Zero-Knowledge Proof of Existence

Prove Your Files Existed.
Without Uploading Them.

Hash your files privately in your browser. Get a court-grade timestamp backed by the Bitcoin blockchain. Your files never leave your device.

SHA-256 · Local Browser Hash

e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855

File never leaves your device — only the hash is transmitted
RFC 3161 Compliant
Bitcoin Anchored
Zero Upload
Open Standards

How It Works

Three steps. Permanent proof.

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 Instantly

The hash is anchored to RFC 3161 Time Stamp Authorities, creating a cryptographic proof of the exact moment.

RFC 3161 · TSA
03

Anchor Forever

OpenTimestamps embeds the proof into the Bitcoin blockchain — an immutable, publicly verifiable record.

Bitcoin · OTS

Features

Everything you need. Nothing you don't.

True Zero-Knowledge

Your files are hashed entirely in the browser using WebAssembly. No file data is ever uploaded, transmitted, or stored on our servers. We prove existence without ever seeing the content.

PDF Certificates

Every proof generates a downloadable PDF certificate with embedded cryptographic evidence — ready for legal proceedings.

Bitcoin Permanence

Proofs are anchored to the Bitcoin blockchain via OpenTimestamps — immutable and independently verifiable by anyone, forever.

Instant Verification

Anyone can verify a certificate by dropping the original file — no account required. Cryptographic proof checked in seconds.

Developer API

REST API with API key authentication. Automate timestamping in your CI/CD pipeline, legal workflows, or custom applications.

Bulk Timestamping

Upload hundreds of files at once. Each is hashed locally and timestamped independently — perfect for large IP portfolios.

Simple Pricing

Start free. Scale when ready.

5 free proofs every month — no credit card required. Need more? Upgrade to Pro for unlimited certificates.

< 3s
Time to Create Proof
0 bytes
Data Uploaded
Bitcoin
Immutable Record
Proof Lifetime

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.

Trusted by Creators & Teams

Don't take our word for it.

"I timestamp every track before sending it to producers. Provelio gives me peace of mind that my work is protected, without uploading a single file."

SM

Sarah M.

Independent Musician

"We issue hundreds of certificates each semester. The bulk timestamping and API integration saved our registrar team hours of manual work."

JL

Dr. James L.

University Administrator

"Our legal team needed tamper-proof timestamps for R&D documentation. The Bitcoin anchoring makes these proofs independently verifiable — exactly what we needed."

PK

Priya K.

IP Counsel, Tech Startup

FAQ

Common questions

Your next idea deserves proof.

5 free proofs every month — no credit card required. Upgrade when you're ready.