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Table of contents
What is Blockchain?
Why is Blockchain Important?
Fraud Protection
Less Time of Transaction
High Flexibility
History of Blockchain
How Does Blockchain Work?
Key elements of a blockchain
Types of Blockchain
Public Blockchain
Private Blockchains
Consortium Blockchain
Hybrid Blockchain
Need for Blockchain Technology
Blockchain Applications
Blockchain Security
Features of Blockchain
Uses of Blockchain
Advantages of Blockchain
Disadvantages of Blockchain
Limitations of Blockchain
Future of Blockchain
Frequently Asked Questions
What are the four types of blockchain?
What are the features of blockchain?
What exactly is a blockchain?
What is a blockchain engineer?
Last Updated: Mar 27, 2024

What Is Blockchain Technology?

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Blockchain is a decentralized, distributed ledger technology completely transforming the digital world. It was first introduced in 2009. It allows for creating and maintaining secure and transparent digital transaction records. It is a database distributed across a network of computers. Each block in the chain represents a verified transaction or data added to the chain.

What Is Blockchain Technology?

While blockchain is most commonly associated with cryptocurrency, it has many applications beyond financial transactions. It has healthcare, real estate, voting systems, and supply chain management applications.

The technology uses a consensus mechanism to ensure that all network nodes agree on the validity of each transaction. Nodes on the network compete to solve a mathematical puzzle through mining.

What is Blockchain?

Blockchain refers to a digital ledger across a network of computers. The basic unit of blockchain is a block representing a successful transaction. It is a decentralized system which means that there is no control center. The blocks store information about the records and transactions. Each block has its storage, and the same information is stored in all the blocks.

The data stored in the block is immutable. The information cannot be changed or erased once accepted in a block database. The transactions are only accepted in a block after a verification mechanism. Since blockchain is immutable, it is a perfect solution for industries demanding high-security mechanisms. Blockchain is widely adopted by organizations dealing with sensitive data and is more prone to security attacks. For better security, blockchain deals with multiple cryptographic mechanisms as well.

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Why is Blockchain Important?

Blockchain is essential for below mentioned reasons:


For all the online activities, security is the primary concern. Data is leaked, and information is breached all over the web today. During these times, blockchain provides high security safeguarding the data. Its decentralized nature plays a vital role in this.


All the information is transparent, i.e., visible to all the users from the beginning. It reduces discrepancies in the system because anyone can see everything on this decentralized network.

Fraud Protection

By dint of high transparency and security, blockchain helps identify any fraud in the system. Any fraud cannot be hidden, and thus, it secures businesses from fraud.

Less Time of Transaction

Blockchain offers seamless transactions without much delay like traditional technologies offer. Sending and receiving of financial data or documents takes very less time to complete.

High Flexibility

Due to its various applications, blockchain is highly flexible in terms of usage. From cryptocurrency, and product tracking, to voting systems, smart contracts, etc., blockchain covers it all.

History of Blockchain

The timeline of blockchain goes as follows:

  • Satoshi Nakamoto released the white paper "Bitcoin: A Peer-to-Peer Electronic Cash System" in 2008.
  • The Genesis Block, the first Bitcoin block, is mined in 2009.
  • Ethereum was introduced in 2014, allowing the development of decentralized applications (dApps) and smart contracts.
  • Finance and healthcare are among the industries that have embraced blockchain technology.
  • Concerns have been raised about the scalability of blockchains and the environmental impact of cryptocurrency mining.
  • Blockchain technology is still evolving and being investigated for new applications.

How Does Blockchain Work?

The basic blockchain work occurs in the following steps:

  • Transaction Initiation: A user creates a digital record, and it is handed over to the network of nodes. This digital network is generally a complex mathematical problem. It contains information regarding the source and receiver.
  • Verification: The node reads the digital information and examines it. Once it is validated that the transaction is legal, it is added to the blockchain. The nodes use complex algorithms to validate it. The first node that solves the problem adds it to its blockchain.
  • Block Creation: The node that wins the race creates a new block to add the validated transaction to its ledger. A new block stores hashed data, the current address, and the previous block.
  • Consensus: Other nodes add a block to their ledger once a block is added. This is done after validating the transaction through multiple consensus mechanisms.
  • Block addition: Once all the nodes have accepted the transaction, we mark the block addition as successful. The block is an integral part of the blockchain and follows all its properties.

Key elements of a blockchain


1. Block: A block is the basic unit of a blockchain. It stores a number of transactions. Each block contains a timestamp, a reference to the previous block (except for the first block, also known as the genesis block), and the transaction data.

2. Transactions: Transactions are the actions carried out in the blockchain network. For instance, in a cryptocurrency blockchain like Bitcoin, a transaction could be a transfer of Bitcoins from one user to another.

3. Chain: The chain links all the blocks together. The blocks are linked in such a way that each block points to the previous block, creating a chain from the latest block to the very first block (the genesis block). This makes the blockchain immutable, as altering a single block would require changing every subsequent block.

4. Nodes: Nodes are the individual computers (also referred to as participants or peers) that participate in the blockchain network. There are different types of nodes, including but not limited to, full nodes that validate and relay transactions, and miner nodes that add new blocks to the blockchain.

5. Consensus Mechanism: This is a set of rules and procedures that all nodes in the blockchain network follow to validate new transactions and add them to the blockchain. Popular mechanisms include Proof of Work (PoW) and Proof of Stake (PoS).

6. Cryptography: Cryptography ensures secure and safe transactions on a blockchain. It's used to create digital signatures and hashes, which are essential to the functioning of a blockchain.

  • Digital Signatures: Digital signatures are used to confirm the authenticity of the digital documents or messages. In the context of blockchain, they are used to confirm that a transaction originated from a particular sender.
  • Hash Function: A hash function is a cryptographic function that takes an input and returns a fixed size string of bytes. In the blockchain, each block has a unique hash. Any change in the block content will cause the block's hash to change, which would disrupt the entire chain.

7. Decentralization: Unlike traditional databases that are managed by a single entity, a blockchain is shared among a network of computers (nodes). This means no single entity has control over the entire blockchain, and each entity in the network has the ability to validate and authenticate transactions.

8. Immutability: Once data has been written to a blockchain, it is extremely difficult to change. This is because each block contains its own hash, along with the hash of the block before it, as well as the timestamp. Any change to the transaction data inside the block changes its hash. It would also make all following blocks invalid.

9. Smart Contracts: Smart contracts are self-executing contracts with the terms of the agreement directly written into code. They automatically execute transactions when predetermined conditions are met. These are a key element in many blockchain networks, especially Ethereum.

All these elements work together to create a secure, decentralized, and transparent method of recording and verifying transactions. This technology has found applications in many areas beyond just cryptocurrencies, including supply chain management, healthcare, finance, and more.

Types of Blockchain

Blockchain can be broadly classified into four categories.

Public Blockchain

This blockchain is open to anyone who wants to join the network and participate in the validation process. The public blockchain is transparent and anonymous, meaning no central authority controls the network. Bitcoin and Ethereum are two well-known public blockchains.

Private Blockchains

These are those in which only authorized participants can join the network and validate transactions. Businesses and organizations that require privacy and confidentiality typically use private blockchains. Private blockchains include Hyperledger and Corda.

Consortium Blockchain

It is a hybrid of public and private blockchains in which organizations form a network to share data and validate transactions. They are most commonly used in industries where multiple organizations must collaborate. Consortium blockchains include R3 Corda and Hyperledger Fabric.

Hybrid Blockchain

Sometimes, the organization's demands require the best features of both public and private blockchains. In such a case, hybrid blockchain comes into play.

Need for Blockchain Technology

Some basic reasons for the need for blockchain are:

  • Decentralization: The existing systems today often have a command unit that controls the functionality of the entire network. In other words, they are centralized. Hence if the command center fails, the entire network ceases to operate.On the other hand, blockchain is centralized. It means there is no control center, and decisions are taken through consensus mechanisms.
  • Transparency: A lack of transparency can breed mistrust and fraud in various industries, including finance and voting systems. Blockchain is transparent because all transactions are visible and publicly accessible. This increases trust and accountability while also ensuring data accuracy and reliability.
  • Security: In traditional systems, data theft is a major concern. Blockchain technology provides high security by encrypting transactions and data with complex cryptographic algorithms. 
  • Immutability: Traditional systems are vulnerable to data tampering, jeopardizing data accuracy and authenticity. Once added to a blockchain, data cannot be changed or deleted, resulting in an immutable record of all transactions. This feature ensures data integrity.

Blockchain Applications

The application industries of blockchain include:

  • Cryptocurrencies,
  • Identity verification,
  • Voting,
  • Banking and Finance,
  • Healthcare data management,
  • Real estate transactions,
  • Peer-to-peer energy trading,
  • Decentralized gaming platforms,
  • Intellectual property management

Blockchain Security

The main factors involved in blockchain security are:

  • Consensus Mechanisms: The consensus mechanism is a critical component of blockchain security. It determines how transactions are validated and added to the blockchain. There are various consensus mechanisms available, such as Proof of Work (PoW), Proof of Stake (PoS), and Delegated Proof of Stake (DPoS).
  • Private Keys: Private keys are used to sign transactions and provide cryptographic proof of ownership. If a private key is compromised or lost, it can lead to unauthorized access.
  • Smart Contract Security: Smart contracts are self-executing code that runs on a blockchain network. They are used to automate complex transactions and operations. 
  • Network Security: Blockchain networks can be vulnerable to 51% attacks, distributed denial-of-service (DDoS) attacks, and Sybil attacks. Therefore, it is essential to ensure the network is properly secured.
  • Governance and Regulations: A blockchain network's governance structure and regulatory framework play an important role in its security. 

Features of Blockchain

The basic features of blockchain are:

  • Decentralized: No central authority.
  • Immutable: Once data is recorded on the blockchain, it cannot be changed or deleted.
  • Distributed: Copies of the blockchain ledger are held on multiple nodes across a network.
  • Consensus-driven: Changes to the blockchain are only made through a consensus mechanism agreed upon by all participants.
  • Secure: Cryptography is used to secure transactions and prevent unauthorized access.
  • Transparent: All transactions on the blockchain are visible to all participants, providing transparency and accountability.
  • Programmable: Smart contracts can be written and executed on the blockchain, allowing for automated and trustless execution of agreements and transactions.
  • Interoperable: APIs and interfaces can integrate Blockchain technology with other systems and platforms.
  • Efficient: Transactions on the blockchain can be processed quickly.

Uses of Blockchain

  • Secure digital transactions: Facilitates secure digital transactions without the need for intermediaries such as banks or the government.
  • Cryptocurrencies: The most popular use of blockchain technology is cryptocurrencies such as Bitcoin, Ethereum, and Litecoin.
  • Product tracking: Blockchain can be used to track and verify the origin of products as they move through the supply chain.
  • Verification: Blockchain can be used to create decentralized identity verification systems.
  • Smart contracts: Blockchain technology can create and execute self-executing contracts. The agreement terms between buyer and seller are directly written into code.
  • Healthcare data management: Blockchain creates secure and transparent systems for managing healthcare data.
  • Voting systems: Blockchain creates secure and transparent voting systems, reducing election fraud.

Advantages of Blockchain

  • Transparency: It provides a system where all participants can see the transactions.
  • Security: It uses advanced cryptography to secure transactions, making hacking or manipulating the system difficult.
  • Immunity to tampering: Once data is recorded on the blockchain, it cannot be altered or deleted.
  • Efficiency: The system is highly efficient with minimal system costs.
  • Traceability: Enables complete tracking of products from source to consumer.
  • Reduced Costs: It is cost-effective because no third party is involved.
  • Accessibility: It is a global technology that only requires a stable internet connection.

Disadvantages of Blockchain

The following are the disadvantages of blockchain technology:

  • Performance: Since many operations are associated with blockchain, its performance reduces significantly. For each transaction, all the blocks store its information. This means that number of operations increases exponentially.
  • Space Consumption: Since each node stores complete transaction details, the network requires huge space.
  • Implementation Cost: Although blockchain saves third-party costs during smart contracts, it is quite expensive to construct the basic foundations of blockchain.
  • Data Modification: Data in the blockchain is immutable. Hence apart from a verified source, data cannot be deleted or manipulated. At times, legal data modification becomes a tedious task.

Limitations of Blockchain

Some limitations of blockchain are as follows:

  • Scalable
  • Governance
  • Immutable
  • Difficult to operate
  • Space requirements

Future of Blockchain

Some expected evolutions in blockchain may be:

  • Collaboration with other technologies: Blockchain is expected to function smoothly with other popular technologies such as ML, IOT, and AI. In the upcoming years, blockchain is expected to increase the efficiency of various other computer science domains.
  • Better Consensus mechanisms: The existing consensus mechanism may be tedious and have performance issues due to many iterations. Efforts are made to develop better validation mechanisms to improve efficiency. Since, for each transaction, every node performs a validation process; it is necessary to develop a low-complexity consensus algorithm.
  • Easy modification access to the legit source: Data in a block remains immutable due to security issues. Hence it becomes extremely difficult to modify data when we desperately need to do so. In the upcoming years, it is expected to develop some mechanism that enables quick modification of the ledger while enhancing the same security capabilities.
  • Increased Adoption: This is the aspect of the future whose glimpses are visible currently. The expansion of blockchain in both public and private domains has occurred exponentially in recent years. Globally, there are less than five nations that have declared blockchain illegal. The Government of India has shown keen interest in adopting blockchain in government departments for smooth functioning. There are multiple MNCs where blockchain is already installed or in the installation process.
  • Expansion in IOT and Digital Advertising: Since blockchain is transparent and reliable, this technology can better deal with advertisement-related transactions. In the upcoming years, an immutable ledger will be installed in sensors and actuators, thus marking a collab between blockchain and IoT.

Frequently Asked Questions

What are the four types of blockchain?

The four types of blockchains are public, private, consortium, and hybrid.

What are the features of blockchain?

The most common features of blockchain are immutability, consensus-driven, decentralization, cryptography-enabled, distributed, transparency, and efficiency.

What exactly is a blockchain?

Blockchain is a decentralized and distributed database or a ledger among a network of computers. It provides the facility for the recording of transactions and tracking different assets across the web.

What is a blockchain engineer?

A Blockchain engineer is a professional who develops, designs, operates, analyzes, implements, and supports a distributed and decentralized blockchain network. A blockchain engineer can handle different models dealing with blockchain technology.


Hence, we conclude that blockchain is a decentralized, immutable ledger capable of collaborating with almost all aspects of computer sciences, including digital marketing and the Internet of Things. It is distributed in nature, which allows better transparency and security. We observe that blockchain is equipped with numerous advantages over traditional databases.

One of the most significant blockchain applications includes cryptocurrencies such as bitcoin and Ethereum. Blockchain efficiently maintains bitcoin transactions and supports bitcoin mining. This mining systematically takes place, regulating the number of bitcoins mined.

As the number of bitcoins mined to date increases, its value gradually decreases. Blockchain can potentially transform how we store and transfer data and value. However, it will require continued development and improvements to address its limitations.

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