Five honest picks for holding your family’s digital life privately — by what you actually want. Each winner earns a real category, one pick is ours and clearly labeled as ours, and where the proven players beat us, we say so.
Mature, audited, open-source-client end-to-end encryption for files, passwords, and mail. If "we can’t read it" needs a long track record behind it, this is the pick.
Compare Cornerstone vs Proton →Effortless photos, backup, and Family Sharing — and Advanced Data Protection now brings end-to-end encryption to most of it. Unbeatable if you’re all-in on Apple.
Compare Cornerstone vs Apple iCloud+ →The cheapest big storage and the best photo search. The trade-off is real: it isn’t end-to-end encrypted, and the business model runs on your data.
Compare Cornerstone vs Google One →A box you own outright — maximum sovereignty today, if you’ll happily be your family’s sysadmin for setup, security, and backups.
Compare Cornerstone vs Synology (home NAS) →One private home for the family’s whole digital life — a family AI you can ask, an encrypted vault, kid oversight — where the server holds only ciphertext and refuses your key. New, and honest about it: for proven-today encryption, Proton and Apple are ahead.
See Cornerstone →| Feature | Cornerstone us | Proton | Apple iCloud+ | Google One | Synology (home NAS) |
|---|---|---|---|---|---|
| End-to-end / zero-knowledge encryption | ✓ | ✓ | •ADP opt-in | ✗ | •self-configured |
| Independently audited / proven today | •no (new) | ✓ | ✓ | ✓ | ✓ |
| Encrypted vault for photos + documents | ✓ | ✓ | •ADP | ✗ | •self-configured |
| "What the server sees" proof panel | ★only here | ✗ | ✗ | ✗ | — |
| Private family AI you can ask | ★only here | ✗ | ✗ | •cloud AI | ✗ |
| Age-graded kid access + parent oversight | ★only here | ✗ | •Screen Time | •Family Link | ✗ |
| Cross-platform (not locked to one vendor) | ✓ | ✓ | •Apple-first | ✓ | ✓ |
| Device mesh across the home | •building | ✗ | ✓ | ✓ | ✓ |
| Encrypted cold / off-site backup | •building | ✗ | ✓ | ✓ | •self-configured |
| Self-host / run it on your own box | •roadmap | ✗ | ✗ | ✗ | ✓ |
| No subscription required | ✓ | ✗ | ✗ | ✗ | ✓ |
| Your data is not the business model | ✓ | ✓ | ✓ | ✗ | ✓ |
Prices verified August 2026. Full breakdowns on /compare/cornerstone.