Transcription below.

Welcome to BountyOne. This is our first webinar where we’re actually going to cover the hack that just happened with SpankChain, and how to avoid this happening to your own project and/or just contracts that you’re building for fun. So then, I’m sure you’ve heard in the news this week, SpankChain, they lost $40,000 in a hack. This was with their state channel smart contracts, there was a bug that allowed a random hacker to go in and actually drain the account. Thankfully it wasn’t too much. They did steal some ether, but it wasn’t millions of…


In this lesson we’re going to learn about ENS, or Ethereum Name Service, and how it helps us provide human-readable names for our dapps

ENS is a project within the Ethereum dev community who’s goal is to create a decentralized domain name registry for the decentralized web. Today, we use DNS servers to resolve our .com domain names to IP addresses. But a centralized name registry like DNS is vulnerable to spoofing and denial-of-service attacks. Since ENS is built on top of the Ethereum blockchain, it is decentralized and doesn’t suffer from the same vulnerabilities as DNS. ENS started out…


What is consensus on the blockchain? Consensus basically means that all nodes in a decentralized network must come to an agreement on what is the truth. For bitcoin, all nodes must agree on the transaction history. In a centralized system, all the participants trust that the authority will behave honestly and share the truth with the rest of the members. Since only the trusted party has the power to modify the data, it is straightforward to achieve consensus. Everyone simply accepts and believes what the central authority says. For example, you simply trust your bank will put the correct balance…


Join Jack as he walks you through the basics of Blockchain, and creating a simple Ethereum Dapp.

This is an archive of our live Coding the Blockchain workshop. For more information, learning, and live streams, check out https://blockgeeks.com/

Coding the Blockchain Pt. 2


We’re live! Join us as Niloo walks you through writing your first smart contract using Ethereum, as well as some examples like escrows and elections.

Be sure to stay until the end for a special promo code exclusively for our live viewers!


The term “cryptoeconomics” causes a lot of confusion. People are often unclear on what it is supposed to mean. The word itself can be misleading, as it suggests that there is a parallel “crypto” version of the whole of economics. This is wrong.

In simple terms, cryptoeconomics is the use of incentives and cryptography to design new kinds of systems, applications, and networks. Cryptoeconomics is specifically about building things.

Cryptoeconomics is not a subfield of economics, but rather an area of applied cryptography that takes economic incentives and economic theory into account. …


The most interesting part of Ethereum are smart contracts. You can think of smart contracts like autonomous agents deployed onto the Ethereum blockchain.

Smart contracts are made up of some data, as well as some code that manipulates that data. Just like a user account, smart contract accounts also have their own balance as well as a public address, which looks the same as the user account address.

To interact with smart contracts, you send transactions to it with some extra data, to specify which function you want to invoke, as well as any input parameters for the function…


In this lesson we’re going to see how to build a simple dapp using the Ethereum blockchain as our backend

We’re going to build a blockchain explorer, kind of like etherscan, but we’re only going to display the last 10 blocks on the chain. To do this, we’ll use an open-source framework called Ethers.io to quickly develop and deploy our dapp. Ethers comes with command line tools which are available as a node module and can be installed using npm install -g ethers-cli. Let’s install to our global context since we’ll probably use this across multiple projects. …


In this lesson, we’ll learn about building decentralized applications, or dapps. But first, let’s take a minute to appreciate the difference between dapps and regular web applications

In traditional web application architecture, there is a frontend client and a backend server. The frontend is written using HTML/CSS/JS and the backend is written in a framework of your choice like Rails, Node or Django. The front and backend interact with each other by sending JSON messages over HTTP. There is typically a hosting service where your backend would be running like AWS.

With decentralized applications, there is also a frontend…


In this video we are going to learn how to code up an election contract. We want to hold a free and fair election for a specified amount of time and only allow authorized people to vote in it.

We’ll start by defining a custom data type called a struct, which allows us to group together other data types, to define a Candidate struct. For a candidate in the election, we’ll keep track of their name and the number of votes they currently have.

Let’s also define a struct for the Voter, that will store whether or not the…

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