Every feature, and the technology behind it
J-Vault is built for people who need to keep things private today and prove them years from now. Here is what it does and how, so you can judge it for yourself.
Privacy by design
Your vault is locked before it leaves your hands
Encryption happens on your device. What reaches our servers is unreadable without keys that only you and your trusted devices hold.
On-device encryption
Every photo, title and diary line is encrypted inside your browser with AES-256-GCM before upload. The server receives ciphertext only.
AES-256-GCM · Web Crypto API
A key nobody else holds
Your Master Data Key is created on your device and kept non-extractable inside an isolated Web Worker. Not even the page itself can read its raw bytes.
Non-extractable CryptoKey
Recovery Kit
Eight words, delivered as a PDF, open your vault on any new device. They are stretched with PBKDF2-HMAC-SHA256 at 600,000 iterations, the level OWASP recommends.
PBKDF2 · 600,000 iterations
Trusted devices
Sign in with Google and a trusted device opens the vault directly. Each device holds half of a split secret and a private signing key that cannot be copied off it.
Split secret · ECDSA P-256
New computer? Use your passkey
Add a passkey once and any new computer opens with Google sign-in plus your passkey. Without a passkey, a new device, cleared browser data, a removed device or 90 days without use ask for your 8 words. Add an optional PIN; five wrong tries erase that device's half of the secret.
90-day device expiry
My Key Was Exposed
If someone saw your words, generate a new key in Settings. Every record is re-encrypted on your device and the old key is published as revoked.
Key rotation + public revocation
Proof that holds up
A receipt, a chain and a Bitcoin anchor for every record
Saving is easy. Proving is the hard part. J-Vault records evidence about each record at the moment it arrives, so the proof exists long before anyone asks for it.
Salted fingerprint
Each record gets a fingerprint built from a random salt, the date you state and a hash of the content. It commits to the content without revealing it.
leaf = SHA-256(salt | date | payload hash)
Personal hash chain
Every new record is linked to the one before it. Removing or reordering history breaks the chain, and the break is visible.
SHA-256 hash chain
Signed receipt
The server signs the fingerprint, the arrival time and the chain position with its Ed25519 key. Anyone with the public key can check the signature.
Ed25519 · RFC 8032
Hourly Bitcoin anchoring
New chain links are combined into a Merkle tree every hour, and its root is timestamped on Bitcoin through OpenTimestamps. Delays over 48 hours are flagged with the exact hour count.
Merkle tree · OpenTimestamps
Two dates, never mixed
Every record shows the Document/Event Date you state and the Vault Ingress Timestamp the server recorded. You describe the past honestly; the system records the present precisely.
User-stated vs server-recorded
Deleted, but history stays honest
When you delete a record, its content is wiped at once and its receipt stays in the chain, so nobody can quietly rewrite your timeline.
Tombstone records
Evidence Packs
Share proof that checks itself
Select the records you want to disclose. J-Vault builds a print-ready dossier with reference codes, both dates, the receipts and a QR code to a live verification page. Print it, save it as PDF or send the file.
- The reader drops the file on the page and its SHA-256 is compared byte for byte
- Each receipt, chain link and Bitcoin anchor is checked live
- You choose what to disclose; everything else stays encrypted
- Included in your plan, with one free pack during the trial
| Reference Code | REC-4F9A2C |
| Document/Event Date (User-Stated) | 12 March 2019 |
| Vault Ingress Timestamp (Server-Recorded) | 2026-11-08 14:02 UTC |
| Ed25519 receipt | ✓ VALID |
| Date sealed at ingress | ✓ MATCHES |
| Bitcoin anchor | ✓ Confirmed |
Capture and diary
Made for real paperwork on a real phone
Book page mode
High-contrast grayscale for printed text, books and typed letters. Pages land at about 60 to 80 KB and stay sharp to read.
Medical and color mode
Keeps the colors of reports, scans and prescriptions at about 120 to 180 KB.
Legal and stamp mode
The full page in color plus a lossless close-up of the signature, thumbprint or seal you select. Always under 280 KB in total.
Save now, tag later
Share a photo straight into J-Vault from your Android gallery, or tap once on iPhone. Add a title and category whenever you like.
Private diary
Short notes or long memories, sealed the moment you save them. A record of events written as they happen.
English and Urdu
The full interface works in English and in Urdu (Nastaliq, right to left). Recovery words can be English or Urdu, and common spelling variations are understood.
Backups and freedom
Your records never depend on us
Master Capsule
Export your whole vault as one encrypted HTML file, split into 20 MB volumes. Keep copies with people you trust.
Offline Vault Opener
A separate single-page opener reads any capsule without internet, even in airplane mode. Add it to your home screen.
Leave whenever you want
Export at any time. If your plan ends, your records stay readable and exportable. There is no lock-in.
Under the hood
The technology, in plain sight
Standard, published building blocks, put together carefully. No secret methods to take on faith.
| Encryption | AES-256-GCM in the browser's Web Crypto API, with each ciphertext bound to its own record so files cannot be swapped on the server |
|---|---|
| Key derivation | PBKDF2-HMAC-SHA256 with 600,000 iterations and a random 128-bit salt, followed by HKDF-SHA256 to separate the encryption and login keys |
| Key handling | Non-extractable keys inside an isolated Web Worker; raw key bytes never reach the page |
| Trusted devices | 256-bit secret split in two halves, plus an ECDSA P-256 device key stored non-extractable in IndexedDB |
| Receipts | Ed25519 signatures (RFC 8032) over the fingerprint, arrival time, chain position and chain hash |
| History | Per-person SHA-256 hash chain; deleted records keep their place as tombstones |
| Timestamps | Hourly Merkle batches anchored to Bitcoin through OpenTimestamps calendars |
| Evidence Packs | SHA-256 fingerprint of the exact file registered at issue; live verification page |
| Web security | Strict Content Security Policy, no third-party scripts, HTTPS with HSTS, CSRF protection |
| Payments | Bank transfer or mobile wallet; J-Vault never collects or stores card numbers |
Why serious buyers choose J-Vault
Eight reasons this is more than storage
Zero-knowledge by design
We built the system so we cannot read your records. The code enforces it, and the formulas are published.
Proof anyone can check
Receipts, hashes and the formulas behind them are printed in every Evidence Pack.
An independent clock
Bitcoin anchoring means even J-Vault cannot backdate a record without it showing.
Honest about limits
We label what you stated and what we recorded, and we flag delays instead of hiding them.
No lock-in
One-file backups and an offline opener that works without our servers.
No ads, no trackers, no data sales
Your subscription is our only income, so your data never has to be our product.
Rooted in verification work
J-Vault grew out of twenty years of news verification, where proving facts was the daily job. Read the story.
No card numbers stored
You pay by bank transfer or mobile wallet. J-Vault never asks for, sees or stores a card number.
See it with your own documents
Start free, save a real paper and open its receipt. Then decide.
Start free with Google14 days free. No card needed. Cancel anytime.