Prove Your File Existed on a Specific Date

Create immutable blockchain proof that your document, image, video, or any file existed at a precise moment in time. No blockchain expertise required.

No blockchain expertise required.

Why Proving a File’s Existence Date Matters

Imagine you’re a photographer, and someone publishes your image claiming it’s theirs. Or you’re a songwriter, and a collaborator releases your unreleased track. Or you’re a researcher, and a competing lab publishes findings suspiciously similar to your unpublished data.

In every case, the question is the same: who had this file first?

Without proof, it’s your word against theirs. Courts, mediators, and platforms like Instagram or YouTube need something stronger than “trust me, I made this.”

That’s where timestamping comes in. A blockchain timestamp creates a permanent, tamper-proof record proving your file existed at a specific moment in time. Not because a company says so — but because cryptographic math and a public blockchain say so.

How Blockchain Timestamping Works

Here’s what happens behind the scenes when you timestamp a file with TimeProof:

Step 1: Your file gets a unique fingerprint

When you select a file, TimeProof runs it through the SHA-256 hashing algorithm — the same standard used by Bitcoin, Git, and TLS/SSL connections.

Think of it like a fingerprint: just as your fingerprint is unique to you, a file’s SHA-256 hash is unique to that exact file. Change one pixel in a photo, one character in a document, or one byte in any file — and the hash changes completely.

This is a one-way process. You can always compute the hash from the file, but you can never reconstruct the file from the hash. Your file’s contents remain completely private.

Step 2: The fingerprint goes on the blockchain

TimeProof submits your file’s hash to a smart contract on the Polygon blockchain. Polygon is a Layer 2 Ethereum network used by organizations like Aave, Uniswap, Stripe, and Reddit. It offers ~2-second block times and costs fractions of a cent per transaction.

The smart contract writes three things permanently:

Once written, no one can change or delete this record — not TimeProof, not any government, not anyone. That’s the fundamental property of blockchain: immutability.

Step 3: You get verifiable proof

If you ever need to prove your file existed on a specific date, you provide two things:

  1. The original file
  2. Your timestamp certificate (which includes the transaction ID)

Anyone can then:

If the hashes match, the file is mathematically proven to be identical to what was timestamped. No alterations, no tampering, no ambiguity.

What Makes This Different from Other Methods

”Can’t I just email myself a copy?”

This is the “poor man’s copyright” myth. Mailing or emailing yourself a file doesn’t create legally recognized proof of anything. Email dates can be manufactured, envelopes can be resealed, and no court treats self-addressed mail as reliable evidence. It has no legal standing.

”Can’t I just take a screenshot with a timestamp?”

Screenshots prove nothing — they can be edited in seconds. A screenshot of a calendar, a clock, or a file’s “Date Modified” property isn’t evidence. Any metadata examiner knows these fields are trivially altered.

”What about just saving the file and relying on the Modified Date?”

File system timestamps (Created, Modified, Accessed) are stored locally and can be changed with a single command. They’re not proof — they’re metadata that anyone with file access can alter.

Blockchain timestamping is different because:

For everyday protection, a standard timestamp gives you everything you need: a PDF certificate and direct Polygonscan link for independent verification.

But when the stakes are higher — a lawsuit, an insurance claim, patent defense, or regulatory audit — you want the Legal-Grade upgrade.

The Legal-Grade package adds the courtroom-ready layer on top of your standard timestamp:

The result is a self-contained evidence binder. Your lawyer doesn’t need to contact TimeProof. They don’t need special software. They follow the verification guide and confirm everything independently.

What This Costs

Protecting your files starts with one-time packs at $15 for 100 credits:

Pack credits do not expire, and TimeProof covers Polygon gas internally.

1

Select your file

Open TimeProof and drag your file onto the upload area. Your file never leaves your computer — the SHA-256 fingerprint is computed entirely in your browser.

2

Choose your timestamp type

Choose scheduled timestamps for 1 credit per file, or verified instant timestamps for 2 credits per file when you need immediate Polygon confirmation. Both create permanent proof.

3

Confirm and anchor

Click to timestamp. TimeProof computes the SHA-256 hash of your file and submits it to the Polygon blockchain. You pay zero gas fees — we handle that.

4

Download your proof

Receive a PDF certificate and direct Polygonscan link for independent verification, with verified identity and Legal-Grade evidence options available when needed.

5

Optionally upgrade to Legal-Grade

Add the verified Legal-Grade upgrade when you need the Courtroom-Ready PDF, JSON metadata, JWS identity attestation, and Complete Evidence ZIP.

What You Receive

Every Timestamp Includes:

📄

PDF Certificate

Readable proof showing the file hash, timestamp, and blockchain reference.

🔗

Polygonscan Link

Direct public verification of the on-chain anchor.

Verified Instant Timestamps Also Include:

Verified Identity Badge — Verified instant timestamps add an identity attestation badge to the certificate so reviewers can see the anchor came from a verified account.

Legal-Grade Upgrade Adds:

⚖️

Courtroom-Ready PDF

Presentation-ready evidence certificate for counsel, auditors, or formal review.

📋

JSON Metadata

Machine-readable timestamp data for technical or programmatic verification.

🔐

Identity Attestation (JWS)

Cryptographically signed proof that verifies through the public JWKS endpoint.

🗂️

Complete Evidence ZIP

Single download containing the core evidence package and bundled supporting proof materials.

The Complete Evidence ZIP bundles supporting proof materials such as the Merkle proof, verification guide, and checksums so third parties can review the package without contacting TimeProof.

Ready to protect your files?

Timestamp any file on the blockchain in seconds. Prove when it existed, prove it hasn't changed.

Try it — drop a file to see its unique SHA-256 fingerprint:

Drop a file here to see its SHA-256 hash

100% local — your file never leaves your browser

No blockchain expertise required.

Frequently Asked Questions

What types of files can I timestamp?
Any file type — PDFs, images (JPEG, PNG, RAW), videos (MP4, MOV), audio (MP3, WAV), code, spreadsheets, CAD files, 3D models, ZIP archives, and more. There's no restriction on file type.
Does my file get uploaded to your servers?
No. Your file never leaves your computer. TimeProof computes the SHA-256 hash (fingerprint) entirely in your browser. Only the 64-character hash string is sent to the server for blockchain anchoring.
How does this prove my file existed?
The SHA-256 hash is unique to your exact file — like a fingerprint. This hash is permanently recorded on the Polygon blockchain with a timestamp. To verify, anyone can re-hash your file and compare it to the on-chain record. If the hashes match, the file is identical to what was anchored at that time.
Is this legally admissible in court?
Blockchain timestamps provide strong digital evidence. The verified Legal-Grade upgrade adds the Courtroom-Ready PDF, JSON metadata, JWS identity attestation, and Complete Evidence ZIP for formal review under modern digital-evidence workflows.
What's the difference between Instant and Scheduled timestamps?
Verified instant timestamps anchor on the next Polygon block and consume 2 credits per file. Scheduled timestamps batch anchors during the low-gas window and consume 1 credit per file. Both produce permanent blockchain proof.

Related Pages

Protect your work in seconds.

Timestamp any file on the blockchain. No blockchain expertise required.

Built on Polygon SHA-256 Industry Standard Gasless — We Cover All Fees Legal-Grade™ Available