Thanks!
Here is the foss equivalent of this project: https://github.com/positive-intentions/chat
Unfortunately, open source isn't sustainable. I'm investigating close-source as a way to create something competitive. My plan is to try to sell it on the Play store.
As for pairdrop, their approach to peer discovery relies on knowing the network you're connected to. This makes it easy to find peers in cases where you use the same WiFi network. In mine I'm using WebRTC to allow connections over the internet. Peer discovery is achieved by using crypto-random IDs exchanged as a link or QR code.
Ultimately it's worth noting my app is a work in progress. I hope I can update the UX to make the functionality as seamless as pairdrop.
Nice! Can you tell me more about zero-knowledge encryption?
In my app I'm using asymmetric encryption to exchange a symmetric encryption key (Diffie-helman). I'm curious about other approaches for P2P authentication.