SecureBit.chat is a browser-based, peer-to-peer messenger built on **WebRTC** and the **Web Crypto API**. Two people establish a direct, end-to-end encrypted channel and verify each other in person — there is no registration, no central server relaying or storing messages, and no metadata account to leak. Everything cryptographic happens locally in the two browsers.
It is designed for people who need a small, auditable, zero-infrastructure way to talk privately: journalists and sources, security researchers, or anyone who simply wants a conversation that leaves nothing behind.
- ECDH P-384 key agreement with derived per-session keys, AES-256-GCM payloads, and DTLS-protected transport.
- Interactive **Short Authentication String (SAS)** verification — you confirm a code out-of-band before the session is trusted, defeating man-in-the-middle attacks.
- Replay protection, message integrity (HMAC), and a live security report you can open at any time during a call.
- **Encrypted voice messages** — record in the browser and send over the same end-to-end encrypted transfer channel as files. Audio is captured as PCM/WAV, integrity-protected by a signed hash, and played back inline on the recipient's device without ever touching disk.
- Run several independent chats at the same time. Every conversation gets its own encrypted session, keys and verification, so two chats can never mix.
- A side panel lists your open chats with unread badges. Switching is instant, and starting a new chat leaves the others connected.
- Set your availability (Available, Away, Busy or Invisible) and connected peers can see it. You can also give each chat a private label that is stored only on your device and is never sent to the other side.
A session is **not** treated as verified until both peers complete the SAS flow. This is the step that protects you against a man-in-the-middle: the code must be compared through a channel an attacker cannot impersonate.
> SecureBit.chat is privacy software, not a guarantee. View-once and disappearing messages are cooperative (not screenshot-proof), and a TURN relay can observe both peers' IPs and traffic timing — though never message contents. See [`SECURITY_DISCLAIMER.md`](SECURITY_DISCLAIMER.md).
SecureBit is a PWA — open it in a supported browser and choose **Install** (or *Add to Home Screen* on mobile) to run it as a standalone, offline-capable app.
Incoming transfers require explicit consent. Metadata is validated and dangerous names rejected before the prompt appears. Accepted: common raster images, PDF, plain text, and ZIP. Executable/scriptable formats (`.exe`, `.bat`, `.sh`, `.js`, `.msi`, `.dmg`, `.jar`, `.ps1`, `.vbs`, `.html`, `.svg`, …) are blocked, and MIME type must agree with the file extension.
Issues and pull requests are welcome. SecureBit.chat is intended for lawful, ethical communication only — please read [`RESPONSIBLE_USE.md`](RESPONSIBLE_USE.md) before using or contributing.
