Beginner’s Guide to Blockchain Technology

Learning about blockchain technology can be overwhelming. A blockchain is a culmination of several technologies and networking processes that happen like clockwork and networked worldwide through the internet. Don’t worry, we’ll break that down and simplify the key parts.

This article is a beginner’s guide to understanding blockchain technology. If you are keen on learning about Web3, this is the first educational piece you should refer to. This article will help you build the foundation for blockchain technology with relatable concepts, so let’s begin.

Introduction: The Medici and Birth of Modern Bookkeeping

During the Renaissance, a powerful family in Florence, Italy, rose to prominence through their patronage of the arts and a revolutionary approach to finance. The Medici family, known for their banking prowess, introduced something that would change the world of commerce forever: the double-entry bookkeeping system. This system, which meticulously recorded debits and credits, ensured their financial dealings were transparent and accountable, reducing errors and fraud. It was a game-changer, providing newfound trust in transactions.

The Medici’s innovation laid the groundwork for modern financial systems, establishing the importance of a reliable ledger for recording transactions. But what if the Medici had access to a ledger that was not just reliable but incorruptible, one that could be viewed by any person involved in the transaction(or anyone, period) and yet secure from tampering? What if this ledger didn’t just exist in one place but was distributed across a vast network of independent record-keepers?

Fast forward to the 21st century, and this is no longer a hypothetical scenario. The Medici’s ledger has evolved into what we now call blockchain technology. Blockchain takes the principles of the double-entry ledger to a whole new level, using advanced cryptography and decentralization. It’s a system where transactions are not just recorded but also verified by a vast network of computers, creating a transparent, immutable record that’s virtually impervious to fraud. This is the essence of blockchain, a technology poised to revolutionize how we think about and handle digital transactions, much like the Medici family did for banking during the Renaissance.

From Double-Entry Bookkeeping to Blockchain Technology

The Medici family’s double-entry bookkeeping system was one of the first evolutionary milestones in finance. It was the first idea that laid down a systemic approach to tracking the ownership and transfer of assets. The Medici bookkeeping systems were combined with various technologies and refined over the years with several practical and conceptual innovations that led to the birth of blockchain technology. Here’s a timeline of this evolution:

  • Double-Entry Bookkeeping (14th-15th Century): The Medici family, among others in Renaissance Italy, adopted the double-entry bookkeeping system, which records each transaction in two accounts: debits in one and credits in another. This system provided a clear, organized method to track the money flow and helped reduce errors and fraud.
  • The Advent of Computers (20th Century): With the invention of computers, accounting systems were digitized, allowing for faster processing, storage, and retrieval of financial transactions. This was the first major step in moving away from physical ledgers to digital ones.
  • Cryptography (1970s-1980s): The development of asymmetric cryptography, or public-key cryptography, allowed for secure communication over insecure channels and gave rise to digital signatures. This meant that transactions could be securely verified without needing physical presence or trust in a central authority.
  • The Internet (1990s): The widespread adoption of the Internet transformed the way data was shared and communicated, setting the stage for global, instant, and interconnected systems of commerce and communication.
  • Cryptographic Hash Functions and Merkle Trees (Late 20th Century): These technologies provided the means to verify large sets of data efficiently and securely. Merkle trees, in particular, allowed for quick data verification within large datasets, which would become a critical component of blockchain technology.
  • Peer-to-Peer Networks (Late 20th Century): The development of P2P networks for file sharing, like Napster and BitTorrent, demonstrated that distributed systems could operate without centralized control, with each node in the network acting as both a client and a server.
  • Digital Currency Experiments (1990s-2000s): Various attempts at creating digital currencies, such as b-money and Bit Gold, introduced concepts of creating, distributing, and verifying digital money without a central issuing authority. These systems, however, did not solve the double-spending problem.

What is the Double Spending Problem?

The double-spending problem is a significant challenge with digital currencies. Unlike physical money, which is tangible and cannot be easily duplicated, anyone can copy digital tokens. In a digital currency system, if safeguards are not in place, the same digital token could be copied and used in multiple transactions, undermining the trust and integrity of the currency.

In traditional banking systems, central authorities (like a bank) mitigate this issue. They maintain a ledger of account balances and transactions. This central authority verifies each transaction to ensure that the same money isn’t spent more than once. For a decentralized currency like Bitcoin, where there is no central authority to verify transactions, solving the double-spending problem is more complex. The system needs a way to agree on the validity and order of transactions to ensure that each unit of the currency is only spent once.

Proof-of-Work/Consensus Algorithms (2000s)

The concept of proof-of-work, initially proposed to deter spam emails, was adapted to create a consensus mechanism that could secure a decentralized network and solve the double-spending problem by ensuring that each transaction is only counted once.

Bitcoin: The First Blockchain (2008)

Satoshi Nakamoto combined these innovations to create Bitcoin, which features a secure, decentralized ledger of transactions. This ledger, or blockchain, was maintained across multiple nodes in a network with no central authority. It was a breakthrough in recording, verifying, and trusting financial transactions.

The Bitcoin Network is a distributed ledger where all transactions are recorded chronologically and publicly. Transactions are grouped into blocks, and each block is linked to the previous one, creating a chain. Blockchain network participants (miners) solve complex mathematical puzzles to validate transactions and add new blocks to the chain. Once a block is added, altering it becomes computationally impractical, securing the ledger against double-spending.

With the Bitcoin network, a decentralized ledger could finally support irreversible transactions. Once a transaction is confirmed and added to the blockchain, it becomes irreversible. This immutability ensures that once a digital token is spent, it cannot be spent again, effectively solving the double-spending problem in a decentralized environment. If you want to learn more about Bitcoin, be sure to check out our in-depth Bitcoin 101 Guide.

What is a Blockchain?

Blockchain is a decentralizeddistributed ledger that records transactions across multiple computers(nodes) in a way that ensures securitytransparency, and immutability. It employs cryptographic hashing and consensus mechanisms, such as Proof of Work or Proof of Stake, to maintain data integrity and prevent unauthorized alterations. Each record, or ‘block,’ is linked to previous ones, forming a chain, thereby making the history of all transactions permanently visible and verifiable by all participants.

Let’s break down each highlighted keyword:

  1. Blockchain: A blockchain is a system of recording information in a way that makes it difficult or impossible to change, hack, or cheat the system. It is a digital ledger of transactions that is duplicated and distributed across the entire network of computer systems on the blockchain.
  2. Decentralized: In the context of blockchain, decentralization refers to the transfer of control and decision-making from a centralized entity (individual, organization, or group thereof) to a distributed network. This ensures that no single entity has complete control over the entire network.
  3. Distributed Ledger Technology (DLT): This is a digital system for recording the transaction of assets in which the transactions and their details are recorded in multiple places simultaneously. Unlike traditional databases, distributed ledgers have no central data store or administration functionality.
  4. Transactions: In blockchain, transactions are the actions carried out in a blockchain network, such as the transfer of value, information, or rights. These transactions are grouped and recorded in blocks.
  5. Nodes: A node refers to a computer connected to the blockchain network. Each node has a copy of the entire blockchain ledger and participates in the network’s propagation. Nodes are responsible for validating and relaying transactions, contributing to the consensus process, and maintaining the integrity and security of the blockchain. They ensure the decentralization of the network, as each node operates independently and has equal authority to verify and record transactions.
  6. Security: In the blockchain context, security refers to the various cryptographic techniques and blockchain architecture used to ensure that transactions are securely recorded on the blockchain and the network is resistant to hacking and fraud.
  7. Transparency: Transparency in blockchain technology means that every transaction is publicly recorded in the ledger and can be seen by all network participants, making everything in the blockchain traceable and auditable.
  8. Immutability: Immutability in the blockchain means that once a transaction has been recorded in the distributed ledger, it cannot be altered or deleted. This is a fundamental feature that ensures the integrity of the blockchain and the permanence of the data recorded.
  9. Cryptographic Hashing: This is a process by which a specific algorithm transforms input data of any size into a fixed-size string of characters, which is usually a sequence of numbers. This hash is unique to the specific data input, making it a secure way of representing transactions on the blockchain.
  10. Consensus Mechanisms: These protocols ensure all nodes are synchronized with each other and agree on the true state of the distributed ledger. Examples include Proof of Work (PoW) and Proof of Stake (PoS).
  11. Proof of Work (PoW): A consensus mechanism that requires a participant node to solve a difficult computational problem in order to add a new block to the blockchain. This mechanism is used to confirm transactions and produce new digital currencies.
  12. Proof of Stake (PoS): An alternative to Proof of Work, this consensus mechanism allows a person to validate block transactions based on the number of coins the participant holds. This means that the more coins owned by a miner, the more mining power they have.
  13. Data Integrity: In the blockchain, this refers to the accuracy and consistency of data over its lifecycle. It ensures that data is not altered or tampered with.
  14. Block: A block, in the context of blockchain, is a set of recorded transactions that are combined into a single, cryptographically secure unit.
  15. Chain: In blockchain, a chain refers to a series of blocks in a specific order. Each block contains a reference to the previous block, linking them together in a chronological and unbreakable chain.
  16. Verifiable: This indicates that the data recorded in the blockchain can be independently verified by any participant of the network, ensuring trust and accuracy in the recorded information.

Popular Proof of Work (PoW) blockchains include likes of Bitcoin, Monero, Litecoin and others, while examples of notable Proof of Stake (PoS) blockchains are Solana, NEAR, Avalanche, Ethereum and Cardano. We have an article explaining Proof of Work vs Proof of Stake in detail if you would like to learn more.

A Bitcoin Network Cycle

The Bitcoin network employs the Proof of Work (PoW) consensus mechanism to validate transactions and add new blocks to the blockchain. Here’s a detailed step-by-step rundown of the process:

  1. Transaction Initiation: Users initiate transactions by sending Bitcoin to another user’s wallet address. Each transaction contains the sender’s and receiver’s wallet addresses, the amount of Bitcoin being transferred, and a digital signature created by the sender’s private key.
  2. Transaction Broadcast: Once created, the transaction is broadcast to the Bitcoin network. Nodes in the network (any computer with the Bitcoin software and the entire copy of the blockchain) receive and verify the transaction. They check the digital signature and ensure the sender has sufficient balance.
  3. Transaction Pooling: Verified transactions are pooled together in the memory pool (mempool). The mempool is a sort of holding area for transactions awaiting inclusion in a block.
  4. Block Formation: Miners (special nodes) select transactions from the mempool to form a new block. Miners typically prioritize transactions with higher fees. Each block has a fixed capacity, so not all transactions in the mempool may be included in the next block.
  5. Proof of Work: To add a block to the blockchain, miners must solve a complex mathematical problem (PoW). This involves finding a hash (think of it as the solution to the mathematical problem that needs to be accurate up to certain decimal places) that is below a specific target value. The process is computationally intensive and requires significant processing power.
  6. Block Verification: Once a miner successfully solves the PoW problem, the new block is broadcast to the network. Other nodes in the network verify the solution and the validity of the transactions in the block (e.g., ensuring no double-spending).
  7. Adding the Block to the Blockchain: After verification, the new block is added to the existing blockchain. Each block contains a reference to the hash of the preceding block, creating a chain of blocks. This linkage ensures the security and immutability of the blockchain.
  8. Rewarding the Miner: The miner who successfully adds a block to the blockchain is rewarded with newly created Bitcoins (block reward) and transaction fees. This incentivizes miners to contribute their computational power to the network.
  9. Network Update: Once the block is added, the updated version of the blockchain is propagated throughout the network. Each node updates its copy of the blockchain, maintaining the network’s consistency and integrity.
  10. Continuation: The process repeats for the creation of every new block, approximately every 10 minutes. Miners continuously select new transactions from the mempool, and the cycle of solving the PoW, block verification, and addition to the blockchain continues.

This consensus process ensures that all transactions on the Bitcoin network are verified and recorded securely, maintaining the decentralized, transparent, and immutable nature of the blockchain.

From Bitcoin to Web3

Bitcoin is fundamentally a peer-to-peer (P2P) network. Its primary purpose is to facilitate BTC transactions between parties while maintaining decentralization and permissionlessness. As the Bitcoin blockchain is designed for basic financial transactions, it doesn’t inherently support a system of complex programmable logic, or smart contracts.

A programmable logic would let users create transactions which would fulfil only when certain predetermined conditions are met, allowing them to program when a transaction gets executed. Bitcoin, therefore, doesn’t align directly with the concept of “Web3”. While it introduced the idea of decentralized transactions and inspired the development of blockchain technology, it doesn’t encompass the broader functionalities associated with Web3.

Inspiration for Smart Contracts and Web3

Web3, often referred to as the third generation of the internet, is a vision of a decentralized online ecosystem based on blockchain. Unlike the current internet (Web2), where data and content are largely controlled by centralized entities (like big tech companies), Web3 envisions a user-centric internet with decentralization, openness, and greater user utility and control.

Ethereum, created by Vitalik Buterin and others, extended the blockchain concept beyond Bitcoin’s scope. It introduced a platform where developers can build decentralized applications (DApps) and smart contracts, setting the stage for more complex interactions than just cryptocurrency transactions. The success of Ethereum showed that blockchain technology has applications far beyond financial transactions. It can be used for decentralized finance (DeFi), non-fungible tokens (NFTs), decentralized autonomous organizations (DAOs), and more, embodying the ethos of Web3.

Smart contracts have been pivotal in this evolution. They enable complex agreements and automated, trustless interactions in a decentralized environment, which are critical for the diverse functionalities envisioned in Web3.

Smart Contracts and Ethereum

A smart contract is a self-executing contract with the terms of the agreement between buyer and seller being directly written into lines of code. The code and the agreements contained therein exist across a distributed, decentralized blockchain network. The key characteristics and functionalities of smart contracts include:

  1. Automated Execution: Smart contracts automatically execute, control, or document relevant events and actions according to the terms of a contract. The code triggers the execution of the contract’s clauses when pre-defined conditions are met.
  2. Decentralization: Since they are deployed on a blockchain, smart contracts inherit the properties of the technology, including decentralization. This means no single party has control over the execution of the contract, reducing the risk of manipulation, fraud, or interference.
  3. Transparency and Immutability: Once a smart contract is created, it is transparent to all parties involved and cannot be changed (immutable). This transparency ensures that all parties understand the contract terms and cannot dispute the programmed actions once triggered.
  4. Security: Smart contracts use cryptographic security inherent in blockchain technology, making them secure and tamper-proof. This is crucial for trust in transactions and agreements.
  5. Efficiency and Speed: They can significantly reduce the time and effort involved in traditional contract processes, eliminating the need for intermediaries and reducing paperwork.
  6. Cost-Effective: Smart contracts remove the need for intermediaries, such as lawyers and banks, potentially reducing transaction costs.
  7. Accuracy: By automating processes and reducing manual intervention, smart contracts minimize the risk of errors that are common in traditional contract processing.

Smart contracts have a wide range of applications, including in finance (like automated loans or insurance contracts), supply chain management, digital identity, legal processes, and more. Computer scientist Nick Szabo first proposed the concept in the 1990s, but it was the development and implementation of blockchain platforms like Ethereum that brought smart contracts into practical use.

Smart contracts are considered revolutionary as, for the first time in human history, humans have the ability to enter into an agreement that does not require trust in the opposing party nor require any third-party intermediaries to facilitate the process. This results in contract fulfilment being far more efficient, cheaper, and eliminates the need to trust the parties involved as execution is autonomous. This reduces the risk of bad actors and fraudulent contractual agreements.


Ethereum is a decentralized, open-source blockchain system featuring smart contract functionality. Launched in 2015, it extends beyond Bitcoin’s primary function as a digital currency, providing a platform for building decentralized applications (DApps). Ethereum’s native cryptocurrency is Ether (ETH). It revolutionizes blockchain capabilities by offering a flexible environment for developing a wide range of applications, leveraging the security and decentralization of blockchain technology. Key innovations of Ethereum over Bitcoin are:

  1. Smart Contract-Powered EVM: Ethereum operates using the Ethereum Virtual Machine (EVM), a powerful, decentralized computational engine. The EVM interprets and executes smart contracts. The EVM environment enables developers to create a wide variety of decentralized applications (DApps) on Ethereum’s platform, from financial services and games to complex data management systems. Smart contracts on Ethereum are highly programmable, autonomous, and interact seamlessly with other contracts and DApps.
  2. Proof of Stake (PoS): Ethereum has transitioned to a Proof of Stake (PoS) consensus mechanism, known as Ethereum 2.0. Unlike Proof of Work (PoW), used in Bitcoin, PoS doesn’t require energy-intensive mining. Validators are chosen to create new blocks and validate transactions based on the amount of cryptocurrency they hold and are willing to “stake” as collateral. PoS offers increased energy efficiency, faster transaction processing, and enhanced scalability compared to PoW.
  3. Next-Gen Blockchain with Programmable Execution Layer: Ethereum represents a significant evolution from Bitcoin, often regarded as “Blockchain 2.0”. While Bitcoin’s blockchain mainly records financial transactions, Ethereum’s blockchain functions as a programmable, execution layer. This layer is where the smart contracts operate, offering a platform where developers can write and deploy code that executes automatically under specific conditions. This programmable layer, sitting atop the consensus mechanism, opens endless possibilities, transforming Ethereum into a foundational technology for decentralized applications and future blockchain innovations.

It is a crude comparison that isn’t exactly accurate and not everyone agrees, but to help wrap your head around the differences between Bitcoin and Ethereum, many users feel it is helpful to think of Bitcoin as digital gold while Ethereum is more akin to the internet. Bitcoin is a store of value and payment system, while Ethereum is looking to support the next evolution of the internet. Some also refer to Etehreum as “digital oil” as it essentially runs the Web3 world similar to how oil runs the physical machines and engines we use every day.

Parting Thoughts

As we conclude this beginner’s guide to blockchain technology, it’s important to recognize the monumental shift this innovation has brought into the digital world. From Medici’s double-entry bookkeeping to the sophisticated blockchain networks of today, we have witnessed a remarkable evolution in how transactions and data are managed. Blockchain technology, with its promise of decentralization, transparency, and security, is not just a technological advancement; it’s a paradigm shift in how we perceive trust and exchange value in the digital age.

For beginners stepping into the world of blockchain, remember that this journey is akin to exploring a new frontier. The concepts of cryptocurrencies, smart contracts, and decentralized applications are just the beginning. As blockchain technology continues to evolve, it will undoubtedly present new opportunities and challenges. The potential for blockchain to revolutionize industries is immense, but so is the need for responsible and informed engagement with this technology.

Your exploration of blockchain is not just about understanding a new technology; it’s about envisioning new ways in which we can build a more transparent, efficient, and equitable digital future.

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