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Cost per timestamp ... sats

Stamp new document

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Loading network fees

Verify existence

1. Upload original file

2. Paste transaction id or load proof file

Verify digital signature

Verify that a digital signature corresponds to a bitcoin address and a specific hash

Or enter data manually

💡 Offline verification with bitcoin core

You can also verify signatures offline

bitcoin-cli verifymessage "<dirección>" "<firma>" "<hash>"

This will return true if signature is valid

About Time Stamping

This tool lets you digitally timestamp documents on the Bitcoin blockchain, providing irrefutable proof of their existence at a specific moment in time.

How does it work?

When you upload a file, its SHA-256 hash is calculated and included in a Bitcoin transaction. Once the transaction is confirmed, the hash is recorded on the blockchain, ensuring the document has not been altered since that moment.

🔑 Sign with a Bitcoin Key - Prove authorship

What is it for?

While a blockchain timestamp proves when a document existed, a digital signature proves who created or authenticated it.

How does it work?

  1. Click “Sign with Bitcoin key” before broadcasting the transaction
  2. Enter your Bitcoin private key (WIF format) or generate a new one
  3. The system signs the document’s SHA-256 hash with your private key
  4. The signature and your public Bitcoin address are stored in the proof file (.json)

Benefits:

  • ✅ Only you can create that signature (you hold the private key)
  • ✅ Anyone can verify you signed the document (using your public address)
  • ✅ The signature cannot be forged or altered
  • ✅ Independent verification: You don’t need this site to prove authorship in the future

🔒 Security: Your private key is processed only in your browser and is never sent to the server.

Verification

Verify existence on the blockchain: You can verify any timestamped document by uploading the original file and providing the transaction ID (TXID). The tool will check that the file hash matches the one recorded on the blockchain.

Verify authorship (digital signature): In the “Verify Signature” tab you can confirm a digital signature is authentic. You can also do this without the website using Bitcoin Core:

bitcoin-cli verifymessage "address" "signature" "hash"

Costs

The cost to timestamp a document is 1000 sats, plus Bitcoin network fees depending on the selected priority.

Signing the hash is completely free because it happens in your browser and requires no additional transactions.

Security and Privacy

Files you upload are not stored on our servers. Only the file hash is used to create the blockchain transaction. The document’s contents remain private.