We desired to create decentralized QR-Code based AirDrops on real-life events with O(1) upfront transactions.
What it does
Allows anyone to print and gift QR-Codes with tokens locked inside each.
How we built it
We create angular-based dApp with Solidity smart contracts and proposed EIP-1837.
Challenges I ran into
Specially invented MerkleTree of addresses with truncated 160-bits hashes to protect from front-running attack and reduce QR-code size. See presentation slides.
Accomplishments that I'm proud of
First in the world decentralized QR-code AirDrops First EIP about redesigning Ethereum fees, which can work today for any miners
What I learned
Had 2 nights full of debugging Merkle trees and verifying signatures related issues :)
What's next for QRToken
Going to propose ETHGlobal sponsors to use this Dapp for upcoming hackathons and different real-world events.