We were finalists of the ETHGlobal London in March 2024. We turned every attendee’s wristband into a crypto wallet using account abstraction. https:/twitter.com/ETHGlobal/status/1769849042694025262

Problem

When you organize an event or manage a community space, it’s great to be able to give participants an NFC card, tag or wristband for access control. Wouldn’t it be cool if you could also use that NFC tag as a crypto wallet that people could easily top up and tap to pay?

Solution

With Account Abstraction, we can now turn those NFC tags into a wallet that can hold any asset. People can send tokens to their NFC tag and tap to pay at a series of whitelisted stations (to avoid abuse). It allows you to do simple transactions in stablecoins or any other token. It can be used at events such as ETHGlobal to manage payments and to allocate finite resources to make sure that these are distributed fairly (e.g. swags). It could also be used as a way to reward people (e.g. earn tokens by doing some actions at the event, tap your wristband to receive the tokens). Tokens can represent resources such as:

• Food
• Drinks (e.g. coffee machine)
• Meeting rooms
• Workshop access
• Print credits .. Next to the NFC Wallet, we implemented a native NFC payment terminal/PoS application (using Flutter) that can easily withdraw assets from the NFC wallet. For security reasons, the withdrawal devices must be whitelisted to withdraw funds from the cards.

ETHGlobal London implementation

Original repo from the hackathon can be found here https://github.com/citizenwallet/ethglobal-london-app. You can find a blog post about our participation here; https://paragraph.xyz/@citizenwallet/citizenwallet-team-ethglobal

Progress post-hackathon

We use the same tech to power the crypto bar at the monthly Crypto Wednesday event in Brussels. https://twitter.com/citizenwallet/status/1780237580107128881 We also developed a faucet for people to receive tokens by tapping their NFC wallet on a device (https://github.com/citizenwallet/faucet-app). We used that to onboard people to a new local currency in a commune of Brussels called the WOLU (https://www.linkedin.com/feed/update/urn:li:activity:7185899878613417984/)

We are also going to power the CELO Gather conference in Berlin May 24 https://www.celodao.eu/gather.

Next steps

We plan to continue the development of the NFC wallet in the near future as we see clear applications for the technology. For future development, we focus on features to ease onboarding and to be able to easily integrate with shops to accept NFC payments.

The city of Woluwe-Saint-Pierre in Brussels is interested in offering NFC wallets to their citizens to support a local community currency that rewards civic engagement.

Within the scope of upcoming projects, we plan to focus on the following developments:

• Further development of a PoS application for merchants to accept payments.
• Improve the web app for user to easily see their balance and top up their NFC wallet.
• Integrate the NFC wallets into the Citizen Wallet app to be able to link the NFC wallet with your smartphone to be able to also do mobile transactions
• Set up some experiments to integrate with the PoS backend of merchants

Plans for Funding

We are in the process of requesting a subsidy from the region of Brussels to develop a local payment network using NFC wallet. We are working on commercial partnerships to offer NFC wallet to events.

Team Members

• Xavier Damman - Core developer: https://www.linkedin.com/in/xavierdamman/
• Kevin Sundar Raj - Core developer: https://www.linkedin.com/in/kevin-sundar-raj-92261b33/
• Jonas Boury - Project and product developer: https://www.linkedin.com/in/jonasboury/