Threema OnPrem vs ZIØN

Threema OnPrem is the self-hosted communication solution for organizations with the highest security requirements. The combination of Threema’s proven security architecture and complete data sovereignty creates an independent communication environment that is unmatched in terms of confidentiality – ideal for government agencies, police forces, and industrial companies. Advantages of Threema OnPrem: • 100% data sovereignty through hosting on your own servers • Proven Threema security architecture • Confidential communication in teams, groups, and projects • End-to-end encrypted voice and video calls • Secure exchange of files and documents in all formats • Cross-platform use thanks to mobile app, desktop app, and web client • Additional protection of confidential chats with PIN or fingerprint NOTE: Before you can use this app, Threema OnPrem must be set up on your company server. For more information, visit threema.com/onprem. Enjoy using Threema OnPrem!

ZIØN is a peer-to-peer, end-to-end encrypted messenger built on one principle: your conversations belong to you and your contact — no accounts, no cloud, no message database. HOW YOUR MESSAGES TRAVEL • On the same network, ZIØN connects your devices directly, device to device. Nothing leaves your local network. • Across different networks, messages are carried by a minimal relay we operate that only forwards already-encrypted bytes. It is zero-knowledge by design: it cannot read your messages, your contacts, or any content — and neither can we. • Optional WAN mode (OFF by default): when you enable it, ZIØN can also open a direct device-to-device connection across the internet via UDP hole punching. Only then does the app contact public IP-discovery services (ipify, ifconfig.me, icanhazip, checkip.amazonaws) to learn its own address for NAT traversal. There are no ZIØN accounts and no cloud storage of your messages. The relay never holds anything it can decrypt. STANDARD CRYPTO, ZERO CUSTOM • Curve25519 + ECDH key exchange • Forward Secrecy with per-session ephemeral keys • Authenticated AES-256-GCM message encryption • HMAC-SHA256 handshake authentication (anti-MITM) • 30-digit Signal-style safety numbers OPERATIONAL PRIVACY • Encrypted local storage • Excluded from iCloud backup • Self-destructing messages with configurable timer • Bidirectional message deletion • One-tap Emergency Wipe • Screenshot blocking, screen-recording detection • Session keys wiped from RAM on idle • Anonymous notifications: "New message" only, no sender or content LOCALIZED IN 6 LANGUAGES English, Italiano, Español, Français, Deutsch, 日本語 HONEST DISCLOSURE ZIØN is experimental software and has not undergone formal independent cryptographic audit. For communications where compromise would cause severe harm, use audited solutions like Signal. ZIØN is designed for users who want a second private channel between trusted devices. REQUIREMENTS iPhone 13 or later. iOS 17 or later. Face ID or Touch ID recommended.