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UN Crypto Stamp

The United Nations Postal Administration pairs physical postage stamps with digital collectibles issued on Ethereum. Collectors can claim, hold, and transfer the digital collectible, with ownership recorded publicly on the network.

180k physical stamps issued across two series, each with a claimable digital counterpart on Ethereum

Digital collectibles · United Nations

Institutional context

The United Nations Postal Administration (UNPA) uses stamps to communicate the UN’s work and priorities to collectors around the world. The Crypto Stamp project extended this activity into digital collecting: each physical stamp could be paired with a collectible that people could own and exchange on Ethereum.

Developed with the United Nations Office of Information and Communications Technology, the project put blockchain into use within an existing UN service. It also formed part of UNPA's broader effort to modernize its stamp program and engage new audiences.

The first series was issued on 24 November 2020 through the New York, Geneva, and Vienna offices. A second series followed on 18 November 2022.

System design

Each physical stamp carries an identifier and a secret code concealed beneath a scratch-off panel. The code allows its holder to activate one corresponding digital stamp. Claiming the digital stamp requires a digital wallet and funds to pay the network fee.

The system does not create a separate Ethereum record for every unclaimed stamp. Instead, it stores a single verification record that can later be used to confirm whether a particular stamp was among those issued with a digital collectible. This reduces the amount of data that needs to be stored on Ethereum.

After activation, the digital stamp can be transferred separately from the physical stamp. The holder can send it to another person’s compatible digital wallet, with the change in ownership recorded on Ethereum.

Ethereum’s role

A smart contract on Ethereum records the issuance, ownership, and transfer of the digital stamps. Smart contracts are programs on Ethereum that carry out functions according to rules written into its code. Because ownership is recorded publicly on Ethereum, it can be checked independently rather than relying solely on a UNPA customer account.

The project uses ERC-721, an open standard for individually identifiable digital assets. Using a common standard allows compatible software and services to recognize the digital stamps.

UNPA remains responsible for issuing and selling the physical stamps, while the digital stamp can move separately between collectors.

Status and milestones

  1. 18 November 2022

    UNPA issued its second Crypto Stamp series in 2022, with an announced print run of 90,000 physical stamps paired with digital collectibles.

  2. 24 November 2020

    UNPA issued its first Crypto Stamp series in 2020, pairing physical postage stamps with digital collectibles issued on Ethereum. The announced print run totaled 90,000 physical stamps.

Implementation considerations

The scratch-off code needs to remain private until the digital stamp is claimed. Buyers also need to distinguish ownership of the physical stamp from ownership of its digital counterpart, particularly when buying either item secondhand.

Security of the digital wallet used to hold the collectible, transaction fees, and access to compatible software affect the collecting experience.

Sources