-to-end encryption. 

To tackle metadata privacy issues, Keychat separates the sending and receiving addresses from the ID and continuously updates these addresses.

 To ensure that relays can operate sustainably, Keychat uses Bitcoin ecash as postage stamp for messages.