Saving a proof to the blockchain

Saving a proof permanently, also called stamping, writes its fingerprint into a transaction on the DigiByte blockchain, as part of a batch. Once that transaction has enough confirmations, the proof is at Level 3: Stamped.

From then on the record does not depend on DigiStamp. The blockchain is kept by many computers around the world, and nobody can change or remove the transaction, including DigiStamp. Anyone can look it up in a block explorer.

• You are signed in with Digi-ID, as the proof’s owner.
• The proof is published. A draft cannot be stamped. See Drafts and publishing.
• You have DGB in a wallet for the stamp fee.

Signing is not required to stamp, but a proof that is both signed and stamped tells the most. See Signing with your wallet.

1. On the proof’s page, under Blockchain stamp, choose Get payment address. The proof gets its own payment address, shown with the amount and a QR code.
2. From your own wallet, send at least that amount to that address.
3. Wait until the payment has one confirmation. The page notices it by itself.

DigiStamp checks what the proof’s own address has received. Once that covers the fee with at least one confirmation, the stamp is queued. A payment counts only for the proof whose address it was sent to. If your wallet shows the payment but the page does not, you can also give the payment’s transaction ID; it counts only for what it paid to this proof’s address.

Once the payment is accepted, the proof’s stamp is Queued: it waits for the next batch. A batch combines the fingerprints of all the proofs in it, in pairs, into one Merkle root, and one DigiByte transaction anchors that root for the whole batch.

Each proof keeps its own Merkle proof: the few other fingerprints needed to rebuild the root from its own. With it, anyone can show that the proof’s fingerprint is in the batch, without trusting DigiStamp. The certificate shows the Merkle root and this inclusion path. How to check one is in Checking a batched proof.

The anchor is a DigiByte transaction with an OP_RETURN output, which carries data and no coins. DigiStamp pays its network fee. Its data is the text prooflink.digistamp.co:b: followed by the 32 bytes of the batch’s Merkle root.

Nothing else about the proof goes on the chain: not its title, description, text, file name or signing address.

Each block added to the chain after the one that holds the transaction is one more confirmation. While the batch is waiting, the proof’s stamp status is Pending, and its page shows the batch, the anchor transaction and its Confirmations as a count of the 6 this site requires. You can close the page; DigiStamp keeps checking in the background.

Fee payment

Counts at one confirmation.

Anchor transaction

Counts as permanent at 6 confirmations on this site.

When the anchor reaches them, the stamp status becomes Confirmed and the proof becomes Level 3, Stamped. Its certificate then says Anchored on chain, checked against the chain itself each time the certificate is opened.

• Queued: the proof is waiting for the next batch. Batches are sent by a background job, so this can take a little while.
• A broadcast that did not go out: if the batch’s transaction definitely was not sent, its proofs go back to the queue for the next batch by themselves. The fee you paid still counts; there is nothing to pay again.
• Pending for a long time: if DigiStamp cannot tell whether a batch’s transaction was sent, the team reviews it by hand before anything is sent again, so the same proofs are never anchored twice.

If a stamp seems stuck, contact the team and quote the proof’s ID and your payment’s transaction ID.