One of the greatest features of the blockchain is that data are immutable. That means that nobody can change the content of any transaction without invalidating the whole blockchain. But unfortunately, there are several issues with this system: When you deploy your smart contract, you can’t change the code afterwards…

Your good developer habits are leading you to write inefficient smart contracts. For typical programming languages, the only costs associated with state changes and computation are time and the electricity used by the hardware. However, for EVM-compatible languages, such as Solidity and Vyper, these actions explicitly cost money. This cost…

At a recent Ethereum event, Vitalik Buterin provided suggestions for what to build next. Here is the source tweet — https://twitter.com/TheCryptoClimax/status/1565275354679627777 In this thread, we’ll explore what some of these mean. 1) Wallets using ERC-4337 ERC-4337 is a proposal aimed at account abstraction that would help make wallet design innovations easier and more practical. …

What if users could get rewarded for transactions and not pay gas? This tutorial will show you how! — How cool would it be if the users of your dApp did not need need to pay gas for transactions? What if they received rewards instead? MASS-ADOOOOOOOOOPTION! Here’s what we’ll cover In this tutorial, you will learn how to create dApps that support Meta-transactions and how to implement a Loyalty program to reward users…

It is not possible to access an external server from within a smart contract. Thus, it is not possible for the EVM to directly notify external applications about the occurrence of some event. That’s why there are events in Solidity. It is information issued within contracts and has two purposes…

Step by Step Guide For Building A Blockchain With Substrate — Hi there, today we’re going to learn how you can build your 1st blockchain with Substrate. If you haven’t read my previous story on the Overview of Substrate. Go ahead and read this for a better understanding of the Substrate platform. What is Substrate? The substrate can be described as a blockchain framework…

When a smart contract is created on an EVM-compatible blockchain, a location for its state variables is readily allocated. For state variables with a fixed size, it is easy to understand that the EVM can identify the necessary size to do so, but in the case of variables with dynamic…

For use with NFT Smart Contracts and Minting dApps Overview The methods I suspect most individuals are aware of for handling a presale/allowlist are through an array (expensive!), a Merkle Tree (rigid and painful), or the EIP-712 standard. The steps below outline an alternative approach through the application of coupons /…

Tornado Cash is a service on the Ethereum blockchain (and on a couple other networks) that allows users to deposit Ether or tokens and hide the source of the funds with the power of modern cryptography; users can deposit funds and then withdraw them to make it impossible to connect…

Executing complex functions on chain Ethereum has always been a big no-no, something that you should never do. Blockchain computation is very expensive as all the nodes are needed to execute the same calculation to verify its correctness. StarkWare is one of the Ethereum scaling services that is attempting to…

ZK-SNARKs are used to preserve privacy, including some of the non-obvious tricks like how to prevent double-spending. — In his tweet, Vitalik advised his subscribers to pay attention to the ZK-SNARKs technology, let’s take a closer look at how everything works. Some ways to use ZK-SNARKs for privacy Special thanks to Barry Whitehat and Gubsheep for feedback and review. ZK-SNARKs are a powerful cryptographic tool, and an increasingly important part of the applications that people…

Effective key management is one of the core challenges of blockchain adoption among enterprises. Every blockchain transaction relies on the unconditional secrecy of the private key. A compromised key can lead to permanent financial losses as well as legal and regulatory ramifications. …

Offline transactions are needed when we do not want to share our private keys with the ethereum’s node (geth). We shall see how to create raw transactions in go using modules given in go-ethereum for three scenarios Send balance to a given account Deploying a contract Transacting a contract function. …

The process. Over the last week, I dived head first into blockchain technologies and spent some time learning more about smart contracts and d-apps by replicating previously-realized projects to help me build my skill set. But now, time to take it to the next level: Come up with a project…

I know this one has been done — particularly line-by-line analyses of the Bored Ape Yacht Club (BAYC) smart contract. However, after reading some of these posts, I was still confused on the mechanics—let’s say I want to make a BAYC-styled NFT project. What do I actually do once I…

Checks, Effects, and Interactions (CEI), Mutex, Pull Payments, and Gas Limits are all effective techniques to prevent reentrancy attacks. — Reentrancy is a programming technique in which a function execution is interrupted by an external function call. Within the the logic of the external function call are conditions that allow it to recursively call itself before the original function execution is able to complete. Repeatedly re-entering a process to execute…

In Solidity, sometimes you need to add a big amount of data to the smart contract. Adding a big amount of data costs a lot of gas and hence sometimes is not possible to do. For example, you need to whitelist thousands of users or add thousands of addresses into…

The nonce is an important part of EVM accounts. Know how it is managed — Have you ever been greeted with the following error when sending a web3 transaction in Node? replacement fee too low [ See: https://links.ethers.org/v5-errors-REPLACEMENT_UNDERPRICED ] or the tx doesn’t have the correct nonce. account has nonce of: 95 tx has nonce of: 94 This implies that your transaction contains a nonce…

Whenever you are writing smart contracts in Solidity, you must be cognizant of how your variables and data are handled by the EVM. The choices you make will influence, among other things, gas costs — to call your functions or deploy your contract — as well as storage layout. Given…