What is blockchain?

14 June 2023

A brief history of appearance

Blockchain is a revolutionary technology that has changed the way data is stored and transmitted. The concept of blockchain was first introduced in 2008 by a man going by the alias Satoshi Nakamoto.

The first blockchain implementation was in the form of bitcoin, a decentralized digital currency that used a public base to record all transactions. The success of bitcoin sparked interest in blockchain technology, and other cryptocurrencies such as Litecoin and Ethereum were soon developed. 

As the potential of blockchain technology became more and more evident, various companies began to explore its use beyond just cryptocurrency. In 2015, the Linux Foundation Hyperledger, a project that aimed to develop enterprise-grade blockchain solutions, developed Hyperledger Fabric, one of the most popular blockchain technologies. As a result, Hyperledger Fabric, one of the most popular blockchain frameworks, was developed.

Today, blockchain is used in a wide variety of industries - healthcare, finance, supply chain management and more. It offers a number of advantages, such as increased security, transparency and efficiency.


Types of distributed registries (DLT)

Blockchain is based on distributed ledger technology (DLT). It can be divided into several different types. Each DLT has unique features and is suitable for different cases.

  • Public blockchains are open to anyone who wants to join and participate in the network. Transactions in public blockchains are transparent and can be tracked by anyone. Examples of public blockchains are Bitcoin and Ethereum.
  • Private blockchains are available only to a select group of individuals or organizations. They are often used where privacy and confidentiality are important. Private blockchains are still decentralized, but only authorized participants have access to the network. Examples of private blockchains are Hyperledger Fabric and Corda.
  • Hybrid blockchains are a combination of public and private blockchains. They can be used to securely connect multiple parties in a network while maintaining data privacy. Examples include Dragonchain and MultiChain.
public blockchains

Distributed Hash Tables (DHT)

DHT is a decentralized registry that provides data storage across a network of computers. DHT is an important part of blockchain technology because it enables a secure and transparent transaction base. On a blockchain network, each block contains a list of transactions that are validated and verified by nodes on the network. Once a block is validated, it is added to the database, creating an unchanging record of all transactions.

DHT provides stability, ensuring that the network remains secure and operational even if some nodes in the network fail or are compromised.

Another key advantage of using DHT in blockchain technology is the ability to search and retrieve data quickly and efficiently. This is very important for networks that contain billions of transactions. DHT allows nodes to quickly search for specific transactions, making it easier to verify and validate new transactions as they are added to the blockchain.

Oriented acyclic graphs/DAGs

DAG is a technology that processes transactions more efficiently than traditional blockchain technology. With DAG, each of the transactions validates the previous ones. This eliminates the need for miners, making the network more scalable and faster.

Unlike traditional blockchain networks, which require all nodes to validate each transaction, DAG allows transactions to be processed in parallel. DAG also eliminates the need for transaction fees, which is a significant advantage for microtransactions.

  • One of the most famous DAG-based cryptocurrencies is IOTA. It is designed for use in the Internet of Things (IoT). 
  • Another DAG-based cryptocurrency is Nano. Nano uses a blockchain grid structure that allows each account to have its own blockchain. This structure reduces the need for global consensus and leads to faster transactions and increased scalability.
blockchain technology


Hashgraph is a type of distributed ledger technology. Traditional networks are based on mining and confirmation through consensus algorithms, but Hashgraph uses a unique consensus algorithm called gossip about gossip, which allows it to process transactions more efficiently.

The technology is designed to handle up to hundreds of thousands of transactions per second, which far exceeds the scalability of traditional blockchain networks. This makes it an ideal platform for large-scale commercial applications such as supply chain management, finance, and data storage.

Hashgraph is also known for its fairness. Unlike traditional blockchain networks, where the order of transactions is determined by a consensus algorithm, Hashgraph orders transactions based on the timestamp of when they were received. This ensures fair processing and reduces the risk of network congestion.

One of the most well-known Hashgraph-based platforms is Hedera Hashgraph. Hedera is a public platform that aims to create a secure, fast and fair network for enterprises and developers. The platform provides a number of services, including smart contracts, file storage, and cryptocurrency.

What is blockchain used for?

Blockchain is an innovative technology that has found wide application in various fields due to its unique ability to provide reliability, transparency and security of data. Here are some of the main areas of application of blockchain:

  • Cryptocurrencies: Blockchain was first introduced as the technology behind Bitcoin and other cryptocurrencies. It provides a decentralized and reliable way to conduct financial transactions, eliminating intermediaries.
  • Digital Asset Management: Blockchain allows the creation of digital assets that can be used in various fields such as the gaming industry, art and real estate. These assets can be verified and transferred with minimal cost and risk.
  • Smart contracts: Blockchain allows you to create and execute smart contracts - software codes that automatically execute conditions when they are met. This can be useful in various fields, including finance, real estate, and even medicine.
  • Logistics and Supply: Blockchain can be used to track goods and their movement along supply chains. This helps prevent counterfeiting and ensure transparency in the delivery process.
  • Voting and Identity: Blockchain can be used to provide secure and authenticated voting, as well as improve the identification system.
  • Healthcare: In the medical field, blockchain can help manage medical records and ensure patient privacy.
  • Logistics and Transport: Blockchain can improve cargo tracking and logistics management, reducing costs and risks.

These are just a few examples of blockchain applications, and its potential continues to expand. Its main advantages are security, decentralization and reliability, which makes it a valuable tool in many industries and areas of life.

How blockchain works

Blockchain is a decentralized digital ledger that records transactions securely and transparently.

  • A block in a blockchain contains a group of transactions that have been verified and joined together. Each block also contains a unique code, called a hash, which identifies it and links it to the previous block in the chain.
  • Once a block is added to the chain, it cannot be changed without changing the hash of all subsequent blocks. This ensures the integrity of the data stored in the blockchain.
  • Blockchain is supported by a network of computers, each with a copy of the entire chain. Transactions are validated by multiple computers on the network, making it difficult for a single person or organization to manipulate the data.
technology blockchain

Benefits of blockchain technology

  • Decentralization. Blockchain technology operates in a decentralized network: No central authority or intermediary is needed to validate transactions. This makes blockchain more secure and resistant to fraud and manipulation.
  • Transparency. All transactions are recorded and stored in a transparent database at all times. This makes it easy to track, verify transactions and ensure that all participants have access to the same information.
  • Security. Blockchain networks use cryptographic algorithms to secure and validate transactions. The decentralized nature of blockchain technology makes it more resistant to cyberattacks. That is why it has found the greatest application in the financial sector.
  • Efficiency. Blockchain technology enables fast and secure peer-to-peer transactions. It eliminates intermediaries and shortens transaction times, making it an effective alternative to traditional financial systems.

Disadvantages of blockchain technology

  • Blockchain networks require a significant amount of energy to validate transactions.
  • The current architecture of blockchain technology limits its scalability. As more transactions are added to the network, the time it takes to validate transactions increases. This can lead to network congestion and slow transactions.
  • The decentralized nature of the technology makes it difficult to regulate. This can lead to a lack of oversight and accountability, making it an ideal platform for illegal activity.
  • Blockchain technology is relatively new and complex. This makes it difficult for users to understand and use.
  • The cost of implementing and maintaining a blockchain network can be quite high, making it difficult for small businesses and individuals to use.

Blockchain: a conclusion from Cryptology experts

In conclusion, blockchain technology has emerged as a revolutionary force that has transformed the way data is stored, transmitted, and verified. What began with the introduction of Bitcoin has now expanded to a wide range of industries, offering increased security, transparency, and efficiency in various processes.

The different types of distributed ledger technology, including public blockchains, private blockchains, hybrid blockchains, DHT, DAGs, and Hashgraph, provide diverse options to cater to different needs and use cases. These technologies have paved the way for secure and decentralized networks that enable trust and collaboration among participants.

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Frequently asked questions about blockchain

What is blockchain?

Blockchain is a decentralized and secure data storage system that uses a chain of blocks to record information. Each block contains a set of transactions and is stored on many computers (nodes) in the network.

How does blockchain work?

In a blockchain, each new transaction is verified by the nodes in the network and added to the block. The block is then chained to the previous block, creating an unbroken chain of data. This provides transparency and makes it impossible to alter past records.

What are the advantages of blockchain?

- Decentralization: No central governing bodies.
- Reliability: Records on the blockchain are protected by cryptography and sophisticated algorithms.
- Transparency: All transactions are visible to all participants in the network.
- Security: Transactions cannot be tampered with or altered.

What are the uses of blockchain?

- Cryptocurrencies, such as Bitcoin.
- Smart contracts: Automatic fulfillment of transaction terms.
- Supply chain management: Tracking goods and their origin.
- Voting: Ensuring secure elections.
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