Steemit Crypto Academy Season 4 Beginners' course - Homework Task 4: Blockchain, Decentralization, Block explorer by @liasteem

liasteem (74)Beginner[4,5,9,10]in SteemitCryptoAcademy • 3 years ago

Assalamualaikum Prof. @yousafharoonkhan
And all Crypto friends wherever you are.
How are you all steemian friends?
Hope you all are always healthy and happy.

First I would like to welcome Prof. I am very happy to meet again with Prof. In this Crypto Academy Season 4. May you always be healthy and live long.

Thanks to Crypto Academy Season 4 for giving me and others the opportunity to participate and learn about cryptocurrencies. This is my first assignment as a beginner at Crypto Academy, I hope I can finish it well and if there is an error, please correct it from Prof.

(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.

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Source

Well I will answer the first of three questions about Task 4:Blockchain, Decentralization, Block explorer with the above questions.

Definition of Blockchain

Blockchain is an advanced and guaranteed technology and technology that has a high level of security and has a ledger where the ledger stores all digital data that is carried out and distributed in a decentralized manner (all can view and read data) to all nodes online, which can be accessed in smartphones, and laptops, where these storage systems contain records linked via cryptography.

Blockchain technology is very secure and transparent due to its decentralized nature. We can see the history of a transaction that occurred in this Blockchain. And because it has a high level of security, it is impossible for hackers to commit fraud and fraud because blockchain is also transparent so it minimizes hackers, because blockchain has several important parts in it, such as Data, Hash and Previous Hash tags.

And this blockchain technology can be accessed by anyone, anywhere via online without having to ask anyone for approval from a third party. For example in the Bank, where we have to take a queue number and queue, so we spend a lot of time, and also the bank will usually ask for some papers and documents, and if it is incomplete they will not authorize our transaction, this will consume a lot of energy, and to a single transaction will take energy, place and time, but by using this blockchain technology, all of these problems will be solved.

Blockchain works as an online distributed system and is verified by thousands of nodes worldwide. Blockchain works as a single block and is interconnected with other blocks, which blocks act as registry folders. and these other blocks are connected later with other blocks in great detail, and it is impossible to change them, because if the block is changed, then all subsequent blocks have to be changed and it takes a very long time.

how our data on Blockchain is protected from hackers?

Blockchain is a decentralized digital ledger then distributed, updated, then synchronized to all computer networks that are interconnected and depend on only one server. This means that only the user can control the data, and if one server goes down, don't worry, the data from that user is still stored on another computer network.

Blockchain also has the ability to protect data with cryptographic hashes, this means that data that has been entered into the network cannot be changed or modified. However, if there are additional data or other changes, the blockchain will still record it and the previous data will still be available.

For example;
In the world of health, by using blockchain technology, the hospital can add patient medical data into a computer network, where the network is interconnected and related to each other. All data, information, all transactions, and all logins made by users will be recorded, stored, and then confirmed by the parties involved. If one day the hospital needs the patient data back, then the hospital can view, access, and retrieve the patient data and if you want to update it, the data updated by the hospital will be stored without deleting the previous patient data.

Due to some of the reasons above, this blockchain technology will be very safe from hacking attempts or data modification. If this happens, then all users will get a notification. This is also a blockchain highly utilized by large agencies. If the hacker also wants to change the data, then he has to change the blocks, which are blocks that are intertwined and connected. If the hacker wants to change the data in the third block, then the fourth and fifth blocks also change. This is almost impossible, because to change it takes a very long and complicated time.

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

We must visit Blockchain Demo untuk mendapatkan contoh screenshot dari data, hash, dan previous hash.

✓Data

In blockchain data, all information and data are stored in every block on the blockchain. If in the cryptocurrency world, data stores all information and transactions about where the money is sent, to whom the money is sent, where it comes from, and how much the money is. Because all the data information is available in blocks, and it is impossible to change and manipulate the data.
Take a look at the description that will explain the data below!
This is information stored in the blockchain.

✓Hash

Hash is very important in blockchain technology and have a very unique code that varies from block to block. The hash gives the identification number of each block. Every data that is entered into the blockchain, the hash will change, even if we change one letter, the hash will change entirely. I will explain everything below later.

✓Previous Hash

Hash contains the address of the previous block, when the data is filled in a block, a new block will be created to store a lot of information, when a new block is created, the hash code of the block before this block is inserted into the new block and before the new block. Previous hashes are linked to new blocks that make up the decentralized Blockchain. If the block is changed, it results in a changed hash and results in a changed previous hash and because the new block has a connection with the previous hash, the hash is invalid and has to start over. That's why forming a decentralized Blockchain.

This is how data, hash and previous hash are important elements in blockchain technology

Block. 1
Miss. 11316
Data.
Prev. 000000000000000000000000000000000000000000000000000000000000
Hashes. 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

Block. 2
Miss. 35230
Data.
Prev. 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf
Hashes. 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

In the blockchain information above, we can see that each block has a different nonce, data, hash and previous hash.

Then I'll fill the block with Crypto Academy Season 4 information, and see what happens!

Instantly all blocks are invalidated and lo and behold the previous hash has no value, and the hash of the first block changes to 32268aaeafa8f88f26eb89862591923864b5fc877b58925beb4a00ebc3d1c8a3

I will try to change the data in block 3 with the information Crypto Academy Season 4.

Block 2 didn't change, but the next block I changed the information, changed the previous Hash and invalid hash, as well as the nonce that didn't change (12937).
If before the data is changed, the previous hash in block 3 is 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19 and hash 0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf.

This means the hash of block 2 is 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19 (which has the same value as the previous hash in block 3). It is this fact that makes previous hashes and hashes interconnected that form a decentralized Blockchain.

Then I will immediately click "mine" to make it easier for me to find the actual hash so that the block becomes valid and nonce 29468.
Prev. 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19
Hash. 0000ab172bf98f4282ed7ccf783f110dd6f24321dc406656eba4b0895c104aa9

But look, even though the third block becomes valid, the previous block is still invalid even though it has a hash and a previous hash that are related to each other.

Block 4 (before)
Miss. 35990
Prev. 0000ab172bf98f4282ed7ccf783f110dd6f24321dc406656eba4b0895c104aa9
Hashes. d55f20e20cd8c1c99d8f2156a7f44b670a70272a46c43a6823053fcf129c75ad

Block.5 (before)
Miss. 56265
Prev. 00003595e7c1da82c5c20ad966437224194da707df67ae748abae2afdf11aee3
Hashes. d9edea78c0cd67c1265d017c2c6f298909575370dc800b9c578e058022a40666

Now I will click the "mine" button on block 4 and block 5. Look!

Block 4 (After)
Miss. 29160
Prev. 0000ab172bf98f4282ed7ccf783f110dd6f24321dc406656eba4b0895c104aa9
Hashes. 00003595e7c1da82c5c20ad966437224194da707df67ae748abae2afdf11aee3

Block. 5 (After)
Miss. 9473
Prev. 00003595e7c1da82c5c20ad966437224194da707df67ae748abae2afdf11aee3
Hashes. 0000804351f2e67b9a2959c83f8bd1785ef9d57563d46868a06606b4f6ac371d

Well, from some of the screenshots above, we can see, read, and learn that the previous Hash and the next previous hash are related and if one block is changed, then the next block becomes invalid. So that blockchain technology is very secure and decentralized.

Conclusion

Thank you for learning prof. about Blockchain, Decentralization, Block explorer. I am very happy and enjoy this learning. I hope Prof. can except my homework and happy with my homework. More and less I ask you to apologize me.
Salam. 🙏😇
Thanks you for you all attentions.

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