Verification Guide

How to Independently Verify a Proof Without EverCert

Your proof works without us. Here's how to verify it yourself using free, open-source tools.

Why Independent Verification Matters

The whole point of a Bitcoin-anchored timestamp is that it does not depend on any company — including EverCert. If EverCert were to disappear tomorrow, your proof would still be valid. The proof file contains everything needed for verification: the document hash, the Merkle path, and the Bitcoin block reference.

This is what separates blockchain timestamps from certificates issued by private services. A certificate from a company is only as trustworthy as the company itself. A Bitcoin-anchored proof is as trustworthy as the Bitcoin network — the most secure distributed system ever built.

Independent verification means you can prove the integrity of your document to anyone, at any time, without asking EverCert for permission or confirmation.

What You Need

  • •Your original file — the exact file that was timestamped (not a modified or re-saved version)
  • •The .ots proof file — downloaded from EverCert when the timestamp was created
  • •A command line terminal — Terminal on macOS, PowerShell on Windows, or any Linux terminal
  • •Python 3 — required to install the OpenTimestamps client (most systems have this pre-installed)

Step-by-Step Verification

1

Install the OpenTimestamps Client

The OpenTimestamps client is a free, open-source Python tool. Install it with pip:

pip install opentimestamps-client

This installs the ots command-line tool.

2

Compute the SHA-256 Hash of Your File

On macOS or Linux:

shasum -a 256 yourfile.pdf

On Windows (PowerShell):

certutil -hashfile yourfile.pdf SHA256

This produces a 64-character hexadecimal string — the file's unique cryptographic fingerprint.

3

Verify the .ots Proof File

Run the OpenTimestamps verify command:

ots verify yourfile.pdf.ots

If the proof is complete (Bitcoin-anchored), you'll see output like:

Success! Bitcoin block 880123 attests existence as of 2026-02-17

If the proof is still pending (not yet anchored), you'll see a "pending" message. Wait a few hours and try again — the proof upgrades automatically.

4

Compare the Hashes

Confirm that the hash from Step 2 matches the hash referenced in the .ots proof. If they match, the file has not been altered since it was timestamped. If they don't match, the file has been modified — the proof is only valid for the exact original file.

What Each Step Proves

  • •Computing the hash proves the file has not been altered since the timestamp was created. Any change — even one byte — produces a completely different hash.
  • •Verifying the .ots file proves the hash was anchored to the Bitcoin blockchain at a specific block height and time. The Merkle path in the proof connects your hash to the Bitcoin transaction.
  • •Together, they prove that this exact file existed at that exact point in time — and has not been modified since. This is proof of existence.

Quick Verification Using EverCert

If you prefer a visual interface, you can also verify proofs directly on the EverCert website:

  1. 1Go to evercert.io/verify
  2. 2Upload your original file or enter its SHA-256 hash
  3. 3View the verification result — including the Bitcoin block number, timestamp date, and proof status

Note: The EverCert verify page is a convenience tool. The CLI method above is the gold standard for independent verification because it does not rely on EverCert's servers at all.

Learn More

How It Works — Technical Deep-Dive →

SHA-256 hashing, Merkle trees, and Bitcoin anchoring explained.

Verify a Proof →

Use EverCert's built-in verification tool.

Timestamp a Document Now

Free. Private. No account required.