What is Blockchain?

Blockchain is a digital file that is used to store data and information. Like any other computer file, it is made of zeros and ones, and computers process it and show it in a form that humans can understand. But blockchains are different from normal files because they have three main features.

1) Distributed:

A normal file, like the one you are reading now, may be saved on only one computer and other people can access it through the internet. But in a blockchain, the full file is saved on many computers at the same time.

Because of this, no single person or organization can change the file alone. A change is only possible when many computers (that have the same copy of the blockchain) agree with each other.

2) Cryptography:

One of the most important innovations of blockchain is cryptography. The information inside a blockchain is encrypted in a special way. This means that to change the data—or in some types of blockchains, even to see the data - you need special private keys.

This system makes unauthorized access to the data almost impossible.

3) Transparency:

In many blockchains, the data is public, and anyone connected to the network can see the changes in the blockchain. In some cases, access is limited to specific people. For example, some organizations or companies use private blockchains for internal use only.

Blockchain Structure:

As the name shows, a blockchain is made of connected data blocks. Each block contains different information, such as:

• A link to the previous block: Each block is directly connected to the block before it.

• Time stamp: Each block has a time stamp that shows when the information was created or updated.

• Data: The stored data can be things like Bitcoin transactions or information about who owns products and services.

Uses of Blockchain:

The first blockchain was designed by a person named Satoshi Nakamoto in 2009 to create the digital currency Bitcoin. Bitcoin was the first big use of blockchain, but soon this technology was used in many other areas.

Some important uses of blockchain are:

• Government records: Blockchain can store public records like marriage certificates, company registration, and health records.

• Tracking products in supply chains: Big companies مثل Walmart and De Beers use blockchain to track products from producers to distributors.

• Finance and international payments: Blockchain can remove payment middlemen and reduce transaction costs.

Challenges and Risks of Blockchain:

Even with many advantages, blockchain still has some serious challenges. One of the biggest problems is high energy use. For example, the Bitcoin network uses so much energy that it is similar to the yearly energy use of Ireland.

Also, many projects look at blockchain with too much excitement and advertise it as a solution for every business problem. While blockchain has strong and useful applications, it is not always the best solution. Sometimes, building a blockchain system can be complex and expensive.

Blockchain and Problems in Distributed Systems:

One important problem in distributed systems is the Byzantine Generals Problem. This problem happens when many systems try to reach an agreement in uncertain conditions and with communication issues.

Blockchain was designed to solve this kind of problem. Different nodes in a blockchain network must agree on which information is correct, and then all copies of the blockchain update at the same time.

Centralized, Decentralized, and Distributed Systems:

Blockchain mainly works in a decentralized system. In decentralized systems, no single organization can make decisions alone, and everyone must agree.

This is different from distributed systems, where data is stored and processed in different places, but some organizations may still have more control over managing the system.