'How to Solve the Ethernaut Game's Level 5: Token' by Kamil41492605 solidity smartcontractssolidity
// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; contract Token { mapping balances; uint public totalSupply; constructor public { balances[msg.sender]=totalSupply=_initialSupply; } function transfer public returns { require; balances[msg.sender] -=_value; balances[_to] +=_value; return true; } function balanceOf public view returns { return balances[_owner]; } }
To hack this contract first you need to understand the concept of integer underflow and overflow. The overflow is a situation when uint reaches its byte size. Then the next element added will return the first variable element.Let me explain with an example. Note: The hardhat console library is necessary to log to the console in Remix.
If you run this code in Remix, be sure to use compiler version 0.6. As you can see we have a variable named decrease with value a 0. If we subtract 1 from that variable we end up with 255.
Norge Siste Nytt, Norge Overskrifter
Similar News:Du kan også lese nyheter som ligner på denne som vi har samlet inn fra andre nyhetskilder.
How to Get Your Personal Website to the Next Level | HackerNoonThe portfolio, in a sense, is a longer version of a Resume. In modern times, it’s important to showcase your work by uploading your portfolio to a website.
Les mer »
Shiba Inu Whales Control 26% of Total Supply of Token: Here's How It Might Be BullishICYMI: $SHIB whales that control 26% of the supply are facing $100 million worth of profit ShibaInu SHIB
Les mer »
How to Build a Decoupled Microservice Using Materialize | HackerNoonOne way to handle data in microservice architectures is to use decoupled microservices architecture. This form of architecture can bring many benefits.
Les mer »
How to Write Better Tests and Prevent Flaky Tests | HackerNoonFlaky tests ruin the development experience. In this article, we will talk about how to avoid creating such tests.
Les mer »
Build a Single Page Web3 App with Vue 3, Vite and Pinia | HackerNoonA complete how-to guide on creating, testing, and deploying an example bookstore application with Vue 3, Vite, Pinia, Nightwatch
Les mer »
What is the Best Pokémon Fusion? | HackerNoonIn this slogging thread, the gaming community discovered a website where we could experience Pokémon fusions, and we discussed which one was the best.
Les mer »