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
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
If you are considering investing time in learning about blockchain, it can seem a weighty undertaking. There are a multitude of blockchain variants such as Bitcoin, Ethereum, Litecoin, and Dogecoin, and the terminology can be just as confusing. Four general types of blockchain networks are in use today: public, private, consortium, and permissioned. Each has … Read more
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
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
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
This article will look at deploying a smart contract to Polygon using Brownie. What is Polygon? Polygon is “a protocol and a framework for building and connecting Ethereum-compatible blockchain networks” (https://polygon.technology/). It started as Matic Network in 2017 to solve Ethereum’s scalability and user experience issues by using an off/side chain scaling solution. In 2021, … Read more
An array is a data structure where multiple values of similar data types can be stored. In contrast, a struct works as a container of a group of elements of different data types. A struct can then also be considered as a new data type. Hence we can create an array of structs comprising those … Read more
What is an ERC-721 Token? An ERC-721 token is a smart contract on Ethereum that implements the methods and events specified in the EIP-721: Non-Fungible Token Standard. It is designed to be used as a non-fungible token (NFT), meaning the token’s instances (or units) are distinct from one another. The ERC-721 standard is based on … Read more
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
Deleting an element from an array in solidity can be an easy job, but some tricky parts lie under the hood. We use the “delete” function to remove the element from an array in solidity. But the length of the array and its sequence may not remain in the way we are expecting. Let’s go … Read more
What is an ERC-20 token? An ERC-20 token is a smart contract on Ethereum that implements the methods and events specified in the ERC-20 standard. It is designed to be used as a fungible token, meaning each instance (or unit) of a token has the same value as another instance of the same token. It … Read more