Cloud storage that locks your files before they leave your device
Zero-knowledge storage encrypts files on your phone or computer. The storage company keeps the scrambled data, and you keep the key. This guide shows how that works and what to check before you subscribe.
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- PDFTax-return-2025.pdf1.2 MB
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- XLSBudget-2026.xlsx88 KB
- JPGSigned-contract-scan.jpg4.6 MB
You hold the key, so your devices can open and read every file. Without your key, the company's servers hold only scrambled data.
Illustration of zero-knowledge encryption, not a screenshot of the product.
The difference is who holds the key
Most cloud storage encrypts files too. What changes with a zero-knowledge service is where that happens and who is able to undo it.
| Typical cloud storage | Zero-knowledge storage | |
|---|---|---|
| Where files are encrypted | Usually on the company's servers, after upload. | On your device, before upload. |
| Who holds the key | The company. | You. |
| What the company can read | File contents, if its systems need to. | Scrambled data only. |
| If you forget your password | The company can reset your access. | You need your backup key. The company cannot unlock the files for you. |
What the service we feature includes
These points come from the provider's own published material. Check its site for the details of each plan.
Zero-knowledge on every file
Encryption is applied by default, with no separate vault to set up.
Post-quantum encryption
Key protection designed to hold up against future quantum computers, alongside AES-256.
Open-source, audited code
The apps' code is public, and an outside security firm has reviewed it.
Apps for your devices
Windows, macOS, Linux, Android, iOS and a web app.
Private sharing
Send files or folders by link and restrict access when you need to.
European privacy rules
The company is based in the EU and operates under GDPR.
Questions worth asking before you subscribe
What does zero-knowledge mean?
The storage company has no knowledge of your key, so it cannot read what you store. Files are encrypted on your device first, and only devices signed in with your credentials can decrypt them.
What is post-quantum encryption?
A newer family of encryption methods built to resist attacks from quantum computers, which are expected to weaken some of today's standard methods. It protects the keys that lock your files.
What happens if I forget my password?
Because the company does not hold your key, it cannot open your files for you. You will need the backup key issued when you set up the account, so store it somewhere safe.
How is it billed?
Plans are paid subscriptions, billed monthly or annually, and they renew until you cancel. The provider lists a 30-day refund window on paid plans. Check the current price, the renewal price and the refund terms at checkout.
Compare the plans on the provider's site
You will leave this page. Storage sizes, prices and terms are shown there before you pay.
Go to the storage plans