Zero-Knowledge Proof of Existence

Prove the file existed before you shared it
Without Uploading Them.

Hash a file privately in your browser, then keep a timestamped certificate with the work. Your file never leaves your device.

SHA-256 · Local Browser Hash

e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855

File stays on your device — only the hash is transmitted
RFC 3161 Compliant
Blockchain Anchored
Zero Upload
Open Standards

How It Works

Three steps. A cleaner record.

01

Hash Locally

Your file is hashed with SHA-256 directly in your browser using WebAssembly. The file never leaves your device.

SHA-256 · WASM
02

Timestamp the Hash

The hash is sent to a timestamp authority, creating independent evidence that this exact fingerprint existed at that time.

RFC 3161 · TSA
03

Keep the Certificate

You get a PDF certificate and verification link. OpenTimestamps adds a public blockchain anchor once the proof confirms.

Blockchain · OTS

Features

Proof habits that do not get in the way.

Your File Stays Private

Your file is hashed in the browser. Provelio receives the SHA-256 hash, not the file itself, so confidential drafts, demos, designs, and source archives stay on your device.

PDF Certificates

Every proof generates a downloadable PDF certificate with the hash, timestamp details, and verification link in one place.

Blockchain Anchoring

Proofs are anchored via OpenTimestamps, giving you an independent public timestamp in addition to the certificate.

Instant Verification

Anyone can verify a certificate by dropping in the original file. No account required.

Developer API

REST API with API key authentication for products, release workflows, document systems, and internal tools.

Bulk Timestamping

Upload many files at once. Each is hashed locally and timestamped independently for a cleaner project record.

Simple Pricing

Start free. Scale when ready.

30 free proofs every month — no credit card required. Need more? Creator and Pro plans are there when the habit sticks.

30
Free Proofs / Month
Hash only
Sent to Provelio
RFC 3161
Timestamp Standard
OTS
Public Anchor

Use Cases

Who it's for

Creators

Musicians, designers, writers — prove your work existed before you share it with the world.

Institutions

Schools, universities, exam boards — attest document authenticity at scale with tamper-proof records.

Businesses

IP departments, legal teams, R&D labs — timestamp intellectual property before disputes arise.

When to Use It

Use it before the file leaves your hands.

Before a Client Review

Timestamp the design export, deck, or draft before sending it. Keep the certificate with the brief and delivery email.

Before a Demo or Submission

Timestamp the song demo, manuscript, script, game build, or pitch deck before it goes to collaborators or reviewers.

Before an Internal Handoff

Timestamp source zips, invention notes, contracts, or generated documents before they move between tools or teams.

FAQ

Common questions

Make the record before the share.

30 free proofs every month — no credit card required. Start with one file that actually matters.