Third-Party Verification Guide

Who Is This Guide For?

This guide is for anyone verifying a TimeProof timestamp who is not the original creator — lawyers reviewing evidence, auditors checking compliance records, opposing counsel examining claims, insurance adjusters reviewing documentation, or any third party presented with a TimeProof certificate.

You do not need a TimeProof account, any software installation, or blockchain expertise.

What You Need

To verify a timestamp, you need at least one of:

The original file — the actual file that was timestamped (best option)
The SHA-256 hash — the 64-character fingerprint from the certificate
The transaction hash — the blockchain transaction ID from the certificate

With the original file, you can verify everything end-to-end. With just a hash or transaction ID, you can confirm the blockchain record exists but cannot confirm which file it corresponds to without the file itself.

Verification for Non-Technical Users

Step 1: Check the File Hash

If you have the original file and a TimeProof certificate, confirm they match:

Open any SHA-256 calculator online (search “SHA-256 file hash online”)
Upload or select the file
Compare the resulting hash to the hash on the certificate

If the hashes match, this exact file was timestamped. If they differ, the file has been modified since timestamping.

Step 2: Check the Blockchain

Open polygonscan.com — this is a public blockchain explorer
Paste the transaction hash from the certificate into the search bar
Confirm the transaction exists and shows “Success” status
Note the timestamp on the transaction — this is the moment the proof was recorded

The blockchain record is public. You’re looking at the same immutable database that stores cryptocurrency transactions for millions of users. No entity controls it.

Step 3: Confirm the Connection

For the proof to be valid, the file’s hash (from Step 1) must be connected to the blockchain transaction (from Step 2). For single-file timestamps, the hash appears directly in the transaction data. For batch timestamps, this connection is through a Merkle proof — a mathematical chain from the file hash to the recorded root hash.

The Merkle proof is included in the certificate or LG package.

Purchasing a Courtroom-Ready Package

If you need a formal evidence package for legal proceedings:

Visit app.timeprooflabs.com/verify
Upload the file or enter the hash
Confirm the timestamp exists
Click “Get Courtroom-Ready Package — $1.95”
Connect a wallet (Google or Apple login creates one automatically — no crypto needed)
Complete the Stripe checkout
Download the ZIP package

What’s in the Package

File	Purpose
`certificate.pdf`	Visual certificate for court submission
`certificate.json`	Machine-readable metadata
`merkle_proof.json`	Mathematical proof linking file to blockchain
`identity_attestation.jws`	Signed identity proof (if owner was verified)
`identity_readme.json`	How to verify the identity signature
`verification_guide.txt`	Plain English instructions for courts
`CHECKSUMS.sha256`	Integrity hashes of all package files

The verification_guide.txt is specifically written for non-technical reviewers. It explains every verification step in plain language suitable for court proceedings.

For Legal Professionals

Presenting Blockchain Evidence

When presenting a TimeProof timestamp in legal proceedings:

Provide the original file — the timestamped file itself
Provide the LG package — the seven-file evidence bundle
Reference the Polygonscan link — the public blockchain record
Explain the mechanism — “the file’s unique fingerprint was permanently recorded on a public blockchain at the stated time”

The LG package’s verification guide is designed to be included as an exhibit. It explains the verification process in terms accessible to judges and opposing counsel.

Independent Expert Verification

For contested claims, any expert can independently verify the timestamp:

Compute the file’s SHA-256 hash using standard cryptographic tools
Verify the Merkle proof mathematically (standard algorithm)
Query the Polygon blockchain directly (no website needed — any Ethereum node works)
Verify the identity attestation using TimeProof’s published public key

Every step uses open standards and publicly available data. There is no proprietary technology or secret sauce — the security comes from mathematics and blockchain immutability.

Chain of Custody

The LG package includes CHECKSUMS.sha256 — integrity hashes of every file in the package. Running sha256sum -c CHECKSUMS.sha256 confirms that no file in the package has been altered since generation. This supports chain-of-custody arguments for digital evidence.

For Auditors

Compliance Verification

When auditing timestamps for compliance purposes:

Request the original files and certificates from the organization
Re-hash each file and compare to certificates
Spot-check transactions on Polygonscan
For LG timestamps, verify identity attestations against the public key

Bulk Verification

For auditing many timestamps at once, consider using the TimeProof API:

POST /api/verify — verify a file hash against blockchain records
GET /api/verify/check/:hash — quick hash verification

See Verification API Endpoints for details.

Key Concepts for Non-Technical Reviewers

Concept	Plain English
SHA-256 hash	A unique fingerprint of a file. If the file changes even slightly, the fingerprint changes completely
Blockchain	A public database that no one controls. Records cannot be changed or deleted after they’re written
Merkle proof	A mathematical chain that connects a specific file’s fingerprint to the recorded proof on the blockchain
Polygonscan	A website where anyone can look up blockchain records — like a public courthouse database
JWS attestation	A digitally signed statement that can be verified using a published public key — like a notary seal that anyone can check

Verifying a Timestamp — technical verification walkthrough
Polygonscan Verification — using the blockchain explorer
Legal-Grade Package Guide — what’s in the evidence bundle
Verification Page Guide — using the online verification tool