Certificates of authenticity

Every work on ChainChum, physical or digital, has a certificate of authenticity, recorded as an NFT on a public blockchain. Originals and numbered prints are certified when they are published, handmade goods and downloads when each one sells. The seller's one-time $1 certificate fee comes out of the work's first sale; from then on every sale, resale and inheritance through ChainChum is added to it for free. It records who made the piece, what it is and who owns it, and it stays verifiable for as long as the piece exists.

#What is on a certificate

• The artwork's photo, title, medium, size and edition number.
• The artist's name and shop.
• The date it was issued and a unique certificate ID.
• A QR code that opens the certificate's verify page.
• A content hash: a fingerprint of the work's details and photos. If anything about the record changed, the fingerprint would no longer match.

#Verifying a certificate

Scan the QR code or open chainchum.app/c/<certificate-id>. The verify page recomputes the content hash and shows the piece's history: when it was listed, sold and, later, resold or inherited. Anyone can verify a certificate; you do not need an account.

#Printed certificates and the free QR code sticker

The PDF certificate comes with every piece at no extra cost. For an original or a numbered print you can also add a printed certificate ($14.99) at checkout, where it is offered:

• printed on heavy cotton paper once the certificate's record is anchored, and posted to you;
• with two free QR code stickers in the same envelope: tamper-evident labels for the back of the piece or its frame. Scanning one opens the certificate with "This sticker belongs to this certificate"; if anyone peels it off, it shows VOID.

Your order page shows when it is being prepared and when it is posted, with the tracking number. If the order is refunded, both stickers read as void.

#Your collector name

Certificates say "a ChainChum collector" for whoever holds them. In Me › Profile you can choose a collector name instead, like "The Okafor collection", shown on the certificates you hold for public pieces. It is off unless you turn it on, and you can change or remove it at any time.

#Giving a piece to someone

Once a piece has arrived and settled for 14 days, you can give it, with its certificate, from My collection › Gift. Enter their email and an optional note, check the details, and send the offer. They sign in or create an account with that email (ChainChum is for adults: 18 or over) and accept or decline within 14 days; you can withdraw the offer until then. When they accept, the certificate shows them as its holder and its history shows the gift. No one else can open the gift link.

#When a detail on a certificate was wrong

If the artist made a mistake in the title, medium, year or size, they can propose a correction. As the holder you see the old and new details side by side in My collection and choose Agree (your certificate gets the corrected details under the same code) or Keep it as it is. Nothing changes without your answer, and the earlier version stays in the certificate's public history. In rare cases ChainChum corrects a certificate directly, and both the artist and the holder are told why.

#Is the certificate an NFT?

Yes. Each certificate is a standard ERC-721 token on Base, a low-cost Ethereum network. ChainChum mints it when the seller publishes the work, transfers it to the buyer when the piece sells, and pays the network fee each time. Read more in NFT certificates of authenticity and What is an NFT?.

#Do I need a crypto wallet?

No. The original ChainChum asked everyone to install MetaMask or Coinbase Wallet. The new ChainChum keeps a wallet for every owner and a public record of every certificate on a blockchain behind the scenes, so the proof does not depend on us, but you never handle keys, coins or fees.

If you already use a wallet and want to hold your piece's token yourself, an export to your own wallet option will be available under your certificates. Once exported, the token can be moved or traded on other NFT marketplaces like any ERC-721 token; such a transfer shows on the verify page as off-platform until the new holder claims it. ChainChum itself never buys, sells or trades tokens, and certificates are never for sale here.

Never share a wallet recovery phrase or private key with anyone. ChainChum will never ask for one.

#What a certificate does not do

A certificate proves the record of a piece: who made it and who owns it on ChainChum. It does not replace insurance or a professional appraisal, and holding a token is not the same as holding the physical piece.