Homework Task-2

(1) Write the definition of blockchain. And how our data on Blockchain is protected from hackers. ? And write details about Data, Hash and Previous Hash tag and explain through screenshot.

OR

(2) Define decentralization. Describe the advantages and disadvantages of a decentralized system. In what areas of life can a decentralized blockchain be helpful? (write in own words)

OR

(3) What is a block explorer? And what is its purpose and use? Search for different cryptocurrency block explorers and list them below. At least five different crypyo currencies. Also explore the transaction of a crypto coin on block explorer and explain with the help of screenshot.

BLOCKCHAIN

INTRODUCTION

Its the year 2021 and the world have come along way with the help of technological advancements. In a world of computers, financial transactions have come to see a new light with the introduction of a block chain, the back bone of a decentralized crypto currency.

Bitcoin paved the way for every crypto competitor in the year 2009 and since then, every crypto currency following after has used the same principle of block chain network.

What is a block chain?

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To explain it in a simple manner, we’ll have to look at the words “BLOCK” and “CHAIN” . If you can picture it in your mind, i would love you to think of individual boxes all filled with items..... Now think of all those boxes laid down in any format, connected together with a rope or per-say a chain. With this descriptive example we can say that a blockchain is basically blocks filled with information connected with other blocks through a chained network.

Since a block is linked together with other blocks including its previous blocks through a chain, all the data in the block is now verified and almost impossible to change

So a block chain is a digital ledger containing data of transactions which is duplicated and distributed across a whole network of computer systems on a blockchain.

How the block chain is protected from hackers

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Every block in a block chain acts as a ledger containing various transactions on the network and in a situation whereby a block gets filled up, the system creates a new block which is joined to gether with the previous one to continue the chain.

Every information in each block on a blockchain is verified by nodes all over the world.
Due to its decentralized nature it is distributed over multiple computers around the world and there is literally no way to trace the head because there isn’t any.

Like earlier explained, every block contains data of transactions so, whenever a new transaction occurs on a blockchain the data of the transaction is distributed across every participants ledger. In this decentralized database every transaction is recorded with a cryptographic signature known as HASH.

Due to the “hash” even if the database were to be bridged and the hash slightly change it will notify the system and the block will be removed from the chain as the system sees it as foreign and this then refutes intruders access.

Hackers would have to change every block on every distributed system to be able to hack into a blockchain which is impossible as there are millions of those. As a crypto keeps growing, more blocks are added and as more blocks are added into the chain, the more secure it is such examples can be seen in the bitcoin and etherum blockchain.

Components of a block chain

We’ve been talking about blockchain and from the lessons and this assignment you can pinpoint some keywords that has been said over again and again. These are things that make up or are part of the blockchain , the data, the hash and also the previous block hash code which ill be explaining pretty soon.

• DATA

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_{how transactions details are saved on a block<\sub>}

A data can be defined as units of information all gathered together. So a data is basically gathered information and in this case we are focusing on the information within every block on a block chain.

As explained earlier every block on a blockchain is just an archive of information containing records of transactions. This data gives us all the information we need and is only accessible to the sender snd reciever and cannot be changed. In cryptocurrency a data in a block gives us information such as the transactions of crypto from the sender to the receiver, when the crypto was sent, and how much crypto was sent.

All these financial transactions are the data saved within the block and cannot be changed or re-edited as they are serially marked with a Hash

• HASH

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_{the example above is a very descriptive of how a hash and a previous hash works}

A hash is a function which converts inputed arbitrary length into an encrypted output of fixed length. It means a hash is basically an encrypted demand which would help in solving blockchain computations.

Let me break it down, a blockchain uses cryptographic codes to encrypt a block and each codes are unique, meaning every hash on every block are different and authentic.

No block can be accessed and no information can be re-written or changed without this hashcode.
For example if the hash code of a block is 178F this will be used to identify the particular block in the midst of all other blocks on the block chain. It doesn’t only serve as security for the data but also to catalogue the information.

• Previous block hash code

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Just like how I explained earlier. When a blockchain is filled up with data, the system creates a new block to carry more information.
Originally the previous block has been encrypted with a cryptographic signature known as HASH. So what does the database do?

When a new block its created, the hash code of the previous block is also transferred to the new block so that this way, the hash code is existent in both the new block and the previous block.

Information becomes easily accessible this way because the new block and previous ones become connected together just like a chain with its own unique code. This makes the network decentralized and impossible to hack.

IN CONCLUSION

The blockchain has been very beneficial towards the growth of modern financial transactions, specifically cryptocurrencies. It is the back bone towards the decentralized nature of every cryptocurrency, it protects every users data , transactions and is impossible to hack. Truly its a very impressive technology. I’m happy for this lesson and hope to learn more as time goes on

Cc:
@yousafharoonkhan