What is a certificate of authenticity? Paper vs digital

A certificate of authenticity is a document stating that one item is genuine and identifying it: what it is, who made it, and who is making the statement. It is also called a COA, a certification of authenticity, a letter of authenticity or an authenticity letter. The format runs from a signed card to a bound report, but the job is the same.

A certificate is a promise, not proof in itself. It is worth what its issuer is worth, and only while it stays with the item it describes. Paper certificates tend to fail on the second condition, and sometimes on the first.

There is no single legal template, but where the law does set one out, it asks for much the same things. California requires an art dealer selling fine prints, photographs or sculpture casts made in multiples to furnish a certificate of authenticity. It must disclose the artist, the artist's signature, the medium, whether the piece is a reproduction, when it was produced, the use of the plate and the number of pieces in a limited edition.¹

For autographed sports and entertainment memorabilia sold for $50 or more, California requires the dealer to give a written express warranty of authenticity, which may be part of the invoice. It must give the dealer's legal name and address, the date of sale and the price, describe the item and name the signer, and say whether the signing happened in the dealer's presence. It must also list the information the dealer relied on, any serial number that matches a number printed on the item, and whether the item came from a third party. The dealer keeps a copy for seven years.²

Taken together, a sound certificate of authenticity states:

• What the item is: a description, with the marks, materials and dimensions that tell it apart.
• A unique identifier, such as a serial or edition number, that matches one on the item itself.
• Who made it, and when.
• Who issues the certificate, how to reach them, and their signature.
• What the claim rests on: the issuer's knowledge as the maker, a witnessed signing, or an examination.
• For an edition, its size and this item's number in it.

Four kinds of issuer are common, and their certificates carry different weight.

In each case the certificate is a claim by someone about something. The further the issuer stands from the making of the item, the more the certificate rests on judgment rather than knowledge.

Paper has four weaknesses, and each matters more as an item's value rises.

• It can be copied. A good scan and printer reproduce most certificates, and a genuine certificate can be paired with a fake item.
• It can be lost or separated from the item. Once they are apart, nothing connects the two, and a replacement is hard to get.
• It stays the same when the item is resold. A paper certificate names the first buyer, if anyone, and says nothing about who owns the item now.
• It is hard to check on the spot. A buyer holding a certificate can rarely tell from the paper alone whether it is genuine, current, or about the item in front of them.

Holograms, seals and security paper make a certificate harder to copy, which is why a certificate of authenticity hologram is so common. Those parts are counterfeited too. In the global customs data of the Organisation for Economic Co-operation and Development (OECD) and the EU Intellectual Property Office (EUIPO) for 2020–21, 20% of seizures involved packaging, labels and other authentication components, such as holograms or QR codes. Counterfeiters ship them apart from the goods and assemble the fakes near the market.³

US customs data shows the same trade. In fiscal 2025, the top ten counterfeit commodities by quantity at US Customs and Border Protection (CBP) included 822,653 labels and tags and 4,206,696 items of packaging and boxes.⁴

A digital certificate keeps the same statements and changes what they are attached to. Instead of a document that travels beside the item, it is a record for that one item, opened by tapping a secure tag fitted in the item itself. The tag is what binds the record to the object.

ISO's guideline on authentication solutions for material goods, ISO 22383:2020, sets the aim as establishing a good's authenticity and integrity throughout its entire life cycle. A paper certificate speaks for one moment, the day it was issued. A digital certificate can be checked at every hand-off, and it can keep a record of each one.⁵

Three things follow. The record is per item, so two units of the same model each have their own. Ownership can transfer, so the certificate names the current owner rather than the first. And the record has a history: each scan, transfer and resale is added to it, so the certificate grows with the item instead of aging.

A secure tag also changes what copying achieves. It produces a fresh cryptographic code each time it is read, so a photo of the certificate or a forwarded link replays an old code and is not shown as verified. No identity system makes copying impossible, but a copy of the link is no longer enough to pass for the original.

Whether it is on paper or digital, a certificate that holds up does these things:

• Give each item a unique identifier, and put it on the item as well as on the certificate.
• Describe the item closely enough to tell it from others of its kind: materials, marks, dimensions and photographs.
• Name the maker and the date and, for an edition, its size and this item's number.
• Say who is issuing the certificate and what the claim rests on, and sign it.
• Keep your own register of every certificate issued, so a buyer can check one against it.
• Decide what happens on resale: who records the new owner, and how the next buyer checks the history.
• Bind it to the item where you can. A certificate opened from a tag in the item is far harder to separate from it than paper is.

Vera Certificates are digital certificates of authenticity bound to Vera Tags. For most brands, the tag goes in at manufacture: in a watch it sits inside, behind the dial. A box of tags can be bound to its products before it ships, so each item has its certificate from the factory, before the first sale, and keeps it through every owner after.

Take the Black Dive Watch from Maison Vera, the demo house on Vera's platform. Anyone can tap it to open its public certificate and see that it is authentic, on any phone, with no app. The certificate carries the brand's logo and colors. Ownership is recorded on it and travels with the watch, sale after sale, and it keeps the watch's ownership history from the brand through every owner since. Every scan is recorded with where it happened, and a copied link is recorded as an invalid scan rather than shown as verified.

Owners keep control. An owner can hold the certificate without their identity being shown, and share links can be revoked after they are sent. An owner can pass the watch on with a code, and on acceptance the ownership record changes hands. If the watch is reported lost or stolen, anyone who taps it afterwards sees that status. A watch and its strap can be handled as a group, one parent certificate with a child for each part. If a tag is damaged in a repair, it is replaced and the certificate is rebound, with its whole history kept.