Learn Blockchain: Bitcoin, Ethereum and Hyperledger Fabric

Explains why blockchain matters by examining business challenges—trust gaps, transparency shortfalls, middlemen, and manual processes—and shows how distributed ledgers enable trust without intermediaries and automate workflows.

Define centralized systems with a bank-ledger example and explain how trust and transparency issues, plus cross-border fees, drive the move toward decentralized approaches.

Assess the drawbacks of centralized systems in banking, including fraud, hacking, high transaction costs, and financial crises, and set up upcoming discussions on possible alternatives.

Explore how distributed and decentralized systems solve trust and transparency issues in centralized systems by using a peer-to-peer network of multiple servers with identical ledgers across all nodes.

Explore how distributed and decentralized systems enable a resilient peer-to-peer network with thousands of nodes, offering high availability, transparency, trust, and cost savings by removing middlemen.

Explore the blockchain concept and its features, and how information is stored in a ledger. Use a purchase example to show how transactions become a book of record keeping.

Explore centralized ledgers stored in ERP systems, with assets, orders, and customers, and contrast them with distributed and decentralized ledgers not owned by a single entity, improving availability and transparency.

Explore the basics of peer to peer networks, how direct computer to computer sharing works without a central authority, and why blockchain relies on this P2P foundation.

Blockchain is a peer-to-peer, distributed ledger that stores transactions in linked blocks, is append-only and immutable, and is updated only by consensus among parties, with public or private variants.

Explore the block structure, focusing on block header and transactions, with transaction counter varying and header elements like version, previous block hash, local root hash, timestamp, difficulty target, and nonce.

Explore blockchain features that enable a decentralized, high-availability network across global peers. Learn how transparency, trust, cryptographic security, and immutability empower direct, middleman-free interactions and broad enterprise use cases.

Initiate a blockchain transaction by sending from one address to another and attaching a transaction fee. Miners validate and broadcast the block across the network, driven by consensus and proof-of-stake.

Compare public blockchains with private and permissioned blockchains, showing how public networks offer transparency via visible transactions while identities are not exposed in plain text.

Explore how cryptography secures blockchain transactions, detailing blocks and block headers with hashes and references to the previous block, and contrasting public Bitcoin with private Hyperledger Fabric ledgers.

Learn how public and private keys secure information in cryptography, with the public key used to encrypt and the private key to decrypt, and private keys kept secret for signing.

Learn how symmetric cryptography uses the same key to encrypt and decrypt messages, and how asymmetric cryptography uses public and private keys for encryption, decryption, and signing for authenticity.

Learn how hash functions convert any input into a fixed-length value, yielding unique outputs, resisting input recovery, and securing and compressing blockchain data, with Bitcoin's SHA-256 example.

Explore how Merkle trees use hashes to securely verify and compress block transactions, culminating in the Merkle root hash that ensures data integrity and enables efficient queries.

Discover how blockchain consensus enables distributed nodes to agree on transactions, preventing double spending, with mining rewards motivating validation and secure storage of blocks.

Explore the two generals problem and its unsolved consensus challenges in distributed systems, as attackers disrupt messenger communication and synchronization.

Explore the general problem and its advanced version, where multiple generals must coordinate to defeat the enemy, despite traitors and information not being in sync.

Explore the concept of byzantine fault tolerance by examining a commander and lieutenants who must reach consensus despite traitors, using a two-thirds majority to decide attack or no attack.

Explore how proof of work drives consensus in blockchain by mining to solve mathematical puzzles, hashing transactions into blocks, and adjusting difficulty to validate new blocks.

Explain the drawbacks of proof of work, including energy consumption, mining pools and 51 percent attacks, and introduce the shift toward proof of stake.

Learn how proof of stake selects validators by stake, reducing issues seen in proof of work and enabling sanctions for block violations, while discussing maturity challenges and stake concentration.

Explore how bitcoin operates as a digital currency built on blockchain technology, tracing Satoshi Nakamoto's 2008 white paper to 2009 deployment, and its place in the broader blockchain ecosystem.

Learn how a bitcoin transaction moves funds from sender to recipient via wallets and addresses. Witness signing with a private key, network broadcast, validation, mining, and inclusion in the blockchain.

Discover how miners set bitcoin transaction fees based on transaction size and weight, and how those fees influence blockchain confirmation speed.

Bitcoin mining uses proof of work to validate transactions, solve a nonce puzzle for a hash with ten leading zeros, and reference the previous block.

Explore the Bitcoin networks, compare the mainnet production environment with the testnet, and learn how full and light nodes operate, including blockchain syncing and mining implications.

Explore how bitcoin wallets store public and private keys and generate bitcoin addresses, compare mobile, desktop software, chrome extension wallets, and hardware wallets, and highlight security risks.

Explore how the Bitcoin blockchain explorer shows blocks, hashes, and mining in a public blockchain. Learn to inspect transactions, coinbase rewards, and address activity using the explorer site.

Discover how Ethereum extends blockchain from Bitcoin to support smart contracts, decentralized applications, and enterprise solutions with its own cryptocurrency.

Discover how smart contracts automate asset actions on a blockchain, enabling ownership transfers, storing records like health data, and querying current owners of cars or land through deployed code.

Understand how smart contracts compile to bytecode and deploy on the Ethereum Virtual Machine, where they run securely on the blockchain, isolated from the host operating system.

Discover how gas powers blockchain operations by paying ether to deploy smart contracts and to call state-changing functions, while read queries incur little to no gas.

Explain the four Ethereum networks, with mainnet as the production network using proof of work and gas costs, and test networks to replicate mainnet scenarios.

Explore ethereum tools for smart contract development by writing in solidity, compiling with solc to bytecode, and deploying on test and main networks using web3, truffle, and IDEs.

discover the smart contract development lifecycle, from requirements gathering to design, development, testing, and deployment, with a focus on security and minimizing gas consumption.

Explore how the Ethereum explorer reveals blocks, transactions, gas usage, and smart contract interactions, and compare Ethereum’s fast block times to Bitcoin’s.