Relaymail: PGP Encrypted Email

relaymail keeps your OpenPGP private key where it belongs: on your YubiKey. Tap to decrypt encrypted mail or sign outgoing messages — your secret key never touches the phone. WHY HARDWARE-BACKED? Most "PGP for mobile" apps either don't decrypt at all, or copy your private key onto the device. relaymail does neither. Every private-key operation runs on the YubiKey itself: the app hands the ECDH (cv25519) or RSA decryption to the card, which does the math and returns the session key. Signing — Ed25519 or RSA — is also performed on-card. Without the YubiKey in your hand, encrypted mail stays sealed and signed mail can't be forged in your name. KEY FEATURES Decrypt and sign on the YubiKey: ECDH cv25519 + RSA for decryption, Ed25519 + RSA for signing Send encrypted and signed mail using your recipients' public keys View and preview attachments — PDF, images, plain text, Office formats and more, with the iOS share sheet for save-to-Files and open-in-other-app Paperclip indicator in the inbox so you can spot mail with attachments at a glance Multiple accounts in one app, plus a unified inbox across them Auto-configuration for iCloud, Gmail, Microsoft, Yahoo and Fastmail Microsoft 365 and Outlook.com accounts sign in with OAuth2 — no app password needed Web Key Directory (WKD) lookup to find recipients' public keys automatically Auto-import of public-key attachments from incoming mail Reply, Reply All and Forward with proper threading headers (In-Reply-To / References) and quoted-original formatting Swipe to mark read/unread, flag, archive, move to junk, or delete — like the system Mail app iCloud sync of accounts and imported public keys across your devices, end-to-end through your private CloudKit container Background fetch with new-mail notifications and an unread badge on the icon Address autocomplete from your iPhone contacts Available in English and Spanish WHAT YOU NEED iPhone with NFC (iPhone 7 or newer), or iPad with USB-C A YubiKey 5 NFC for iPhone, or a YubiKey 5C / 5C NFC for iPad, with the OpenPGP applet provisioned Email account credentials — iCloud, Gmail, Yahoo and Fastmail use app-specific passwords; Microsoft accounts sign in via OAuth2 PRIVACY Your private key never leaves the YubiKey. Period. Public keys are stored locally on your device and (optionally) mirrored to your private CloudKit container so a second device sees the same keyring. Account passwords are stored in iOS Keychain (synced via iCloud Keychain if you have it on). Your contacts are read locally for autocomplete and never sent anywhere. No analytics. No tracking. No third-party servers. Built for OpenPGP users who don't want their private key on the phone.