Crypto Academy Season 3 Beginners' course - Homework Post for Task 2 by @ghulamabbassss

5개월 전


Write the definition of blockchain


Staurt Haber and W. Scott Sternetta were the first to introduce blockchain technology in 1991. However, before the launch of bitcoin in 2009, no such real-world application existed.

A blockchain database is a unique sort of database that never sleeps. Its name is derived from the combination of two words. Block and Chain, for example. A block is a data or information storage unit. Because blocks have limited storage limits, when one is full, the system will build a new block to store data. It will keep going as long as new data keeps coming in. And, finally, all of these blocks with validated data are linked together in a logical and chronological order, forming a chain of blocks.There are involved in cryptocurrency in any manner, we may observe that it has taken off. That are are the blockchain comes into play. Furthermore, we cannot deny that the majority of blockchain use cases are observed in the cryptocurrency market for recording and storing monetary transactions. Furthermore, not only can it be used to store bitcoin transactions, but it can also be used to store other types of transactions. Various blockchain-based projects are currently pushing forward to apply the blockchain for the benefit of civilizations and the entire planet.

How our data on blockchain is protected from hackers?

I'd want to start by discussing how the blockchain works in terms of decentralisation. That is, it operates according to a protocol over which no single person or organisation has control, but over which all users collectively have control. There are dozens or even millions of machines in a blockchain network.Nodes are computers that are operated by separate people or groups of people in different geographical places. Each node contains a complete record of the data since the blockchain's inception. And each new block is appended to the preceding block in a linear and chronological order, so that the new block has its own hash as well as the prior block's hash. Furthermore, when a block is added to the blockchain, it is assigned a precise timestamp.



Consider the case of a hacker attempting to change data. Their single copy will no longer align with the copies of other nodes if the data is modified. At this point, all of the other nodes will cross-refer to each other, making it easy to identify the node with incorrect data. And,against all the other nodes that are identical, the single duplicate with different data stands out. It will be deemed invalid if there is no procrastination. If a node makes an error in its data under specific conditions, it will use all of the other nodes in the network as a reference point to fix itself. This is how no nodes in the network can change the data held within them.When a blockchain is deployed in a decentralised manner, changing data is impossible. Thousands of nodes from all over the world can view and verify it, and it is saved inside the blocks. Furthermore, when a block is added to the chain, it is given an accurate timestamp, making it even more secure.

The purpose of blockchain is to enable for the recording and distribution of data without the ability to change it. It can also be called a safe and secure online distributed system in this way.

Despite this, the contents of a block can still be changed if it is in the best interests of the majority of nodes. For this to happen, the majority of people in the decentralised network must agree on the changes and reach an agreement on them.

When someone would wonder, if this is the case, how can we safeguard our data from a hacker. As I previously stated, the majority plays a critical role in changing the data in the blockchain. To succeed with such a hack, they must simultaneously control and alter at least 51% of the copies in the blockchain, effectively taking control of the majority of the copies. Furthermore, such an act necessitates the redoing of all the blocks, which requires a significant amount of money and resources.

Write details about Data, Hash and Previous Hash tag and explain through screenshot.

In order to build the blockchain, three elements are involved with the verification of the information in each block.
These are the following:

  • Data
  • Hash Tag
  • Previous Hash Tag


All of the block is made up of data. Any type of information can be considered data. When it comes to a specific cryptocurrency like bitcoin, it basically holds information regarding monetary transactions such as the transfer of cryptocurrency from sender to receiver. It expressly states how many tokens were sent from who to whom, as well as the precise time.



In the case of Steemit (a social media blogging platform), the steem blockchain also keeps track of non-monetary transactions such as posts, edits, comments, responses, votes, and reblogs.All of these types of transactions are recorded and saved as confirmed data in blocks that cannot be changed.

Hash Tag:

One of the most significant features in a block is the hash tag. It is distinct because the system creates it differently in each block. A math function converts digital data into a string of numbers and letters to produce these.
Let me show you one of the transactions from my steemit account in steemscan, along with the matching hash code. Then a I click the hash code, a new page appears with all of the transaction's characteristics, including sender, receiver, transaction type, timestamp, and digital signature. On the top, we can see the hash code


Furthermore, the hash code is the only way to validate the information's legitimacy. It can also be used as a block's identification number. It would be more exact if it were compared to human fingerprints. Hash code are changes if that information is changed in any way. This assists us in detecting any malicious activity on the blockchain. This is a feature that makes the blockchain irreversible in a decentralised setting.

Previous Hash Tag:

The previous hash code is what links all of the blocks together. Each new block is created as a result of new data being added into the blockchain.



As I previously said, the system assigns a hash tag to each block. When a block is completely filled with data. In order to contain the incoming data in the block, a new block will be constructed. The hash code from the previous block is now entered into the new block. This new block also receives a new hash code. This is how the blockchain's blocks are connected in such a way that no one piece of information can be changed.

😍Thanks for your time😍



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Hi @ghulamabbassss, Thank you for taking interest in the 2nd Task of the Beginners Fixed Class. Your grades are as follows:

Assessment AspectsRating
Presentation/Use of Markdowns0.7 / 2
Follow Rules and Guideline1 / 2
Quality of Analysis1.2 / 2
Clarity of Language1 / 2
Originality1.1 / 2
Total5.2 / 10

My Review and Suggestions:

  • You didn't put the questions you took at the beginning of the article.

  • Don't make your discussion writing italic, use italics to show only a few important words.

  • Get in the habit of putting a watermark with your username on every screenshot.

  • Put your screenshot in the middle of the page to make it look more professional.


  • Improve your writing skills even more by studying "Markdown Style Guide".

Thank you!