How HypaVault Protects Your Files
HypaVault encrypts everything you store with AES-256-GCM on your phone before it's saved, and nothing you store ever reaches us. Here's how, in plain words, with the technical details and the standards behind them below.
Encrypted Before It's Saved
Your passcode is the lock, and only your phone holds the key that goes with it.
A Key for Every File
Each vault has its own random 256-bit key, and every file its own key too. Files are encrypted with AES-256-GCM, along with their names, folders, notes and thumbnails.
Your Passcode Is the Lock
Your 6-digit passcode is stretched with Argon2id and combined with a device key kept in your phone's secure storage (the iOS Keychain, or a key protected by the Android Keystore). That key isn't in iCloud, computer or Google backups, so a copy of the vault's files isn't enough to start guessing.
Guessing Is Slowed Down
After 5 wrong tries the lock screen waits 30 seconds, doubling after each miss, up to an hour. Recovery phrase tries are limited the same way.
Your Recovery Phrase
Twelve words, shown once and never stored. They open your backups and reset a forgotten passcode. Lose both, and nobody, including us, can get the data back.
Nothing to Find
The phone always holds four identical-looking key slots, used or not. Without a passcode there's no list, count or name of vaults anywhere.
Safe Under Pressure
With Pro, a duress passcode looks like a normal unlock, silently erases every other vault's key and opens an empty vault. A backup and its recovery phrase bring an erased vault back.
Covered When You Leave
The vault locks when you leave the app, or 30 seconds later if you choose, and a cover hides it in the app switcher. On Android, screenshots and screen recordings of the app show black. Seed phrase words show only while held, and copied secrets clear after 60 seconds.
Kept Safe, Never Seen by Us
Every file is verified after import, changes save all at once or not at all, and a weekly spot check looks for damage. Backups, shared copies and sync are encrypted on the phone, padded to a standard size, and carry no device, name or identity data. Nothing you store ever reaches us.
For the Technically Curious
The exact algorithms and settings behind everything above.
| What | How |
|---|---|
| Encryption at Rest | AES-256-GCM, a random 12-byte IV per piece and a 16-byte tag. Each file is split into 4 MB pieces, and each file has its own random 256-bit key. |
| What's Encrypted | File contents, thumbnails, every name (files, folders, notes, vaults), notes and seed words, folder structure, settings, the plan and counts. |
| Vault Key | 32 random bytes per vault. Sub-keys are derived with HKDF-SHA-256. |
| Passcode | 6 digits, stretched with Argon2id (19 MiB memory, 2 iterations), then bound to the device key with HMAC-SHA-256. |
| Device Key | iOS: a Keychain item for this device only, not in iCloud or computer backups. Android: a key wrapped by a non-exportable Android Keystore key (StrongBox when the phone has it), not in Google cloud backup. |
| Recovery Phrase | 12 words, BIP39 standard, 128 bits of entropy. Stretched with Argon2id (64 MiB, 3 iterations). Never stored. |
| Key Slots | Four fixed slots on every phone, used or not, indistinguishable from random. An unlock tries all four at once, and a miss gives the same answer whatever the reason. |
| Lockout | 5 wrong tries: 30 seconds. Then doubling with each try, capped at 1 hour. |
| Duress | One write overwrites every other vault's key slot with random bytes. Their files are then deleted in the background. |
| Backups (.hypa) | 1 MiB segments, each AES-256-GCM, protected against truncation and reordering. Padded to standard sizes, with no device or identity data. Opened by the recovery phrase. |
| Shared Copies | Wrapped by a one-time 25-character share code (125 bits) through Argon2id, and re-encrypted with new keys when the recipient imports them. |
| Sync | WebRTC directly between the two phones, with no STUN, TURN or signalling server, so it only works on the local network. Paired by QR codes carrying a one-time 32-byte pairing key, which seals every piece on top of WebRTC's own encryption. |
| Network | The app's interface makes no network calls of its own. The only outside service is RevenueCat, for purchases. |
| Integrity | Verified imports, journaled all-or-nothing writes, and a weekly check of 24 random pieces. |
Standards We Use
The cryptography above comes from published standards, not methods we invented. Each link opens the primary source, so you can check the details yourself.
| Standard | Where HypaVault Uses It |
|---|---|
| NIST FIPS 197Advanced Encryption Standard (AES) | AES with a 256-bit key, the cipher that encrypts every file, name, note and thumbnail in your vault. |
| NIST SP 800-38DGalois/Counter Mode (GCM) and GMAC | GCM, the authenticated encryption mode applied to every piece, with a random 12-byte IV and a 16-byte tag. |
| RFC 9106Argon2 Memory-Hard Function | Argon2id stretches your passcode (19 MiB, 2 iterations), your recovery phrase (64 MiB, 3 iterations) and share codes. The recovery phrase setting matches the memory and iterations of the RFC's second recommended option. |
| RFC 5869HMAC-Based Key Derivation Function (HKDF) | HKDF-SHA-256 derives each vault's sub-keys from its 32-byte vault key. |
| RFC 2104HMAC: Keyed-Hashing for Message Authentication | HMAC-SHA-256 binds your stretched passcode to the device key on your phone. |
| BIP39Mnemonic Code for Generating Deterministic Keys | The word list behind your 12-word recovery phrase: 128 bits of entropy, in the same standard crypto wallets use. |
| Apple Platform SecurityKeychain Data Protection | How iOS protects Keychain items. On iPhone and iPad, HypaVault's device key is a Keychain item for this device only, kept out of iCloud and computer backups. |
| Android DevelopersAndroid Keystore System | How Android keeps key material non-exportable. On Android, HypaVault's device key is wrapped by a non-exportable Keystore key, in StrongBox when the phone has it. |
What Stays Private
What HypaVault knows about you is short: what you bought, and nothing you stored.
Setup Is Just a Passcode
You never give HypaVault an email, a phone number or a sign-in. Your passcode and recovery phrase are the only keys.
Your Files Stay on Your Phone
Nothing you store reaches Cyberdunes. The app's interface makes no network calls of its own, and your backups go only where you save them.
Purchases, and Only Purchases
The App Store or Google Play takes the payment. RevenueCat receives the store's record of the purchase and an anonymous ID, never vault content, names or personal details. The App Store label reads Data Not Linked to You: Purchases, Identifiers.
What It Can't Protect
HypaVault protects what's inside a locked vault. It can't protect copies you take out, a phone that's already compromised, or a vault whose passcode and recovery phrase are both lost.
Copies You Take Out
Sharing a file out of the vault hands over a decrypted copy. Photos you import stay in your gallery, and any cloud photo backup, until you delete them there.
A Compromised Phone
Malware, or someone watching while the vault is open, can see what you see. Anyone with your recovery phrase can open your backups. On iPhone, apps can't block screenshots.
Losing Both Keys
Lose both your passcode and your recovery phrase, and the data is gone for good. Nobody can recover it, including us.
Encryption You Can Carry
Download HypaVault for iPhone, iPad or Android and every file you add is encrypted on your phone from the first one.
Questions About Security
How the encryption works, what it protects, and what no vault on your phone can protect.
Every file is encrypted on your phone with AES-256-GCM before it's saved. Each vault has its own random 256-bit key, and every file has its own key too.
Read the Help ArticleIt's stretched with Argon2id and bound to a device key in your phone's secure storage. After 5 wrong tries the lock screen waits 30 seconds, doubling after each miss, up to an hour.
Read the Help ArticleNo. On iPhone it's a Keychain item for this device only. On Android it's wrapped by a non-exportable Android Keystore key. Neither is in iCloud, computer or Google cloud backups.
Read the Help ArticleNo. The phone always holds four identical-looking key slots, used or not, so without a passcode there's no list, count or name of vaults anywhere.
Read the Help ArticleNo. We never receive your keys, passcode or recovery phrase, so we can't open your vaults, reset your passcode or bring back anything lost.
Read the Help ArticleThe app's interface makes no network calls of its own. The only outside service is RevenueCat, for purchases, and it never sees your vaults.
Read the Help ArticleOn Android, yes: screenshots and screen recordings of the app show black. iPhone doesn't allow apps to block screenshots, so HypaVault covers itself in the app switcher and while the screen is recorded or mirrored.
Read the Help ArticleCopies you share out of the vault, malware on the phone, or someone watching while the vault is open. And if you lose both your passcode and your recovery phrase, nobody can get the data back.
Read the Help Article