KarmaGangChallenge

This repository is an implementation of the following challenge: https://twitter.com/karmacoma_eth/status/1475283580121010176

Solution

How to be cool?

To be cool the address interacting with the KarmaGang contract must start with 0xc0de42. This kind of addresses can be created using CREATE2.

How to be a MagicERC20?

MagicERC20 should show balance increasement between calls in the same transaction. So, an idea to implement this is to use gasLeft() because this value decreases during the transaction execution. The current implementation returns 10**77 - gasLeft() that should be an increasing value.

How to be definitelyNotContract?

To make a valid submission to KarmaGang contract the address interacting with it should be previously registrered via register() function. Only the addresses without code are marked as definitelyNotContract. As we need a MagicERC20 contract as the caller to submit the registration, it will only work if it is executed during the contract construction, i.e the contract constructor function should call the KarmaGang register function.

Extra details

Factory

• To use CREATE2 is necessary to deploy a factory contract

  Deployed Factory: 0xE5e5b7FfD841FFA05804368c0343A81132bD69aE

  You can learn more about this using the following repo: https://github.com/miguelmota/solidity-create2-example

E1Ru1oMagicERC20

• The contract implementation is the same one used in the challenge submission to match the bycode used in the deployment

  Deployment txn: 0x37504f317ae6a2d90b7efbd0cf0f0d221ecc7034c1b5f3c5624bc3200088dc24

• Line 24 is not needed, so it can be removed.
• The contract can be improved a bit parameterizing claim function to send custom submissions ;-P.

Compute the 0xc0de42 address

• Do all the changes you consider in the contracts.
• Deploy your factory.
• Set the the address of your factory in the factory variable in c0de42.finder.js#L6 script.
• Run the c0de42.finder.js script. (npm run address)
• Wait until the salt is found.

Challenge submission:

0x26c0006ba7985db0a6ad68399a39b404f909d4ebe56312e979624fa39080fd81