Zero-knowledge encryption
Your files are encrypted with AES-256 before they leave your device. We do not hold your keys.
Security
Security is not a feature. It is the foundation.
How ShieldSync protects your files from breaches, from unauthorised access, and from us.
What protects you
Six promises, kept in code.
Authenticated connections
Every transfer, between your devices or to the cloud, runs over an encrypted connection whose other end has proved who it is.
EU-based infrastructure
Cloud storage will run in the EU. Until it launches, syncing is peer-to-peer between your own devices and touches no server of ours.
GDPR at heart
ShieldSync is built in Denmark and follows European privacy law. Your data is never sold.
No tracking, no ads
No analytics, no advertising, no telemetry in the desktop app. We have no reason to scan your data and no way to read it.
Open to scrutiny
We have not yet commissioned an external penetration test. When we do, we will publish the result, including what it found.
Under the hood
What happens to a file before it leaves.
Your password never leaves your browser or your computer. From it, your device makes a key that is slow to guess, and that key unlocks the keys for your files. Each file is cut into pieces and every piece is encrypted on its own before it is uploaded; even the file’s name is hidden.
When you share a folder, its key is wrapped for the other person’s own key, so only they can open it. If someone’s key ever changes unexpectedly, ShieldSync stops and asks you to check it with them first.
AES-256-GCMArgon2idX25519Key pinning
Locked on your device
What we can see
Less than you would expect.
Our servers store locked pieces and the size of each one, because that is how we count your storage. We also see when something changed, so your other devices know to fetch it.
- We can see: how much space you use, and when
- We cannot see: file names, contents or previews
- We cannot reset your encryption: keep your recovery code safe
Noise with a size
How files travel
Direct when it can be, relayed when it can't.
ShieldSync always tries the shortest road first: straight between your computers. When they cannot reach each other, an encrypted relay or your cloud carries the pieces instead.
Straight between your computers
On the same network, computers find each other and connect directly. Across the internet, ShieldSync tries to connect them directly too, even behind most home routers.
- No server in the middle on the same network
- No port forwarding on most routers
Through a blind relay
Some networks will not allow a direct connection. Then the pieces pass through an encrypted relay, which only ever sees encrypted traffic.
- Every connection encrypted and authenticated
Or waiting in your cloud
When the other computer is off, the pieces wait in your cloud, locked, and it catches up as soon as it is back.
- Your cloud only ever stores locked pieces
Data sovereignty
European data. European jurisdiction.
ShieldSync is built in Denmark under EU law. And the strongest protection is not legal at all: we hold no key to your files.
Outside the US CLOUD Act
ShieldSync is built in Denmark, and cloud storage will run in the EU. And since we hold no key to your files, there is no readable copy for any order to reach.
No transfers out of the EEA
We do not plan to transfer your personal data outside the European Economic Area. Any provider we use is named on our sub-processors page first.
True zero knowledge
Even under a lawful Danish court order, ShieldSync cannot decrypt your files. We simply do not have the keys.
| Where | Status | |
|---|---|---|
| ShieldSync and its founder | Denmark, regulated by Datatilsynet | Today |
| Cloud storage | European Union; the provider is named on the sub-processors page before launch | Planned |
| Syncing between your own computers | On your computers only | Today |
Compliance
No badge we haven’t earned.
What we hold, what we don’t, and what we’re working toward.
ShieldSync is new. Certification programmes assume a company with years of audit history behind it, which a new service cannot have yet. We would rather say so than display a badge that would not survive a phone call to the certifying body.
GDPR
In effectWe are a Danish project and the GDPR applies to us today. Our privacy notice sets out every category of data we hold, its legal basis and how long we keep it, and you can export or delete everything from your dashboard without asking us.
Data Processing Agreement
AvailableA DPA covering Article 28 is published and incorporated into our terms for business customers. Our sub-processor list is public and we commit to 30 days’ notice before appointing a new one.
ISO/IEC 27001
Not certifiedWe are not certified and do not claim to be. The architecture is built along ISO 27001 lines — documented access control, encryption at rest and in transit, retention limits enforced in code — but certification requires an accredited audit we have not undertaken. We will publish the certificate here if and when we hold one.
SOC 2
Not auditedNo SOC 2 examination has been performed. When we are large enough for one to be meaningful we will commission it and publish the report under NDA, as is normal. Until then there is nothing to show you.
HIPAA
Not offeredWe do not offer Business Associate Agreements and ShieldSync should not be used for protected health information in the United States. Our encryption model would support it technically; the contractual and operational programme behind it does not exist yet.
Your data
Easy in. Easier out.
Take your files, your settings and everything we know about you with you at any time, for free. Article 20 of the GDPR gives you that right; we build the software around it.
Your files are already local
ShieldSync keeps your files in ordinary folders on your computer. Uninstall the app and they stay exactly where they are. No huge zip downloads.
One-click account export
In your dashboard, Settings then Your data exports a readable file with your settings, devices, sessions, invitations, guest links, file index and activity log. File contents are not in it, because we cannot read them; they are already on your disk.
No exit fees
Some providers charge you to download your own data when you leave. We never do. Leaving is free.
Assessing us
for your organisation?
We would rather answer your security questionnaire honestly than hand you a badge. Ask us anything about the architecture, the data we hold or where it goes.