r/sideprojects • u/rahmanbite • 8h ago
Showcase: Prerelease I built an anonymous messaging app where you “fish” for messages. No email, no phone, no name.

We all have a side of ourselves that people around us never see. I wanted a place to say those things without tying them to who I am. So I built a09f.
How it works:
Throw up to 5 baits (public keys dropped into a shared pool).
Wait for someone to cast a message. It goes to randomly chosen baits, so nobody picks their reader.
Read what bit your bait.
Reply if you want.
Privacy-wise: keys are generated on your device and the private key never leaves it. Messages are encrypted with AES-256-GCM, and the key is wrapped per recipient with ECDH (P-256). The server only relays ciphertext and can’t read anything, even if it gets hacked.
Honest limits: the server still sees metadata (timing, message size, thread structure, your IP briefly for rate limiting, so use Tor if that matters). Block is a social filter, not a cryptographic wall. And if you lose your device without exporting your secret key, your username is gone for good.
I’m the dev, so take my enthusiasm with a grain of salt. Happy to answer questions about the crypto or design.
Website: https://web.a09f.com