SHA256
https://sha256algorithm.com/
Solidity Re-Entrancy
https://solidity-by-example.org/hacks/re-entrancy/
https://quantstamp.com/blog/what-is-a-re-entrancy-attack
https://medium.com/coinmonks/reentrancy-exploit-ac5417086750
Timelock Attack
https://blog.openzeppelin.com/bypassing-smart-contract-timelocks/
Remix IDE
https://remix.ethereum.org/#optimize=false&runs=200&evmVersion=null
