What we promise — and what we don't.
This page is the contract behind the product. Every claim states its limit next to it, because a security promise without its boundary is marketing, not security.
Encryption
Your data is encrypted on your device before it leaves it (AES-256). We cannot read your files' contents.
Where backups live
Backups are stored in ISO 27001-certified Hetzner data centers. That certification covers the infrastructure layer — it is Hetzner's, not ours, and we don't claim otherwise.
Two-layer immutability
Two independent layers protect your backup history. The gate your devices talk to accepts new backups but refuses deletion — a compromised machine can add, never destroy. Beneath it, every storage object carries a compliance lock: until your retention window ends, no one — including us — can delete it.
Key escrow, stated plainly
To make recovery work even when you lose every device, we hold a copy of your encryption key in an isolated escrow. We are therefore not a zero-knowledge provider, and we say so plainly. Key access is restricted, logged, and used only for recovery you initiate and for erasure you request.
Every access to your keys is recorded with its reason and shown to you in your dashboard's key-access log.
Honest limits
Immutability protects history from deletion; it does not prevent a compromised PC from reading its own files. And locked storage means erasure of old snapshots completes when the retention window expires — not before.
Storage redundancy — the facts and the limit, together
Backups are held on erasure-coded storage distributed across multiple servers, able to withstand up to three simultaneous server failures, with redundant power and network. That is Hetzner's infrastructure layer.
That storage is in a single data centre in your chosen location. Hetzner does not replicate between locations and publishes no durability figure. If your compliance regime requires copies in two locations, you can enable a second location — it stores, and bills, twice.
A storage incident can make backups temporarily unreachable even when nothing is lost — this happened at a Hetzner location in August 2026: roughly 21 hours degraded, no data lost. When it happens, you'll see it on ourstatus page.
Erasure
Encryption keys are generated by us, never chosen by you — which is what makes crypto-shredding real. On request we destroy every copy of your key and issue a signed destruction attestation; the remaining ciphertext is permanently unreadable and ages out of storage as its locks expire.
How you leave
On request we hand over a temporary read-only access credential plus your escrowed repository password. Your data is a standard restic repository, readable with open-source tools — no proprietary format, no exit fee. We also export your account metadata: users, devices, job history, audit log. This is also our answer to a GDPR Article 15 access request.
Sub-processors
| Processor | Purpose | Jurisdiction |
|---|---|---|
| Hetzner Online GmbH | Infrastructure and storage | DE / FI |
| Stripe | Payments | USA (SCCs) |
| Resend | Transactional email | sends from eu-west-1 (Ireland); account data, metadata and logs reside in the USA under SCCs and the EU-US Data Privacy Framework |
Restore verification
We periodically restore real samples from your backups and verify them; the dashboard shows when yours last passed. The verification badge means exactly that — a dated, repeated test, not a design assumption.
Reporting a vulnerability
Write to security@proofbackup.com. We respond to good-faith reports and credit researchers who want it.
