In June 2019, Austrian Post started selling the world’s first blockchain stamp. The so-called Crypto stamps have been published with 150,000 of such stamps placed in circulation. The stamps have a nominal value of 6.90 € which is (was) also the official selling price.

Though the stamps are normal postage stamps, each stamp also has a digital counterpart. This digital counterpart of the physical stamp can be in five colours, each with a different degree of uniqueness: Red (1,500 pieces), Yellow (10,000 pieces), Blue (20,000 pieces), Green (40,000 pieces) and Black (78,500 pieces).

The Crypto stamp has a QR code and a visible printed code. With the help of this information, the digital counterpart of the stamp can be called up.

The colour of the digital counterpart to the physical stamp can be determined through the information printed on the stamp via a special section of the Austrian Post’s website (https://crypto.post.at/). In order to do this, one must either scan an individual QR code located on each stamp or enter the individual code visibly printed on each stamp on the Post website.

This is the digital counterpart of the physical stamp

It is also interesting that the first edition of Crypto stamps contains a limited number of items that cannot be purchased in normal retail stores or the online shop of Austrian Post. Instead, 500 crypto stamps are sold exclusively via the Austrian Post OnChain shop, which is based on a relatively innovative technology (namely smart contracts within the Ethereum blockchain). The first 401 Crypto stamps could be purchased in the OnChain-Shop (https://crypto.post.at/onchainshop) at a sales price of 6.90 €. However, the last 99 Crypto stamps of the OnChain shop will be sold according to a different price model by the Austrian Post. Their selling price increases by 8% after each sale.

In purely mathematical terms, this would mean that the last stamp of the OnChain shop would change hands for a retail price of 13.012,99 €.

Crypto stamp

Buyers of the normal version of Crypto stamps (i.e. stamps that can be purchased in retail stores or in the normal online shop) will receive a stamp with two scratch fields. Behind these scratch fields are individual access data to a digital wallet within the Ethereum block chain.

Image of a scratched Crypto stamp. The left part contains the postage stamp. The right part opens the way to a digital wallet. It contains an Ethereum address and a seed. With this information one gets access to an Ethereum wallet.

This wallet can be used with special browsers (e.g. Firefox and Chrome, after the browser plugin “Metamask” has been installed). If you just want to have a look into your wallet, you can enter the printed address on https://crypto.post.at/wallet. An unused wallet contains a small amount of the crypto currency ether (0.00166 ETH), which has a value of approximately € 0,35. The wallet also contains an individual token, which forms the technical basis for the digital counterpart. If you want to get a deeper look, you can enter the address on https://etherscan.io/.

The digital wallet has ether and an individual token on which the digital counterpart of the crypto stamp is based.

A closer look at this token reveals that it has a unique ID. Since the digital wallet and the token exist within the Ethereum blockchain, the entire life of the token can be publicly viewed. It is therefore possible to trace when the digital image was created by the Post Office, when the digital image was sold by the buyers of the stamp or when the Post Office sold the digital stamp in the OnChain shop. At this point, it must be noted that the sale of the physical stamp is not shown here.

If you take a closer look at the token IDs in the blockchain, you can see that 150,000 tokens were created. These have token IDs from 0 to 149,999. A closer search within the blockchain and in the crypto area of the post office reveals the following interesting findings:

The first Crypto stamp

The tokens with the ID 0–149,499 are assigned to stamps that are sold in the traditional way — i.e. via an online shop or in retail stores. The digital image of the first crypto stamp (token number 0) reveals that it is a digital stamp of the colour green and that the physical stamp has the code ‘3s3cZd’ printed on it.