Polygon for Developers – A Simple Guide with Video

What are Polygon and MATIC all about and why is another blockchain needed? You will find answers to these questions in this article. The article starts with problems plaguing Ethereum, workable solutions to the problem, and then dives into more details of the Polygon network, its history, tokenomics, and an overview of the Polygon SDK. … Read more

Smart Contract Replay Attack in Solidity

This is part 8 and a continuation of the Smart Contract Security Series. Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack This post provides insights into the replay attack in blockchains. As per the wiki, a replay attack is a valid data … Read more

Smart Contract Randomness or ReplicatedLogic Attack

This is part 7 and a continuation of the Smart Contract Security Series. Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack In this tutorial, the randomness attack or also called replicated logic attack is analyzed. The problem in Solidity contracts is finding … Read more

DelegateCall or Storage Collision Attack on Smart Contracts

The post is part 6 and continues our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack The DelegateCall attack or storage collision is expounded in this post. Before you can grasp this exploit, you must first understand how … Read more

Ethereum Smart Contract Fuzz-Testing with Echidna

What is Fuzzing?                 Fuzz testing (or fuzzing) is an automated software testing method with the goal to find vulnerabilities, security issues, and defects of the application. The idea is to inject invalid, malformed, or unexpected inputs into the application using a fuzzing tool and observing how the system reacts to those inputs (e.g., exceptions, leakage … Read more

Denial of Service (DoS) Attack on Smart Contracts

This post is part 5 of our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack The post discusses the Denial of Service or alias the DoS attack. The Denial of Service (hence referred to as DoS) restricts legitimate … Read more

tx.origin Phishing Attack — Smart Contract Security

This post is part 4 of our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack In this post, we discuss phishing attacks due to tx.origin. In the regular phishing of a website, phishing begins with a phony email … Read more

Reentrancy Attack – Hacking Smart Contracts [Solidity]

You can check out the code for this article on our GitHub. Preamble This post is part 3 in continuation of our Smart Contract Security Series. This post is part of our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack … Read more

Private Variable Exploit – Hacking Smart Contracts in Solidity

Introduction This post is part 2 of our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack In this part 2 of the series, we’ll examine how to exploit the “private” vulnerability in Solidity. As the name suggests, private … Read more

Ownership Exploit in Solidity Smart Contracts

In the smart contract security series, we will see multiple vulnerabilities, attacks, and exploitations in the smart contracts, along with the prevention measures. This post is part 1 of our Smart Contract Security Series: Ownership Exploit Private Variable Exploit Reentrancy Attack tx.origin Phishing Attack Denial of Service Attack Storage Collision Attack Randomness Attack Replay Attack … Read more

Creating an NFT Marketplace with Solidity and JavaScript

This tutorial shows you how to implement your own prototype of an NFT marketplace with Solidity and JavaScript. You can check out the code on our GitHub: GitHub: https://github.com/finxter/NFTMarketplace For additional help, you can find a full course with explainer videos on the Finxter Computer Science Academy: Video Course: Creating an NFT Marketplace with Solidity … Read more

Ethereum Smart Contracts and EVM

In the previous posts, we developed simple smart contracts, deployed them using Remix or Truffle, and interacted with them using JSON-RPC interface providers such as using web3.py or web3.js. In this post, we shall take a closer examination into how a smart contract works on the Ethereum blockchain at the grass root. More precisely, we … Read more