Cipher: Offline Wi-Fi Chat

When the other person is on your Wi-Fi, nothing passes through a relay. No phone number. No email. No account. And the things this app cannot protect you from are written down inside it. NO SERVER, BY DEFAULT Cipher tries two transports in order. On the same network it connects over Bonjour, using no infrastructure at all. Only when that is unavailable does it fall back to a relay you chose yourself - and relays are off by default. The transport in use is shown at the top of the screen, and each message carries its own mark: this one arrived over the LAN, this one went through a relay. DRAKE/1 The cryptography is not homemade. X25519, Ed25519, ChaCha20-Poly1305, HKDF-SHA512 and ML-KEM-768 - widely reviewed standards, nothing else. What is ours is how they are assembled. - Keys ratchet forward on every message, so a leaked key cannot open the past - Headers are encrypted too: the message index and key rotations are invisible from outside - Every message is padded up to one of a fixed set of sizes, so the exact length never travels - The routing tag handed to a relay changes hourly, so you cannot be followed across time - Between devices on iOS 26 or later, ML-KEM-768 post-quantum key exchange runs alongside WHAT IT DOES - One-to-one text, with replies, quotes, edits, reactions and search - Disappearing messages, from send or from open, 10 seconds to 4 weeks - Safety-number verification: 60 digits, or scan the QR to compare automatically - Multiple accounts and disposable IDs - Biometric lock, decoy vault, wipe PIN - Encrypted backup and restore, CSV/JSON export - Settings you can actually change, down to the last detail WHAT WE ADMIT A product that sells safety and then overstates it is itself a danger. Settings > What this cannot protect lists the limits in plain language: if the device itself is compromised, if the first key exchange was tampered with, if the person you are talking to copies the contents out, or if you need your IP address hidden - none of those are within reach of this app. PRICING Everything cryptographic is in the free version. Padding, header encryption, key ratcheting, safety-number verification, disappearing messages, blocking - none of it is limited. We do not hold safety hostage. Cipher Pro adds convenience: 14-day relay retention, unlimited disposable IDs, cover traffic. The annual plan includes 7 days free. Terms: https://revot.jp/apps/cipher/terms.html Privacy: https://revot.jp/apps/cipher/privacy.html Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/