Blockchain / Frequently Asked Questions

What is the blockchain certificate of authenticity for?

When you purchase a Ulysse Nardin watch, we want to provide you with proof that your watch is genuine. To this end, we produce a certificate of authenticity in your name, protected by blockchain technology. This certificate may be useful in the event that you need to contact the after sales service, a dealer, or anyone you want to give the watch to, whether that is in the context of a gift, or a resale. With this digital certificate, you will no longer need to use the physical guarantee card provided with the watch, eliminating the risk of losing or forgetting it.

How to obtain a blockchain certificate?

To obtain a blockchain certificate, you must purchase a new Ulysse Nardin watch from the official retailer network, then register for the free extended warranty. You will then receive your certificate automatically and also be able to access your certificate from your customer account (on the future version of this website). Registration on the blockchain may take up to 24 hours from requesting the warranty extension to receiving your certificate.

How much does this blockchain certificate cost?

This certificate is free for anyone purchasing a new watch from our retailer network and requesting an extended warranty (also free).

Why blockchain?

Blockchain technology is used to create digital uniqueness. In this way, a digital document – in our case a certificate – becomes impossible to forge when it is protected on the blockchain. The blockchain makes it possible to create time-stamped attestations as proof that you purchased a genuine watch. The advantage of blockchain technology is that these attestations are digital; they can therefore be shared and stored online.

How can I check that a certificate is genuine?

We provide a certificate checker on our site. Simply dropping the document into the web page will allow you to verify that the certificate is genuine.

The following section is intended for anyone curious or with more advanced knowledge of blockchain.

Can you explain to me what a blockchain is?

Blockchain technology is used for storing information extremely securely. Thanks to the blockchain, data can be both public and forgery-proof, which represents a formidable tool for building trust in relationships between people. The blockchain was invented in 2008 by an anonymous person using the pseudonym Satoshi Nakamoto when they invented the peer-to-peer digital currency known as Bitcoin. Blockchain was originally used as a public transaction ledger allowing people using pseudonyms to trade with complete confidence. That’s how the Bitcoin blockchain arose and still endures today. The term blockchain is used to describe both the data and the protocol that stores this data. The term comes from the fact that data is organised in blocks linked to each sequentially using cryptography.

Which blockchain do you use?

We use the Bitcoin public blockchain. It is the longest-standing and most reliable thus far. It has been around for 10 years already and at this moment in time has never been hacked; it’s therefore the most secure. Other blockchains for protecting our certificates may have been less costly and faster , but we preferred the safest and most widely recognised solution. Furthermore, we make use of “scaling” thanks to the Woleet startup, which fits with our attitude towards environmental protection.

Why use a public blockchain?

There are various advantages to using a public blockchain:

• Maximum security thanks to considerable decentralisation
• And absolute transparency that makes the certificates externally verifiable.

It is thanks to the combination of these two elements that trust is created and our certificates are forgery-proof. All our certificates can be verified externally by us or by our provider Woleet , checking the Bitcoin blockchain itself (see section below on this matter). We strictly apply the blockchain principles of “decentralization” and “true ownership” to the basis of the revolution of trust provided by this new technology.

By which mechanism are certificates protected on the blockchain?

Each certificate is protected according to the following protocol:

1. The certificate is produced in PDF format
2. We create a hash of this certificate (hash = digital thumbprint, see section below)
3. We sign this hash with our Ulysse Nardin ID protected by an ssl certificate
4. We embed this signed hash in the Bitcoin blockchain;

to this end:

1. We send our hash to our partner Woleet by API , which maintains 100% confidentiality.
2. Woleet creates a Merkle tree with other details in accordance with the Chainpoint standard.
3. Woleet then saves the Merkle Root of this tree in a Bitcoin transaction.
4. Once the transaction has been approved, Woleet sends us back the Blockchain proof in Chainpoint format. We regard the transaction as approved when 6 blocks have been added to the Bitcoin blockchain after the block containing the transaction.

How can I verify the existence of the certificate in the blockchain for myself?

We use a standard format for the proof, known as Chainpoint

1. To obtain your blockchain proof in Chainpoint format, use your certificate checker, then click on “Download blockchain proof”, which you will receive in JSON format. This format is readable in some browsers by dragging and dropping into an empty tab or using a text editor.
2. The Bitcoin transaction ID is located under “anchors”: “sourceId”.
3. Using an online Bitcoin explorer, you can find the transaction as with https://btc.com/[transaction ID], then trace the Merkle Root in the output OP_RETURN.

Are my personal details well protected?

Yes, they are protected by various mechanisms. Firstly, only the hash for the certificate is sent to our provider, Woleet , so it cannot access the intelligible data. Secondly, we do not put the complete hash on the blockchain via the Merkle tree. It is therefore technically impossible to read the data contained in the certificate from the blockchain.

What is a hash?

A hash is a cryptographic means of representing numeric data in a unique way The hash for numeric data is said to be the equivalent of a digital thumbprint for a human. To obtain a hash from some data, we apply a hash function to the data.

Example Data to hash: “Hello world!”

Hash of the data: “c0535e4be2b79ffd93291305436bf889314e4a3faec05ecffcbb7df31ad9e51a”

This feature has various advantages, it allows:

• For quickly checking that the data is correct and has not been susbsequently altered
• Any type of data to be represented in a sequence of characters,

Example New data to hash: “Hello world !” Hash of the data: “341d44b969233a48baa4224043705f5bd32230fa0da370d234d7e3d4a73aa613” In this example, we can see that the new hash is very different from the one before, while being the same length.