03 — Proton
Making zero-knowledge encryption feel as easy as Gmail.
Overview
Built from scratch.
Encryption included.
2020. Proton was expanding from secure email into a full privacy-first suite. Two missions: design Proton Calendar from scratch, and shape the unified system tying Mail, Calendar, and Drive together. Both light and dark, in lockstep.
Designing trust
Encryption that disappears into the experience.
Keys, ciphers, and zero-access were never the user's problem. The onboarding looked like any other app; quick form, clear progress, while keys generated and the mailbox locked itself down. Familiar surface, fortress underneath.
Calendar from zero
A month view that reads like Google's. But yours alone.
Familiar dots, familiar grid, multi-calendar overlay, color logic borrowed from the patterns people already know. Nothing about the surface gives away that every event title, attendee, and note is end-to-end encrypted before it leaves your device.
Recurrence
One event, every Monday and Friday.
I designed the full event creation flow, including the recurrence rule editor; daily, weekly on selected days, monthly, custom. The grid shows the pattern instantly so you know the event will repeat exactly the way you meant.
End-to-end encryption
Even Proton can't read your schedule.
Title, description, location, attendees are all encrypted on-device before sync. Proton Calendar is the only calendar in the world that uses end-to-end encryption and cryptographic verification to protect your entire schedule. My job was to make sure that promise didn't feel scary, technical, or in the way.
Light & dark mode
One system, two skins.
Mail, Calendar, and Drive share the same tokens, the same components, the same encryption guarantees. Rendered in either light or dark depending on what you prefer.
Key Design Decisions
Encryption behind the scenes
Keys, ciphers, and zero-access happen invisibly. The user signs up with a familiar form. Proton handles the cryptography in the background.
Progressive disclosure
No crypto jargon by default. Tap to learn more if you want the technical detail but never forced on people who just need a calendar.
Audited UI patterns
Lock icons, online-banking confirmation flows, familiar transaction patterns, borrowed conventions reduce cognitive load and quietly signal security.
One system, three apps
Tokens, components, and patterns shared across Mail, Calendar, and the coming Drive, so the suite felt like one product, not three.
Outcomes & Learnings
01
Proton Calendar shipped as the world's only end-to-end encrypted calendar with cryptographic verification. Encryption was invisible to the user.
02
The unified design system became the backbone for Proton Mail, Calendar, and the Drive launch. Three apps that felt like one cohesive privacy suite.
03
Key learning: trust is built by what users don't notice. The strongest privacy UX is the one that gets out of the way.
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