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What is Blockchain? | Getting Started
course content

Course Content

Introduction to Blockchain

What is Blockchain?What is Blockchain?

As we have already mentioned, blockchain is a revolutionary technology that underpins cryptocurrencies like Bitcoin and has far-reaching potential across various industries. In fact, Bitcoin is not the only blockchain, there are countless other blockchains, however, the most important ones are based on Bitcoin model, so we'll focus on this model in our course.

Understanding Blockchain

First of all, it is important to define what a blockchain is.

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A blockchain is essentially a chain of blocks, where each block contains a collection of transactions or data. The data in these blocks can represent anything from financial transactions in the case of cryptocurrencies, to contracts, identity information, or other types of records.

You can also think of blockchain as a global distributed ledger. The data in a blockchain isn't saved in a central database or a file somewhere, but rather distributed across a network of various devices, each of which holds a copy of the entire ledger. Each device within such network is referred to as a node.

Let's take a look at the visualization of such network to make things clear:

Blockchain network

As you can see, there is indeed no central database, and the network itself is distributed among various devices. This decentralization ensures that no single entity has control over the entire network, enhancing security and resilience.

Not every distributed ledger is a blockchain since blockchain implements encryption with public and private keys, which we'll discuss later in the course, for security reasons.

Why Blockchain?

You may wonder what is so special about blockchain after all. Well, despite being decentralized, blockchain has the following key characteristics:

Immutability

Once data is recorded on a blockchain, it becomes nearly impossible to alter. Any attempt to change the information in a block would require altering all subsequent blocks, which is computationally impractical, which in turn makes blockchain secure.

Here is an example of a part of blockchain:

Each block has a unique identifier and some data, which is stored as 0s and 1s in computer memory.

In order to be valid, each block must refer to the preceding block.

In real blockchains like Bitcoin, there are actually thousands of such blocks with data. Besides, in Bitcoin, for example, a new block is created approximately every 10 minutes on average requiring a lot of computational power. Imagine how much time and computational power it would take to alter all of these blocks and verify the data in each of them.

Transparency

While the identity of participants can be pseudonymous, the transaction themselves or other data are visible to anyone with access to the network. This transparency helps build trust among participants and makes the system auditable.

Applications of Blockchain

While blockchain is most famously associated with cryptocurrencies, its potential applications extend far beyond. Let's take a look at some of them:

Field of Application Description
Smart Contracts Self-executing contracts with the terms of the agreement written into program code
Supply Chain Management Providing transparency and traceability in supply chains
Healthcare Securely managing patient records and sharing medical data
Voting Systems Creating tamper-proof and transparent voting mechanisms
Identity Verification Offering a secure and immutable way of managing digital identities

What is a blockchain?

Select the correct answer

Everything was clear?

Section 1. Chapter 2
course content

Course Content

Introduction to Blockchain

What is Blockchain?What is Blockchain?

As we have already mentioned, blockchain is a revolutionary technology that underpins cryptocurrencies like Bitcoin and has far-reaching potential across various industries. In fact, Bitcoin is not the only blockchain, there are countless other blockchains, however, the most important ones are based on Bitcoin model, so we'll focus on this model in our course.

Understanding Blockchain

First of all, it is important to define what a blockchain is.

oop

A blockchain is essentially a chain of blocks, where each block contains a collection of transactions or data. The data in these blocks can represent anything from financial transactions in the case of cryptocurrencies, to contracts, identity information, or other types of records.

You can also think of blockchain as a global distributed ledger. The data in a blockchain isn't saved in a central database or a file somewhere, but rather distributed across a network of various devices, each of which holds a copy of the entire ledger. Each device within such network is referred to as a node.

Let's take a look at the visualization of such network to make things clear:

Blockchain network

As you can see, there is indeed no central database, and the network itself is distributed among various devices. This decentralization ensures that no single entity has control over the entire network, enhancing security and resilience.

Not every distributed ledger is a blockchain since blockchain implements encryption with public and private keys, which we'll discuss later in the course, for security reasons.

Why Blockchain?

You may wonder what is so special about blockchain after all. Well, despite being decentralized, blockchain has the following key characteristics:

Immutability

Once data is recorded on a blockchain, it becomes nearly impossible to alter. Any attempt to change the information in a block would require altering all subsequent blocks, which is computationally impractical, which in turn makes blockchain secure.

Here is an example of a part of blockchain:

Each block has a unique identifier and some data, which is stored as 0s and 1s in computer memory.

In order to be valid, each block must refer to the preceding block.

In real blockchains like Bitcoin, there are actually thousands of such blocks with data. Besides, in Bitcoin, for example, a new block is created approximately every 10 minutes on average requiring a lot of computational power. Imagine how much time and computational power it would take to alter all of these blocks and verify the data in each of them.

Transparency

While the identity of participants can be pseudonymous, the transaction themselves or other data are visible to anyone with access to the network. This transparency helps build trust among participants and makes the system auditable.

Applications of Blockchain

While blockchain is most famously associated with cryptocurrencies, its potential applications extend far beyond. Let's take a look at some of them:

Field of Application Description
Smart Contracts Self-executing contracts with the terms of the agreement written into program code
Supply Chain Management Providing transparency and traceability in supply chains
Healthcare Securely managing patient records and sharing medical data
Voting Systems Creating tamper-proof and transparent voting mechanisms
Identity Verification Offering a secure and immutable way of managing digital identities

What is a blockchain?

Select the correct answer

Everything was clear?

Section 1. Chapter 2
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