Note
If you are new to the field of information technology, taking our Introduction to Information Technology and its Career Roadmaps and Introduction to Cloud Technology with DevOps, Docker and Kubernetes (free self-paced) courses is highly recommended. Also, for a comprehensive coverage of blockchain concepts and its use cases, taking our Introduction to Blockchain Technology course is highly recommended.
Recap
In our previous article (How Digital Signature Works In Blockchain), we learned about the mechanism behind Digital Signatures and what role they play in a blockchain system.
In this article, we learn about the role and types of consensus algorithms that are widely used in the blockchain applications.
Anatomizing a blockchain consensus mechanism
A fundamental problem in large-scale distributed systems is how to achieve overall system reliability in the presence of failures. Systems need to be fault-tolerant. This requires a process for distributed, often heterogeneous systems to reach a consensus and agree on the network state, whether it is a database commit or an action to take. In this article, we will make an introduction to consensus algorithm in blockchain, followed by two separate articles covering two types of consensus algorithms, Proof-of-Work (PoW) and proof-of-stake(PoS) in depth.
One-to-One Live Blockchain Classes
Coding Bootcamps school offers One-to-One Live Blockchain Classes for Beginners.
What is consensus?
Consensus in a blockchain is the process by which a network of mutually distrusted nodes reaches an agreement on the global state of the chain of blocks. In blockchain, transactions or data are shared and distributed across the network. Every node has the same copy of the blockchain data. Consensus allows all of the network nodes to follow the same rules to validate transactions and add new blocks to the chain, and therefore allows it to maintain uniformity in all of the copies of a blockchain.
Sometimes, it is also called a consensus mechanism or consensus algorithm. A consensus mechanism focuses on the process and approach of how to reach an agreement. A consensus algorithm is a formal procedure or computer program for solving a consensus problem, based on conducting a sequence of specified actions. It is designed to achieve reliability in a network involving multiple nodes. Consensus algorithms ensure that the next block in a blockchain is fully validated and secured. Multiple kinds of consensus algorithms currently exist, each with different fundamental processes. Different blockchain platforms may implement different consensus mechanism. In this article, we will focus on the following two popular algorithms, show how they work, and discuss the pros and cons of each mechanism:
- PoW: This consensus algorithm was introduced by Satoshi and commonly adopted by many other blockchains, including Ethereum. The PoW is the mining process with the purpose of finding an answer to a cryptographic hashing problem. To do so, the miner has to follow the block selection rules to locate the previous block and use the hash from the previous block header, together with the Merkle root of current transactions in the new block, to solve the hashing problem. It requires considerable computations and hashing power. In Bitcoin, block selection rules that specify the longest chain wins.
- PoS: This consensus algorithm aims to select miners based on the various combinations of random selection based on the miners’ wealth or age (the stake). Instead of miners competing to solve energy consuming cryptographic hash functions, the network will instead use a pool of validators. Validators are nodes that are willing to stake their cryptocurrency on the blocks of transactions that they claim should be added to the public blockchain.
Next Article
Congratulation! We now successfully finished our first article series. In our second article series, we gradually move on to Ethereum blockchain development by covering the following 9 articles:
- Review of Architecture and Components of Ethereum
- How Ethereum Manages Accounts
- How Ethereum Manages Transactions
- How Smart Contracts Work in Ethereum
- How Ether and Gas Work in Ethereum
- How Ethereum Virtual Machine works
- How address and wallet work in Ethereum
- How mining works in Ethereum
- List of Tools and Technologies in Ethereum Ecosystem
This article is written in collaboration with Brian Wu who is a leading author of “Learn Ethereum: Build your own decentralized applications with Ethereum and smart contracts” book. He has written 7 books on blockchain development.
Resources
Free Webinars on Blockchain
Here is the list of our free webinars that are highly recommended:
- Hyperledger Fabric for system admin versus developers
- How to harness blockchain for environmental and corporate sustainability
- Review of Initial Coin Offering, Security Token Offering and asset tokenization use cases and best practices
- Hyperledger Fabric Deployment on Cloud
- Hyperledger Fabric for entrepreneurship- 21 blockchain business use cases
Free Courses
Here is the list of our 10 free self-paced courses that are highly recommended:
- IT Career Roadmap Explained
- Web Design with Bootstrap
- User Experience Best Practices
- Intro to Search Engine Optimization
- Web Design with WordPress
- Introduction to Drupal CMS
- Intro to Joomla CMS
- Intro to Cybersecurity
- Introduction to Cloud Technology
- Recorded Live Webinars and Classes
Self-Paced Blockchain Courses
If you like to learn more about Hyperledger Fabric, Hyperledger Sawtooth, Ethereum or Corda, taking the following self-paced classes is highly recommended:
- Intro to Blockchain Technology
- Blockchain Management in Hyperledger for System Admins
- Hyperledger Fabric for Developers
- Intro to Blockchain Cybersecurity
- Learn Solidity Programming by Examples
- Introduction to Ethereum Blockchain Development
- Learn Blockchain Dev with Corda R3
- Intro to Hyperledger Sawtooth for System Admins
Live Blockchain Courses
If you want to master Hyperledger Fabric, Ethereum or Corda, taking the following live classes is highly recommended:
- Live and self-paced blockchain development with Ethereum
- Live and self-paced blockchain development with Hyperledger Fabric
- Live and self-paced blockchain development with Corda
- Immersive Blockchain Bootcamp with live and self-paced courses
- Live crash course for learning Ethereum with Solidity
- Live crash course for building DApps with Hyperledger Fabric
- Live crash course for building DApps with Corda
- Live full-stack blockchain development in Hyperledger and Ethereum
Articles and Tutorials on Blockchain Technology
If you like to learn more about blockchain technology and how it works, reading the following articles is highly recommended:
- History and Evolution of Blockchain Technology from Bitcoin
- Overview of Blockchain evolution and phases from Ethereum to Hyperledger
- Comprehensive overview and analysis of blockchain use cases in many industries
- Blockchain Crowdfunding Security Token or Initial Coin Offerings
- A beginner Guide to Blockchain Technology
- How Decentralized Peer-To-Peer Network Works
- How blocks are added to the blockchain
- How Public and Private Keys of Cryptography Work
- What Is A Cryptographic Hash Function
- How Digital Signature Works In Blockchain
- The role and types of consensus mechanism in blockchain
- How Proof-of-Work Consensus Works in Blockchain
- How Proof of Stake Consensus works in Blockchain
Articles and Tutorials on Ethereum and Solidity
If you like to learn more about blockchain development in Ethereum with Solidity, reading the following articles and tutorials is highly recommended:
- Review of Architecture and Components of Ethereum
- Comprehensive Blockchain Ethereum Developer Guide from Beginner to Advance Level
- How to Write Ethereum Smart Contracts with Solidity in 1 hour
- Review of Architecture and Components of Ethereum
- How Ethereum Manages Accounts
- How Ethereum Manages Transactions
- How Smart Contracts Work in Ethereum
- How Ether and Gas Work in Ethereum
- How Ethereum Virtual Machine works
- How address and wallet work in Ethereum
- How mining works in Ethereum
- List of Tools and Technologies in Ethereum Ecosystem
- Review of challenges in distributed systems
- Review of Cap Theorem in Distributed Systems
- Horizontal Scaling versus Vertical Scaling in Distributed Systems
- How to Scale up Ethereum Blockchain Applications
- Review of scaling solutions for Ethereum
- How to Manage Ethereum State Channel with Raiden
- How Plasma Chains Work in Ethereum
- How Sharding and Gasper work in Ethereum
- How Proof-of-Stack Consensus Works in Ethereum
- A roadmap for Implementing Ethereum 2.0
- How to work with Decentralized Data and Content Storage in Ethereum
- How Decentralized Messaging with Whisper Works in Ethereum
- Review of Infura for Ethereum Development
- Review of Infura Ethereum API
- How to Use Remix with Infura for Ethereum Development
- How Ethereum Client API Works
- How Ethereum IPFS Storage Works
- How to Install and Start Ethereum IPFS Storage
- How to Run Ethereum IPFS Storage
- How to Work with Ethereum Swarm Storage
- How to Install Ethereum Swarm Storage
- How to Handle Ethereum Messages with Whisper
- Review of Popular Ethereum Smart Contract Libraries
- Review of Private and Permissioned blockchain
- How to Set up a Local Private Ethereum Blockchain
- How to Run Geth on a Local Private Ethereum Blockchain
- How to Build a Local Private Ethereum Blockchain with Mining
- How to Run Geth on a Local Private Ethereum Blockchain with Mining
- How to Create an Account on a Local Private Ethereum Blockchain
- How to Use Ethereum Optional Flags with New Chains
- Review of Ethereum Options for Development and Testing
- Review of Ethereum Developer Chain Options
- Review of Ethereum API and Console Options
- Review of Ethereum Networking Options
- Review of Ethereum Transaction Pool Options
Articles and Tutorials on Hyperledger Family
If you like to learn more about blockchain development with Hyperledger, reading the following articles and tutorials is highly recommended:
- Introduction to Hyperledger Architecture, Projects, Tools and Libraries
- Complete Review of Hyperledger Fabric Architecture and Components
- Hyperledger Fabric for System Administers versus Developers
- How to use Prometheus and Grafana to monitor Hyperledger Fabric
- Blockchain Developer Guide- How to Install Hyperledger Fabric on AWS
- Blockchain Developer Guide- How to Install and work with Hyperledger Sawtooth
- Blockchain Developer Guide- How to Install Hyperledger Burrow on AWS
- Blockchain Developer Guide- How to Install Hyperledger Iroha on AWS
- Blockchain Developer Guide- How to Install Hyperledger Indy and Indy CLI on AWS
- Blockchain Developer Guide- How to Install Hyperledger Seth and Docker on AWS
- Blockchain Developer Guide- How to Configure Hyperledger Sawtooth Validator and REST API on AWS
- Blockchain Developer Guide- How to Build Transaction Processor as a Service and Python Egg for Hyperledger Sawtooth
- Blockchain Developer Guide- How to Deploy Ethereum Smart Contracts with Hyperledger Burrow
- Blockchain Developer Guide- How to Create Cryptocurrency Using Hyperledger Iroha CLI
- Blockchain Developer Guide- How to Explore Hyperledger Indy Command Line Interface
- Blockchain Developer Guide- Comprehensive Blockchain Hyperledger Developer Guide from Beginner to Advance Level
- Introduction to Hyperledger Sawtooth Blockchain Development
Articles and Tutorials on R3 Corda
If you like to learn more about blockchain development on Corda , reading the following articles and tutorials is highly recommended:
Articles and Tutorials on Other Blockchain Platforms
If you like to learn more about blockchain development in other platforms, reading the following articles and tutorials is highly recommended: