B3 is a private encrypted messenger for Android. Messages, calls and files are sealed on your device with post-quantum PQXDH (ML-KEM-1024 + X25519). No phone number, no Google, no ads — so what you say today stays unreadable even to the computers of tomorrow.
A full private-comms toolkit in one app: messaging, calls, file transfer, and an encrypted personal vault.
1-to-1 chats encrypted on your device before they ever touch the network. The server only ever sees opaque ciphertext.
Voice, video and push-to-talk calls with DTLS-SRTP media encryption. Media is relayed on purpose, so neither side ever learns the other’s IP address.
Send documents, photos and media end-to-end encrypted over the same relayed channel — the person you send to never sees your address.
A private space for sensitive files, notes and your calendar, all locked behind the same on-device encryption.
Events, reminders and birthdays with exact on-time alarms and deep-links, stored locally, never synced to the cloud.
Add contacts by scanning a QR code, exchanging identity keys in person so you know exactly who you're talking to.
Only the person who created a group can change who is in it, and every phone checks that signature before accepting a change. Nobody can quietly add a silent reader.
A small companion app keeps messages and calls arriving while your phone sleeps. No Google services involved, and the nudge it receives carries no content at all.
Send voice messages, share updates that disappear after 12 hours, and forward anything onward — each copy encrypted fresh for whoever receives it.
Every layer assumes the network, and even the server, is hostile. Here's what's standing between your data and everyone else.
Messages are encrypted on your device with PQXDH — X25519 combined with ML-KEM-1024 (NIST FIPS-203) — so traffic captured today cannot be unlocked later by a quantum computer. The server relays ciphertext it cannot decrypt.
Your identity keys live in the Android Keystore (StrongBox where available), generated and used inside secure hardware, never exported.
Chat history is stored in a SQLCipher database, keyed by a 256-bit secret sealed under a Keystore master key.
Messages can self-destruct on read, are deleted on delivery, and any undelivered copy is purged from the server within hours.
A duress passcode instantly destroys all local data: identity, sessions, the database and its key, leaving nothing to recover.
The app trusts only B3’s private root certificate authority for its server connection. Public authorities are excluded, so a certificate wrongly issued by any of them is refused.
You authenticate by signing a server challenge with your private key. No passwords to phish, and a stolen ID can't impersonate you.
User, device and prekey records are keyed by HMAC-SHA256 hashes, so the database doesn't hold your raw identity in the clear.
Every message is sealed with its own one-time key, derived from a forward-ratcheting chain. No two messages share encryption, so compromising one message’s key leaves every other message sealed.
Share a moment that burns the instant it's viewed. Screenshots are blocked, it stays strictly between the two of you, and vanishes once seen.
No mystery crypto. Standard, audited primitives, applied client-side, end to end.
B3 starts each conversation with PQXDH — X25519 plus ML-KEM-1024 (NIST FIPS-203) — then a Double Ratchet so every message has its own key. A prekey bundle lets you write to someone who is offline. Call media rides DTLS-SRTP. Public keys are the only key material the server ever stores.
Signal is the audited default if you will give it a phone number. B3 is for people who will not — and who will not run Google on the phone.
| B3 | Signal | Telegram | ||
|---|---|---|---|---|
| Phone number | Not required | Required | Required | Required |
| E2E by default | Yes | Yes | Yes | Cloud chats: no |
| Post-quantum setup | PQXDH · ML-KEM-1024 | PQXDH | — | No |
| Google push | None | Optional | Yes | Yes |
| Ads | None | None | Meta ads graph | Sponsored |
B3 is a private encrypted messenger for Android. Your identity is a cryptographic key generated on the device, not a phone number. Messages, calls and files are end-to-end encrypted with post-quantum PQXDH before they leave the phone. There is also an encrypted vault and a local calendar that never sync to a cloud.
No. You do not give B3 a SIM, an email, or a name to create an account. The account is the key. You add people by scanning a QR code or sharing a B3 ID.
No. There is no key escrow, no silent extra recipient, and no plaintext fallback. If B3 cannot encrypt to a verified key, it does not send. The server only ever sees ciphertext. A compelled operator can be shown routing metadata — not message contents.
The initial key agreement is PQXDH: X25519 plus ML-KEM-1024 (NIST FIPS-203). That protects archived handshakes against a future quantum computer. The Double Ratchet that follows is classical, the same class as Signal’s PQXDH. Details: the security model.
No Google account, no Firebase Cloud Messaging, no advertising SDK, no third-party analytics. A small co-signed companion app wakes the messenger so messages still arrive while the phone sleeps. That wake carries no content.
Yes if you will not hand a messenger your phone number, or you will not run Google services. Signal remains the well-audited reference for this protocol family. B3 uses the same design in its own code, and adds a vault, calendar, IP-hiding call relay, and a Google-free wake. It has not had a third-party cryptographic audit yet.
Get the Android APK from this site (Android 8.0 and newer). Allow the browser to install it, open B3, and create an identity on the device. There is no cloud account to recover: the key is the account.
Take B3's privacy to your whole organization. Self-hosted messaging, a managed VPN and private email, all running on infrastructure you control.
Deploy B3 on your own servers. End-to-end encrypted chat, calls and file transfer for your entire team, with no outside party in the loop.
A WireGuard-based VPN for your organization: secure remote access and encrypted tunnels between offices, sites and devices.
Custom-domain mailboxes on infrastructure you control, with strong encryption and aggressive, minimal data-retention policies.
Dedicated infrastructure, admin controls, onboarding and direct support, tailored to institutions with strict privacy and compliance needs.
Your servers or ours. Run B3 on our hardened, privacy-first servers, or deploy it entirely on a private server your organization owns and trusts.
Install B3 and start communicating on your terms: encrypted, post-quantum, and yours alone.
B3 gives you strong content confidentiality. Like any messenger it needs some routing data to deliver your messages, but we don't keep it. The server auto-wipes everything every few hours: any logs we must hold for delivery get purged clean, metadata included. We believe in being honest about what encryption does and doesn't protect.
B3 isn't publicly available yet. To get access or an invite, reach out and we'll get you set up.
Contact sayhello@bfree.st