Name: Tokentag
Brand: Tokentagged

The Digital Twin

Your certificate offers more than just text: Add 3D models (calculated from photos or uploaded yourself), videos and images to tell the full story behind every work.

Does it work with an iPhone? Do I need an app?

Yes. Swap Cards and Tokentags work with NFC-capable iPhones and Android smartphones directly in the browser – no app to install, the web app opens automatically in the browser when you tap. To read, hold the card or tag to your phone; the matching page on tokentagged.com opens. For verifying, handing over and sending, the browser talks to the chip: on Android via Chrome, on the iPhone via Safari or Chrome. Desktop PCs have no NFC function; there you can only view certificates and balances.

What do I need to use tokentags?

An NFC-capable smartphone (iPhone or Android) with internet access – no app to install: the web app opens automatically in the browser when you tap and shows the associated digital certificate on tokentagged.com. To verify the signature or create a certificate you also connect your own Ethereum wallet holding a little ETH for the network fee; the chip communication runs through Chrome on Android and through Safari or Chrome on the iPhone.

Can a Tokentag be removed and attached somewhere else? What happens if it gets damaged?

A Tokentag should be attached so that it cannot easily be removed – on the back of a painting, for example, or with screw or rivet mounting on other objects. The chip confirms its own authenticity and its link to the certificate; the firm attachment, the photos and details stored in the certificate and the documented chain of ownership establish that chip and object belong together. If the chip is damaged it cannot be repaired and its key cannot be recovered. The certificate on the blockchain remains, but it can no longer be verified with that chip.

What happens to my certificate if Tokentagged should ever cease to exist?

The certificate does not live on our servers but as a token on the Ethereum blockchain. Images and descriptive data are additionally stored on Arweave when the certificate is created – a decentralised network for permanent storage. Both remain in place independently of Tokentagged and can be viewed with common wallets and blockchain explorers. Checking a Tokentag does not need any data from our servers either – everything required is public: the chip’s signature, the certificate on Ethereum and the manufacturer attestation. The Swap Card’s key is generated in the chip and never leaves it – the card remains a standalone Ethereum wallet even without our website. tokentagged.com merely provides the web app; any other app could perform the same check. An offline version of the web app, also to be stored on Arweave, is in progress.

Can I upload my own 3D models?

Yes. Besides calculating a model from photos, you can upload a finished 3D model – as a mesh (glb, gltf, obj, fbx, stl, ply or zip with textures) or as a Gaussian splat (ply, spz, splat, glb), up to 200 MB. After the upload we prepare the model automatically (size, orientation, preview and trailer); it then appears in the certificate and in the media slider just like a calculated model. All you need is a Tokentagged account, and you confirm that you own the rights to the model; no 3D voucher is needed and the upload is currently free of charge. In your project choose “New 3D model” → “Upload your own 3D model”.

How difficult is it to copy or counterfeit tokentags?

The security of the Tokentags relies on security chips that have proven themselves in bank cards and authentication systems. The secret key is generated inside the Tokentag, stored only there and never leaves it – not even we as the manufacturer know it. Cloning a Tokentag would mean extracting this key from the chip, which is exactly what the chip is built to prevent (Common Criteria EAL 6+). A copied print or a written-down number therefore does not help forgers. The check happens right in the browser: it gives the chip a fresh challenge, the chip signs it, and the browser compares the result with the address in the certificate – no central key on a server.

Chip & certification

Secure element NXP SmartMX3 P71 with JCOP 4 (Java Card); platform certified to Common Criteria EAL 6+. The same chip as in the Swap Card.

Curve & signature scheme

ECDSA on secp256k1 – the same curve and signature format (r, s, v) as Ethereum. The challenge is hashed with the Ethereum prefix (EIP-191).

Key generation

The key pair is created inside the chip; programming only reads out the public key. The chip additionally stores two attestations (card, manufacturer) and returns them with every check.

Verification flow

Challenge-response in the browser: a fresh challenge (when signed in, bound to the current block hash) is signed by the chip; the browser recovers the address (ethers.js) and compares it with the address in the token ID – no server request. The attestations are checked against the manufacturer address.

Anchoring

Certificate = ERC-1155 token in the “Tokentagged” contract on Ethereum; the chip address is part of the token ID. The contract verifies chip signatures itself (ecrecover) – when minting and optionally as a verification record on the blockchain (verifyTokentag).

Media storage

Images and description data (token metadata) are stored on Arweave, a decentralised storage network, when the certificate is created – retrievable even without Tokentagged.

Independence

Certificate (Ethereum) and media (Arweave) live outside our servers. Verification needs no data from our servers – everything required is public: chip signature, certificate on Ethereum, manufacturer attestation. tokentagged.com merely provides the web app; any other app could perform the same check. An offline version of the web app, also to be stored on Arweave, is in progress.

NFC & browsers

Android: Chrome (Web NFC); iPhone: Safari or Chrome (WebAuthn). No app to install – the web app opens automatically via the NFC link.

3D formats

Calculated from 20–200 photos or uploaded as your own model: glb, gltf, obj, fbx, stl, ply, zip; splats as ply, spz, splat – up to 200 MB.

Developed in Germany

Developed in and shipped from Germany (Lueers Inventions GmbH, Apelern).

Documentation

To the documentation

Authenticity and provenance – proven with a tap. The digital certificate of authenticity for art and valuables.

How it works

Attach the Tokentag

Tap and connect your wallet

Describe your work

Create the certificate

Show more

3D model

Images

Videos

Authenticity checked by phone

Certificate on the blockchain

No app to install

Verifiable worldwide

Copy-protected

For artists, collectors and dealers

The chip signs for itself

No central key

Works even without us

Speaks Ethereum’s language

For artists

For collectors

For dealers & small brands

Copy-protected Digital Certificate

Digital Twin & Multimedia

The Digital Twin

Royalties on resales

No hurdles (no app to install)

The Digital Twin

Blockchain

The King

The Bubble

The Night Meal

The Toad

The Mermaid

Certified security chip

Key is created in the chip

Runs on Ethereum

Company based in Germany

Buy Tokentags

Chip-secured

Support

Verifiable worldwide

Authenticity and provenance – proven with a tap.
The digital certificate of authenticity for art and valuables.