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.
In our previous article (How blocks are added to the blockchain), we covered how a new block of data is added to the blockchain and how records stored in a blockchain will become immutable.
In this article, we move on discussing how cryptography works and what role it plays in a blockchain system. We also go over differences between public and private keys of cryptography.
Cryptography is the study of secure communication techniques that prevent third parties or the public from reading private messages and allow only the intended recipient of a message to view its contents. It is the cornerstone of information security, which serves as the basis for delivering secure business applications and services. Modern cryptography concerns itself with the following five objectives of information security:
- Confidentiality: This is the concept of preventing sensitive data from being accessible by any unauthorized entities.
- Integrity: This means protecting sensitive data from unauthorized changes during transit from one party to another party.
- Authentication: This is the process of ensuring that user identity is truly what the user claims it to be, whether the user is human or a system.
- Authorization: This is the concept of determining what actions an authenticated user is allowed to perform.
- Non-repudiation: When a user performs an action on data, the action must be bound with the user so that it can’t deny performing such actions.
Cryptography deals with the design of algorithms for encryption and decryption, which are intended to ensure the secrecy and the authenticity of the messages or transactions. Let’s start with some key elements in modern cryptography:
- Encryption: This is the process of converting plain text or data into an unintelligent form, typically using a mathematical algorithm.
- Decryption: This is the process of reversing encryption—converting an encrypted message back into its original text and data.
- Hash: This is the process of converting any data block (arbitrary size or message) into a fixed-length hash code. A cryptographic hash function is a deterministic mathematical function performing such a conversion using cryptography, and it always maps to the same result for a given data block.
Cryptography is a key cornerstone of blockchain technology, along with the consensus mechanism and decentralization. It is used in many different forms, including, for example, wallets (for proof of cryptocurrency ownership), transactions (for PoW consensus), and P2P communication. In this article, we will go over key blockchain-related cryptography topics, including public-key cryptography, digital signatures, cryptographic hashing, and Merkle trees.
Public key cryptography
Public-key cryptography is a form of cryptographic function in which encryption and decryption are performed using two different keys—one public and one private key. They are generated in pairs. It is also called asymmetric cryptography. The public key can be shared with the public, but the private key is meant to be a secret code only known by its owner.
The keys are used in tandem too. Either of the two keys can be used in encryption, with the other one used for decryption. It is computationally improbable to determine the private key given only knowledge of the cryptographic algorithm and the public key.
Public key cryptography is most used in three ways, to:
- Secure the message transmission between two parties and ensure the confidentiality of messages or data.
- Authenticate the sender and ensure the message is indeed sent from the sender.
- Combine with the cryptographic hashing function and provide a digital signature on a document before sending it to the receiver.
We will go over the first two here and discuss digital signatures in the following article:
- Public key cryptography for confidentiality: In this case, as depicted in the following diagram, the digital signature is used to encipher messages between two parties during transmission. The sender (Alice) uses the receiver’s public key to encrypt a message, and the receiver (Bob), who holds their own private key in secrecy, can decrypt the messages using their private key:
- Public key cryptography for authentication: In this case, as shown in the following diagram, the signature is used to authenticate the sender’s message. The sender uses its own private key to encrypt a message before sending it to the intended parties. The receiver can use the sender’s public key to confirm the message’s authenticity and decrypt it. The combination of this approach with the message’s cryptographic hashing function provides a digital signature, which we will discuss in the next article:
Public key cryptography is an essential technology underpinning wallets and transactions in the blockchain.
In the next article (What Is a Cryptographic Hash Function), we continue our discussion on cryptography by discussing how its hash function works.
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.
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
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: