The guide

Your files stay with you.
Their proof can travel.

DfinA Vault lets you fix the exact content of a file, its date and, with a seal, its origin. The action is simple: choose or capture a file, certify it, then keep or share the certificate.

✓No file sent ✓No account required ✓Any digital format
Local computation The fingerprint is created in your browser. The file doesn’t leave.
DfinA Vault
What? When? Who?

Certify a file

Choose an existing file or capture a photo or video directly.

Choose a file Document, image, video, audio, ZIP…
Photo Video
Your file never leaves this device.
Verifiable certificate A PDF, a QR code and a fingerprint to check any copy.
The principle

One file, three simple questions.

DfinA Vault doesn’t judge your document. It fixes three technical markers around it, without ever receiving its content.

What?

The cryptographic fingerprint represents the file’s exact content. A single change, however small, produces a different fingerprint.

Integrity byte by byte

When?

The certificate ties a date to this fingerprint. With Premium, this date gets an independent anchor in the Bitcoin blockchain.

Verifiable time marker

Who?

The personal seal links a series of files to a single stamp that its holder can reproduce and prove they control.

Continuity of origin
Privacy by design

The system’s strength also lies in what it doesn’t receive.

Your document stays on your device. The browser computes one-way fingerprints. DfinA Vault therefore cannot read your file, restore it, or disclose it.

Local fileThe content stays on the phone or computer.
Two fingerprints, computed on the spotSHA-256 and SHA3-512, two different cryptographic families.
A certificate to keepYou stay in control of your files and your proofs.
Use cases

DfinA Vault in real life.

Short scenarios, sector by sector: what certification is for, concretely.

Respect for your privacy. Videos load only when you click "play". Until you start one, no data is sent to YouTube.

Other situations

Artist

You timestamp a creation before releasing it.

WhatWhen
Dive center

You seal your clients’ dive logs.

WhatWhen
Teacher

You certify every communication sent to families.

WhatWhen
Photographer

You prove that a photo came first.

When
Property inspection

You lock in a property’s condition at the handover of keys.

WhatWhen
Contract

A single version is authoritative, recognized by all parties.

WhatWho
Association

You archive your minutes, dated and attributed.

WhatWhenWho
The whole chain: @dfinavault →

These scenarios are in English for now. For French- and Korean-speaking audiences, we’ll add subtitles or dedicated versions.

The journey

Certify in a few steps.

Select each step to see what happens. The cryptographic complexity stays in the background.

Step 1

Choose what you want to fix.

Any digital file can be selected. On mobile, the camera also lets you document a situation the very moment it happens.

MP4etat-des-lieux-sortie.mp4Video captured on the phone · 148 MBReady
●Tip: always keep the original file. A compressed or re-exported version is no longer strictly identical.
Step 2

Two fingerprints, computed on your device.

The same file always produces the same fingerprints; the slightest change — a comma, a pixel, a cut in a video — changes them entirely. DfinA computes two, from different cryptographic families (SHA-256 and SHA3-512), for a proof that stays robust over time.

#SHA-256 fingerprintLocal computation complete100 %
a4b8e4d19c76290f0b914f0a6a39e27e769f3db44142c941735f94bd6f6c218a
#SHA3-512 fingerprintSecond family · local computation100 %
3475b03986d6da033e3bcc554b88af1920c9b91845043dfe282ae4858437375b3c545fc737b81db094a33024aca38928ab241868c31bcd3dbd46dbccca9dbdee
●Privacy: a fingerprint cannot reconstruct your document.
Step 3

Essential is enough for most uses.

Essential combines integrity and a DfinA date. Premium adds an independent time anchor on the Bitcoin blockchain, useful as a second assurance for more sensitive or longer-lasting matters.

Essential

Integrity + DfinA date. Simple, immediate and suited to everyday use.

Premium

Essential + proof of anchoring on the Bitcoin blockchain, verifiable without relying on DfinA.

●Keep in mind: Premium isn’t necessary for every file. It mainly strengthens the date’s independence and durability.
Step 4

The seal adds a recognizable origin.

In the unlimited plans, a personal stamp can be embedded in the certificate. Its secret passphrase stays solely in your hands and lets you reproduce the same pattern.

SEAL · PRO
8F2A-71C9-5D04
Public pattern, secret seal passphrase.
●Important: back up your seal passphrase. DfinA cannot recover it.
Step 5

Your proof is ready to live alongside the file.

Keep the certificate, attach it to the document, share it by messaging, or bundle everything into a ZIP archive with a summary and instructions.

PDFcertificat-dfina-vault.pdfQR code · fingerprints · date · optional seal✓
●Good practice: place the original file and its certificate in the same folder or archive.
Always available

On mobile, DfinA Vault becomes a field reflex.

The PWA can be installed like an app. You open the tool from your home screen, capture a situation and create its proof without any complex software.

Certify this photoThe file stays on this phone
Film and certifyIdeal for an inspection, a worksite, a handover
Add DfinA Vault to your home screen

Capture at the right moment

Take a photo or film directly from the interface when a situation deserves to be documented.

An app-like experience

The PWA opens from an icon, full screen, without going through the browser’s bookmarks each time.

The same privacy principle

Capture and computation are local. Mobile use doesn’t change the rule: your file is not sent to DfinA.

Share immediately

The certificate or archive can be sent from the phone’s share menu to your email, your cloud or a contact.

Installation in under a minute

Install DfinA Vault like an app.

No app store, no complex download. Choose your device and follow three steps.

1
Open DfinA Vault in ChromeGo to dfina.org/vault.
2
Tap the ⋮ menuTop right of the screen.
3
Choose "Install app"Or "Add to Home screen", then confirm.
DfinA Vault appears on your home screen.Then open it like any other app.
The richness behind the simplicity

A simple action, but several levels of use.

For an occasional user, one file and one certificate are enough. For regular subscribers, DfinA Vault becomes a real workshop for preparing, certifying and sharing.

Unlimited plans

Certify a multitude of files in a single pass

Select several files and let the tool produce the proofs without manually repeating the same journey for each one. A decisive feature for client files, photo series, deliverables or archives.

Personal seal

Affix a recognizable stamp

The seal adds the "Who?". The visible pattern can accompany your creations, deliverables or communications, while the phrase that reproduces it stays secret.

SEAL · DFINA
3C91-A04F-77B2
A consistent origin across an entire body of work.
Learn more about the seal
One button

Create a ZIP archive ready to send

Bundle the files, the certificates, a readable summary and a verification how-to. The recipient gets a coherent set rather than a scatter of separate pieces.

Sharing

Share according to the context

Send just the certificate, the file with its proof, the QR code or the full archive. The right option depends on what the recipient needs to view or verify.

A dual time assurance

Premium adds a date independent of DfinA.

All certificates already have a DfinA date. The Premium option anchors the fingerprint in the Bitcoin blockchain using an open protocol. The document itself is never published there.

1. Your file

It stays on your device.

2. Its fingerprint

A string of characters, not the content.

3. Collective anchoring

The proof joins a batch of fingerprints.

4. Bitcoin blockchain

A public and independent date.

What this adds

A proof of time anchoring that can be verified independently, including with open tools and without relying on the service’s survival.

What this doesn’t change

You don’t buy any cryptocurrency, you have no wallet to manage and your file is not published on the blockchain.

Understand anchoring on the Bitcoin blockchain
How to choose: use Essential as your everyday habit. Reserve Premium for files where the date’s independence, the retention period or the stakes justify this second assurance.
The check

To verify is to compare the received file against the proof.

A certification doesn’t stop someone from altering a copy. It makes that alteration immediately detectable.

The certificate provides the reference

Fingerprints, date, identifier, QR code and, where applicable, seal and Premium proof.

The file is recomputed locally

DfinA Vault recomputes its fingerprint then compares it with the one on the certificate, without sending the file.

✓ Exact match: file unchanged
In practice

Verify in two drops.

Scan the certificate’s QR code, or drop the certificate in box1

Drop the file to check in box2

You’ll immediately know:

✓your file is identical
✓your certificate is authentic (No., date and time)
✓the seal is valid, if any
Batch verification

Check a multitude of files in a single pass too.

For a complete folder, no need to start over file by file. Load the batch’s reference fingerprints, select all the files to check and get a separate result for each one.

1Load the batch referenceCertificates or manifest supplied with the archive.
2Select all the filesThe computations stay on your device.
3Read the summary immediatelyMatching, missing or modified.
Folder verification12 / 12 matching
PDFcontrat-final.pdf✓ Identical
JPGphoto-01.jpg✓ Identical
MP4constat-video.mp4✓ Identical
ZIPlivrables.zip✓ Identical
No file sent · local comparison

Three smart ways to share

A precise promise

Understand what the proof says, and what it doesn’t.

Trust comes from an exact wording. DfinA Vault greatly strengthens the clarity of a file, but doesn’t replace the relevant institutions or professionals.

What DfinA Vault establishes

  • ✓That a file presented today is strictly identical to the one matching the certified fingerprint.
  • ✓That a specific fingerprint existed at a given date.
  • ✓With the seal, that a single stamp recurs across a series of files and that its holder can prove control of it.
  • ✓With Premium, that an independent time anchor was recorded in a public ledger.

What DfinA Vault doesn’t claim

  • !That the content of a photo, video or document is true, legal or accurate.
  • !That the user is the legal owner or author of the content.
  • !That the seal constitutes a legal identity or a qualified electronic signature.
  • !That a certificate replaces a notary, a judicial officer, a lawyer or a public authority.
The four habits

So a proof stays useful for a long time

Keep the originalA strictly identical copy is fine, but a re-exported or compressed version will no longer match.
Keep the certificateStore it with the file or use the ZIP archive prepared by the tool.
Back up the seal passphraseNo one can recover it. Losing it prevents reproducing the same stamp.
Document the contextA clear summary, explicit file names and folder metadata strengthen human understanding.
The DfinA Vault habit

When a file may matter tomorrow, fix its version today.

Start simply with one file. The seal, batch certification, the ZIP archive and Premium anchoring come in as your usage grows.

Certify a file See the official site