What Is Zero-Knowledge Encryption?
Zero-knowledge encryption means that the company providing a service has zero knowledge of the data you store with it. Your information is encrypted on your own device with a key that only you hold, so the provider stores — at most — an unreadable blob. Even if their servers were seized or breached, there would be nothing legible to hand over.
In short: with zero-knowledge encryption, you hold the keys, not the company.
Zero-knowledge vs. "encrypted" in finance apps
Most finance apps advertise "bank-level encryption." That usually means your data is encrypted in transit (TLS) and at rest on the company's servers — but the company still holds the decryption keys. They can read your transactions to categorize them, train models, or power features. If their database is breached or subpoenaed, your financial history is exposed.
Zero-knowledge is a stronger promise. The provider never holds a key that can decrypt your data, so there is no copy of your financial life for them to read, sell, or lose.
| Standard "encrypted" app | Zero-knowledge approach | |
|---|---|---|
| Who can read your data | The company (and its vendors) | Only you |
| Where decryption keys live | Company servers | Your device |
| What a server breach exposes | Your full financial history | Nothing readable |
| Data sold to third parties | Possible | Architecturally impossible |
How nint applies it
nint is built so that your financial data stays on your device. Transactions, budgets, and goals live in a local vault protected by AES-256 encryption, and the keys are tied to your device's secure enclave and unlocked with biometrics (Face ID / Touch ID). Multi-device sync uses Apple's end-to-end encrypted iCloud (CloudKit) — data is encrypted before it leaves your device and only decrypted on your other devices. Only you hold the keys; not even nint can read your data.
What nint's servers hold is deliberately tiny: your email, subscription status, and app preferences. Zero financial data ever reaches us — which is why we literally cannot sell it, and why a breach of our servers would expose no transactions at all.
For a full walkthrough of the vault, the sync model, and what we do and don't store, see our privacy architecture.
Why it matters for your money
- Breach resistance — there is no central store of your transactions to steal.
- No data sales — a company that cannot read your data cannot monetize it.
- Real deletion — delete your data and it's gone, with no cloud copies to chase.
- Trust by design, not by policy — your privacy doesn't depend on a promise that could change; it's enforced by the architecture.
Related reading
- Privacy architecture — how nint's local-first vault and encrypted sync fit together.
- Pricing — nint's free tier keeps your data local at no cost; paid tiers add sync and linking without changing the privacy model.
- Blog: Why your financial data should stay on your device
Ready to keep your money private by design? Start with the free tier — no credit card, no bank credentials.