Frequently Asked Questions

What is CipherMind?

CipherMind is a privacy-first encrypted messaging app for Android and Linux. It uses Signal Protocol for end-to-end encryption, meaning your messages, calls, and media are encrypted on your device before they leave — no one, not even us, can read them.

How is CipherMind different from WhatsApp, Telegram, or Signal?

WhatsApp shares metadata with Meta and stores unencrypted backups by default. Telegram doesn't encrypt chats by default — only "Secret Chats" are E2E encrypted, and groups are never encrypted. Signal is excellent for encryption but lacks advanced protection features. CipherMind combines Signal Protocol encryption with 6 additional security layers: Ghost Mode, Screen Shield, Phantom Metadata, Trust Verify, Vault Lock with Decoy Mode, and Panic Wipe — features no other app offers together.

CipherMind = Signal-level encryption + 6 extra protection layers

Is CipherMind free?

Yes. CipherMind is completely free with no ads, no tracking, and no premium tiers. We don't monetize your data because we don't have your data.

Is CipherMind open source?

The encryption protocol (Signal Protocol) is open source and publicly audited. CipherMind's application code is not currently open source, but our security architecture is fully documented on our Security page.

What encryption does CipherMind use?

Signal Protocol — the same standard used by Signal, WhatsApp, and Google Messages. It includes X3DH key agreement for session establishment and Double Ratchet for ongoing message encryption. Every single message gets a unique encryption key. Even if one key is compromised, past and future messages remain secure (forward secrecy).

Can CipherMind read my messages?

No. Messages are encrypted on your device before being sent. The server only sees encrypted blobs with routing metadata (who to deliver to). We literally cannot read your messages — this isn't a policy, it's a mathematical guarantee.

Not a policy — a mathematical guarantee

What does "Zero Knowledge" mean?

It means our server knows the absolute minimum needed to deliver messages. It sees encrypted data, not content. It sees hashed IPs, not real ones. It sees UUID filenames, not original names. It doesn't know your contact list, your message content, your vault status, or your call content. Check our Security page for the full comparison table.

Are voice calls encrypted?

Yes. Voice calls use WebRTC peer-to-peer connections. The signaling data (SDP/ICE) is encrypted with Signal Protocol before being relayed through our server. The actual audio goes directly between devices — our server never hears your calls.

How do I verify someone's identity?

CipherMind includes Trust Verify — tap a contact's name in chat to see their 60-digit safety number or scan a QR code in person. If their encryption keys ever change (e.g., they reinstalled the app), you'll see an in-chat alert so you can re-verify.

What is CipherMind Shield?

It's our 6-layer protection system that goes beyond encryption: Ghost Mode (self-destructing messages), Screen Shield (screenshot prevention), Phantom Metadata (strips file metadata), Trust Verify (identity verification), Vault Lock with Decoy Mode (hidden conversations), and Panic Wipe (emergency data destruction).

What is Ghost Mode?

Self-destructing messages with timers from 30 seconds to 7 days. The timer starts when the recipient reads the message — not when you send it. Each message disappears independently. In groups, each member's timer starts independently when they read it.

What is Vault Lock and Decoy Mode?

Vault Lock hides sensitive conversations behind a separate PIN. Decoy Mode is the killer feature: set a second PIN that, when entered, shows an empty vault — giving you plausible deniability. Even under pressure, entering the decoy PIN reveals nothing. The real PIN shows your hidden conversations. The server has zero knowledge of vault state.

Plausible deniability — enter the decoy PIN and the vault appears empty

What is Panic Wipe?

Emergency data destruction. Long-press the lock icon for 3 seconds, enter your PIN, confirm with biometrics — all local data is wiped instantly: database, encryption keys, preferences, cached media, everything. No server communication is needed. The server token expires naturally. This is irreversible — designed for real emergencies.

Does Screen Shield actually prevent screenshots?

On Android, yes — it uses FLAG_SECURE, the same system-level protection used by banking apps. The screen appears black in screenshots and screen recordings. On Linux desktop, a toggle is available but OS-level enforcement varies.

What metadata does Phantom Metadata strip?

Photos: all EXIF data (GPS location, camera model, timestamps, lens info) is stripped by re-encoding. Audio: WAV files are reconstructed to keep only audio data — encoder info, recording software names, and embedded text are removed. Filenames are replaced with random hex strings. The server stores files with UUID names and application/octet-stream content type.

What data does CipherMind store on the server?

The bare minimum for message delivery: your email (hashed), display name, encryption keys, and encrypted message blobs in transit. Messages are auto-deleted: 72 hours after delivery, 17 days if undelivered. IP addresses are hashed before logging. We don't store your contact list, message content, call audio, or location.

Can anyone see my online status?

Only if you allow it. Privacy settings let you control who sees your online status, last seen time, and read receipts. These are enforced server-side — not just hidden client-side. When you disable online status, the server actively stops broadcasting your presence to other users.

Server-enforced — not just hidden on your screen

What happens when I block someone?

Silent blocking. The blocked person sees no indication they've been blocked — their messages appear to send normally (with a checkmark) but are silently dropped by the server. They can't see your online status, can't call you, and presence updates stop in both directions. 5 server-side layers ensure complete invisibility.

Are backups encrypted?

Yes. CipherMind backups use AES-256-GCM encryption with a password-derived key (PBKDF2, 100,000 iterations). The .cmbackup file contains your database, encryption keys, and preferences — all encrypted. Without your password, the file is cryptographically unreadable.

What platforms does CipherMind support?

Android (7.0+, ARM64) and Linux (x86_64) are available now. Windows, iOS, and macOS are planned for V2.

Why isn't CipherMind on the Play Store or App Store?

We're preparing for store submission. In the meantime, you can download the APK directly from our Download page. The APK is the same release build — compiled with code obfuscation for security.

How do I install the APK on Android?

Download the APK from our Download page, then open it. Android will prompt you to enable "Install from unknown sources" for your browser — this is a one-time setting. Tap Install and you're done.

Can I use CipherMind on multiple devices?

CipherMind enforces single-device security. When you log in on a new device, all other sessions are immediately terminated — encryption keys are cleared, WebSocket connections are closed, and the old device is notified. This prevents session hijacking and ensures your encryption keys exist on only one device at a time.

One device, one session — no key duplication

Does CipherMind support group chats?

Yes. Group chats with encrypted messaging, group voice calls (coming soon), admin controls, and member management. Ghost Mode works in groups too — each member's timer starts independently when they read the message.

Can I search my messages?

Yes. Message search runs entirely on your device against your local encrypted database. No search queries are ever sent to the server. Results include navigation with count and highlight.

Does CipherMind support View Once media?

Yes. Send photos that can only be viewed once. Screen Shield activates automatically during viewing. After closing, the media is permanently deleted from the recipient's device. No reply or forwarding allowed on view-once media.

Can I customize the appearance?

Yes. CipherMind includes 8 chat theme presets (CipherMind, Ocean Blue, Aurora, Sunset, Rose, Mint, Storm, Ember) plus custom notification tones. Dark mode is the default with full light mode support.

What about two-factor authentication?

CipherMind supports TOTP-based 2FA via any authenticator app (Google Authenticator, Authy, etc.). When enabled, login requires both your password and a 6-digit code. 8 single-use recovery codes are provided as backup. TOTP secrets are encrypted at rest on the server with AES-256-GCM.

I lost my PIN / recovery codes. Can you help?

No. CipherMind uses zero-knowledge architecture — we don't have your PIN, encryption keys, or recovery codes. This is by design. If you lose all recovery methods, your only option is to create a new account. This is the trade-off of true zero-knowledge security.

I activated Panic Wipe accidentally. Can data be recovered?

No. Panic Wipe permanently destroys all local data — database, encryption keys, preferences, and cached media. This is irreversible by design. If you had a backup (.cmbackup file), you can restore from that after creating a new session.

Messages show "[Encrypted message]" in my notification.

This is normal. Push notifications are sent as data-only messages — the notification content is generated locally on your device after decryption. If you see [Encrypted message], it means the notification arrived before decryption completed. Opening the app will show the actual message.