Universal Security Requirements for All Proton Apps

End-to-End Encryption (E2EE): All user data is encrypted end-to-end.

Zero-Access Encryption: Proton servers never access unencrypted user data.

HMAC with SHA-384: Ensures data integrity and message authentication.

Combination of AES-256 with RSA-4096: AES-256 for symmetric encryption of data; RSA-4096 for key exchange.

Post-Quantum Cryptography:

CRYSTALS-Kyber for quantum-resistant key encapsulation.

CRYSTALS-Dilithium for digital signatures.

Combination of CRYSTALS-Kyber with SPHINCS+: Maximizes quantum attack resistance and cryptographic diversity.

Combination of CRYSTALS-Dilithium with NTRU: Balances security and performance.

1. Proton Notes

Secure, end-to-end encrypted notes with rich formatting, tagging, search, and cross-device sync.

Local AES-256 encryption, zero-knowledge sync protocol, integrated with Proton Drive.

1. Proton Contacts

Encrypted contact management with import/export (vCard/CSV), group management, and synchronization.

End-to-end encrypted storage, integration with Proton Mail.

1. Proton Phone

Encrypted voice and video calls, secure messaging using Signal Protocol or Matrix MLS.

Privacy-first communication integrated with Proton Contacts.

1. Proton IMAP/SMTP Bridge

Secure IMAP/SMTP access for free users supporting popular email clients (Thunderbird, Outlook).

OAuth2 authentication, TLS 1.3 encryption, PKCE support.

1. Proton Media (Photos & Videos)

Secure storage, viewing, and sharing of photos and videos with encrypted albums and automatic mobile backup.

Integration with Proton Drive; password-protected and expiring share links.

1. Proton Social

Private social networking platform with end-to-end encryption built on decentralized protocols (Matrix/ActivityPub).

Proton ID authentication; ad-free and user data controlled.

1. Proton Browser

Privacy-centric browser with built-in tracker blocking, HTTPS enforcement, DNS-over-HTTPS/TLS, integrated with Proton services.

Fork of Firefox ESR or Chromium enhanced for privacy.

1. Proton Tasks & Reminders

Encrypted task and reminder management with deadlines, priorities, recurring tasks, and integration with Proton Calendar.

Cross-device synchronization.

1. Proton Smart Switch

Encrypted peer-to-peer sharing of files, apps, contacts, and settings between devices.

QR code pairing, Bluetooth/Wi-Fi Direct support.

1. Proton Mobile Security

Antivirus, phishing protection, app monitoring, VPN integration, and network threat defense.

Real-time threat updates and local scanning.

1. Proton OS & Proton Market

Privacy-focused Linux-based operating system for PCs and mobile devices.

Proton Market: a secure app store with privacy-audited apps.

1. Proton Translate

Privacy-first translation service supporting multiple languages with offline and encrypted cloud modes.

Independent from Google Translate.

1. Proton Clock & Alarm

World clock, alarms, timers, and stopwatch with encrypted settings and synchronization.

Privacy-focused time management tools.

1. Proton Maps

Privacy-respecting maps with offline navigation, search, routing, and traffic info using OpenStreetMap data.

Encrypted queries and local caching to prevent tracking.