OpenKeychain: Easy PGP

OpenKeychain uses OpenPGP encryption to keep your messages private. It manages keys, encrypts/decrypts messages, and works with apps like K-9 Mail. Open-source, free, and security-audited, it supports key exchange, QR scanning, and cross-device use. Learn more at openpgp.org/software. Source code: github.com/open-keychain/open-keychain.