What is zero-knowledge encryption?
With zero-knowledge encryption, your files are encrypted before they reach the host, which never holds the key. It therefore cannot read your data, nor hand it over in clear text to a third party, even under a court order. Only your password can decrypt it. The topic continues in chapter 6 of my book, Vivre sans Google.
Information verified on July 13, 2026
Picture a safe deposit box at the bank, with you holding the only key. The banker keeps the box, maintains it, protects it from burglars. But opening it? Impossible for him. Zero-knowledge encryption applies that principle to your files: they are encrypted on your device before upload, and the host never receives the key.
The consequence is radical. A curious employee, a hacker breaking into the servers, or even a court demanding your data: they all leave with the same thing, unreadable ciphertext. That is the whole difference with a classic cloud like Google Drive, where the host can technically read, analyze and hand over your files.
This protection comes with a trade-off you should know before signing up: if you lose your password, nobody can rescue you. No “forgot password” button that restores everything: you were the key. The principle is a close cousin of end-to-end encryption, applied to storage rather than conversations.
Where it plays out: chapter 6 of the book organizes your exit from Google Drive, and the Cloud and storage category compares zero-knowledge services.
This topic is chapter 6 of my book
It answers these questions, among others:
- how do you empty Google Drive without losing anything, Google Docs included?
- encrypted cloud, NAS or personal server: which one fits your profile?
- and what does a NAS at home really involve, day to day?
Forthcoming 22/10/2026 from Éditions Eyrolles
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Tech jargon, translated
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