Good Evening to great people, I wish you always be good. This time i want to try participate in the exercise (Mini Crypto Program Part 3 | "Understanding of Blockchain" which was held by kakak @liasteem. Previously I had completed 2 exercises in the mini crypto program and all got scores above 5. It was a capital for me to participate in mini crypto program this time.

Understanding Of Blockchain

1. What is a Blockchain?

Source
Blockchain is a series of large open records that are managed by a group of computers in which there is no activity. record keeping system is digitally linked via cryptocurrencies. The network in the blockchain has no absolute authority because it is like a record in a shared ledger, but remains secure and immutable. all the information contained in the blockchain is open all can access it.

blockchain system contains all the data, time, place and any type of transaction make by the user. This technology is transparent so that it can know who is making transactions. This technology be can accessed for anyone via
smartphone or PC without having to ask permission from others. This technology have save time.

The blockchain system consists of transactions and blocks containing cryptographic hash and previous hash to form a network. the information recorded by the blockchain is permanent and can't be change. Blockchain technology consists of its main components, namely "blocks" which mean groups and "chain". The information on the blockchain is divided into blocks and is interconnected with chain.

2. Blockchain Type

When there are 4 types of blockchain that can be used for transactions, Public Blockchain, Private Blockchain, Hybrid Blockchain, Conortium Bockchain. but according to task, I will just explain one type of blockchain. in order, I'm interested in explain the "Public Blockchain".

3. Public Bockchain

The first blockchain to be introduced was a public blockchain with Use Case Cryptocurrency. Public blockchains are design to be completely decentralized without any one individual or others controlling the transactions recorded on the blockchain and the order in which they are processed.

What are the advantages and disadvantages of public blockchain

• Advantage
  On this blockchain is an open source transaction so that anyone can access this blockchain without restrictions. it is because of this nature that this blockchain has more users when compared to other blockchains. blockchain also provides a way to protect applications from development by specifying certain things even application developers do not have the authority to change Public. meaning that the records of these blockchain transactions are completely safe. This type of blockchain is very suitable for crypto assets, voting and fundraising.

• Disadvantage
  Because this blockchain is widely used, transactions on the blockchain are slow. Transactions have privacy because they are public.

4. Visit the Blockchain Demo, and what did you learn from that page? (screenshot required)

When I clicked on the link suggested by @liasteem brother, then I was immediately directed to this page.

I immediately tried the SHA256 hash

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• it can be seen that the SHA256 data is still empty with the hash number listed as e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855. A valid hash always shows some leading zero. so it can be concluded that the empty data is not valid.

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then I try to fill in the blank data with the word "try" then I get a hash number of 1e262cd7d110812f5726055a6e672b92cde43648b76adff51a12441fbdf7e667. the number obtained indicates that the hash is invalid.

• then I click the "block" bar menu appears as shown below:

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Blocks : 1
Nonce : 72608
data; empty
hash : 0000f727854b50bb95c054b39c1fe5c92e5ebcfa4bcb5dc279f56aa96a365e5a

On the "block" view you can see that the hash is valid because it starts with 3 leading zeros.

• Next step, I click to the "blockchain" menubar

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the "blockcahain" displays 5 blocks, each of which has a different Nonce but "prev" and "hash" are related to each other.
all hash numbers here have three leading zeros.

• Then I moved to "distributed". On a distributed blockchain there are three Peers (Peer A, Peer B and Peer C). Each pear has three blocks so there are a total of 9 blocks in distributed Blockchain. or can be seen in the following image.

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• On display "Tokens"

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in the token display, just like "distributed" there are 3 Peers each displaying token information.

• The last "coin base" this is how it looks.

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5. The the advantages and disadvantages of using blockchain technology

Whose name is technology, there must be a tug of war or advantages and disadvantages, so what are they?

• Advantages of blockchain

1. Records are very accurate
2. Low data storage cost
3. Deploy the database to all users without the need for a centralized server
4. User privacy is maintained

• Disadvantages blockchain

1. Blockchain can only add data without the ability to reduce the amount of data.
2. It takes a long time to confirm by making an agreement with the blockchain parties.
3. Sometimes the blockchain network is misused by irresponsible parties such as illegal buying and selling transactions.
4. No transaction recovery available
5. There is no law from the government.
   this is one of the biggest obstacles we experience when we transact with cryptocurrencies.

6. Conclusion

• Blockchain is a series of large open records that are managed by a group of computers in which there is no activity. record keeping system is digitally linked via cryptocurrency.
• 4 types blockchain : Public Blockchain, Private Blockchain, Hybrid Blockchain, Conortium Bockchain.
• The first blockchain to be introduced was a public blockchain with Use Case Cryptocurrency.

That's what I can explain, I realize there are still many shortcomings and mistakes. please give me a correction.
i'll invite @muhanansir, @dekbet and @hoesaid.

cc:

1. @irawandedy
2. @heriadi
3. @liasteem

Best Regard

@longhendra