blue_ghost
Bluetooth‑Only Encrypted Messenger
// offline · encrypted · serverless
blue_ghost is a free, ad-free Bluetooth-only encrypted messaging app built for hostile, offline, and infrastructure‑denied environments. It uses no servers, no internet, and no cloud. All communication is direct, device‑to‑device over Bluetooth Low Energy — and leaves no trace.
What blue_ghost doesn't do — and why
No Wi‑Fi or Internet — Any network stack beyond Bluetooth dramatically increases exposure to remote attacks, metadata leaks, and traffic correlation. Staying offline keeps your device unreachable and your conversations unobservable.
No Autocorrect or Predictive Text — Modern keyboards send text to external services, maintain local corpora, and log input patterns. Disabling autocorrect prevents keystroke harvesting, model‑training leakage, and injection‑based exploits.
No File or Image Transfer — Files are one of the most common malware vectors. Even images can carry payloads (EXIF data, steganography, malformed decoders). Removing file transfer eliminates an entire class of exploits.
No Voice Messages — Audio requires microphone access, background processing, and codec parsing — all of which expand the attack surface and introduce fingerprinting risks. blue_ghost avoids this by design.
256
AES-GCM bit key
0
Servers contacted
0
Internet permissions
P-256
Hardware-backed keys
App Gallery
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Core Principles
Bluetooth Only
No Wi‑Fi, no cellular. Short-range, infrastructure-free communication that cannot reach the internet.
End-to-End Encrypted
Ephemeral ECDH handshake + Double Ratchet + AES‑256‑GCM. Fresh key on every message.
Minimal Persistence
Session keys, ratchet state, and message history never survive a session end.
Hardware Keys
Identity keys generated and locked inside Android's Trusted Execution Environment. Never extracted.
No Accounts
No phone numbers, no usernames, no email addresses. No registration of any kind.
Seal Ceremony
Secure teardown destroys all session keys, chain state, and message history on exit.
Who It's For
Anyone who needs secure, offline, device‑to‑device communication — from journalists, activists, and security researchers, to field teams operating in infrastructure-denied environments, to people who simply want conversations that don't live forever.
See the full audience breakdown in the FAQ.