Crypto Academy / Season 3 / Week 6 - Homework Post for @stream4u (Let's Open The Blockchain)

This week has entered the 6th week of season 3, I am very happy to be joining professor @stream4u class. This is a very interesting class, ok I will try to do the homework given this week

Background from canva

1.) What is Blockchain and What are the types of Blockchains / Explain in detail the types of Blockchain?

Blockchain

Blockchain is a system that stores digital data in a decentralized way so that after the data is input, the data cannot be changed or deleted, with this system blockchain is difficult to hack. because it contains the word chain in the word, it can be interpreted that a block is connected to the next block.

Blockchain also puts a lot of emphasis on system security, such as having a hash function. hash is a unique algorithm that has the same output length even though the given input has different lengths, the hash is a one-way function, so it is almost impossible to predict the input information from the output (hash).

Blockchain has the main components, namely:

• Blocks, blocks are encrypted digital data that is on the network and stored permanently.

• Nodes, nodes are computers that are connected and run the blockchain. this computer as a place to mine and validate data on the blockchain.

• Miners, Miners are people who run nodes and validate data and who mine on the blockchain.

Types of Blockchain

• Public Blockchain

Public Blockchain is a blockchain that can be accessed by any user provided that they have an internet connection. as the name suggests this blockchain gives freedom to anyone to participate in validating every transaction. Public blockchains usually carry out the validation process with a Proof of Work or Proof of Stake algorithm.

Public blockchains have several advantages such as, transparent, Blocks can be seen by everyone, in the field of security it is very difficult to hack because it has security such as hash functions that are very difficult to crack. Public blockchains also have some disadvantages, such as, because there are too many users, sometimes the network slows down because too many people access the blockchain.

• Private Blockchain

Private Blockchain is a blockchain that has limitations, this Blockchain must have permission to use it. Its use is usually used for certain companies and organizations, banks and others.

Private Blockchain has advantages such as high transaction speed because there are not many users in it. its security is better than public blockchain because it is not open to all parties. Private Blockchain also has several drawbacks such as not being transparent because it is not open to all parties, and access to private blockchains is also limited because not everyone can access it.

• Hybrid Blockchain

Hybrid Blockchain is a combination of the features of the public blockchain and the private blockchain. Selected members can determine whether transactions are made public or private. means network members can determine whether transactions should be published or not.

Hybrid Blockchain has several advantages such as high transaction speed, low maintenance costs and providing data security. Hybrid Blockchain also has drawbacks, such as the level of transparency is not very open because not all of them are published.

2.) What are the benefits of blockchain?

Well I will explain the advantages provided by blockchain technology

• Security

Blockchain security level is very good because any information that has been inputted can not be changed back and deleted this is very good in data storage and very difficult to hack.

• Transparency

The level of Blockchain data transparency is very good because there are several types of blockchain that can be accessed by every user without having to log in so that the data can be seen by every user

• Cost

The costs incurred in each transaction process are very low so that many transactions can be carried out at a certain time, this is very useful in saving the costs incurred for each transaction.

• Transaction Speed

In addition to the relatively low fees, the transaction speed offered by Blockchain technology is very good, so many users use this technology for various transactions.

• Trust

Because blockchain provides many advantages, it can be said that many users use this technology for their various purposes so that the reputation of the blockchain is very good in the eyes of users.

3.) Explain Blockchain Distributed ledger.

Blockchain Distributed Ledger

The distributed ledger is a very important part of the blockchain system. because the distributed ledger has a function in managing data and information in blocks. the data recorded in the block will be connected to each node so that any additional data input will be immediately synchronized. The distributed ledger is very transparent to every user.

any information that has been inputted cannot be changed again, as we all know that every inputted information will generate a hash and will be interconnected to any further information that is inputted with this system, all information that has been inputted cannot be changed and deleted.

Important Features of Blockchain Distributed Ledger

• The security is very good because it has a cryptographic function in the form of a unique algorithm called a hash

• High transparency, so it can be accessed by any user who wants to see the details of the transaction

• All user identities are anonymous so user privacy is very safe, this is all to minimize hacking

• All transaction data has been validated and cannot be changed. because it has a hash function that is interconnected with the next block.

4.) What Is Blockchain Double Spending and how Bitcoin handles this problem?

Blockchain Double Spending

Double spending is a system manipulation that occurs on the blockchain network, this can be called a form of fraud to profit from transactions made twice but the amount remains the same as the first transaction.

for example, when someone buys a cellphone for $500, after the transaction occurs, the money can no longer be used to make transactions, but in the blockchain system this can happen by manipulating the details of transactions that are duplicated and reset, this is all a crime as well as fraud in the blockchain system.

How does Bitcoin deal with this problem?

Miners otherwise known as validators, play an important role in validating the data for each transaction. The process is done by verifying the transaction using a hash algorithm. Once the transaction is validated and confirmed, the transaction will be added to the ledger on the blockchain network. Once a transaction is added to the distributed ledger, the data cannot be changed or deleted, with this process being able to handle the blockchain's double spending.

so every same transaction that is used to deceive sellers or manipulate transaction data, only one transaction is valid and all other transactions will be rejected. this can all be said to be able to overcome the problem of double spending that occurs on the blockchain.

5.) Practical + Theory, Visit Blockchain Demo and check section Blockchain, then explain in detail how Blocks Hashes Work in Blockchain, what will happen when any middle of the block gets changed, try to give screenshot for each possible details.

let's visit Blockchain Demo

in the picture above I try to input

Data: zacky07
Hash: f614a198361b7719da220b4159bcf408de900a12fd82b4248b00afa53c335fd5

keep in mind that every input given will produce a hash of the same length. although the length of the word character in the data provided, the hash length will remain the same. every slightest change will produce a different hash even though it only changes the capital letters as shown below

Data: Zacky07
Hash:
0b0baae1769a1aa9ef9cddab42051d841be191e618db96b213f7847006c80e7f

we can see the difference in the hash of the difference in capital letters with the same word.

Next let's visit the blockchain page.

From the picture above we can see that block 1 has:

prev: 000000000000000000000000000000000000000000000000000000000000

Hash: 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

From the data above, it can be concluded that block one is not referred to any block or is usually called the genesis block

Block 2 has:

Prev: 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

Hash: 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

From the data above we can conclude that the previous hash of block 2 is the hash of block 1 this proves that each block is related to the next block.

From the picture above we can see that block 3 has:

prev: 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

Hash: 0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf

From the data above we can conclude that the previous hash of block 3 is the hash of block 2 this proves that each block is related to the next block.

Block 4 has:

Prev: 0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf

Hash: 0000ae8bbc96cf89c68be6e10a865cc47c6c48a9ebec3c6cad729646cefaef83

From the data above we can conclude that the previous hash of block 4 is the hash of block 3 this proves that each block is related to the next block.

so we can see from the screenshot of block 1 to block 4 each block will be related to the next block

we can see from the picture above when I add the word "messi" to block 1 then all block one becomes invalid and affects other blocks this is marked hash does not start with zero. Likewise with the second block when I add the word barcelona we can see that the previous hash is the hash in block 1 even though it is not valid. This proves that each block is still related to each other even though it is not valid. how to make it valid?

how to make it valid by clicking "mine" then the block will be valid this is all related to the given nonce because when we click on the word "mine" let's see what happens

From the picture above, we can conclude that a valid block is marked with a hash starting with zero and we have been given a new nonce according to our input data. The hash is also related to the next block.

6.) What Is Race Attack in blockchain? OR What Is Finney Attack in blockchain? OR What Is Vector76 Attack in blockchain?

Race Attack in Blockchain

Race Attack is a type of double expenditure made by hackers by using the same crypto assets in various transactions. this is all done to deceive users into making transactions for personal gain. This process occurs when the buyer wants to send a certain amount of money to be given to more than one seller. so when the seller immediately trusts the transaction before the transaction is validated then he will be deceived by the transaction that has been manipulated by the seller or fraudster.

To avoid race attacks, patience is needed to wait for transaction validation by miners or validators. In validating a transaction which is a race attack, only one transaction that is taken first by the miner is considered valid, so other transactions will be considered invalid. so we have to be patient to wait for transaction validation from miners to avoid scams or race attacks.

7.)Limitations/disadvantages of Blockchain.

Blockchain has several limitations, namely:

• Cost

As we all know, for miners, the costs required to start mining are very large, such as buying expensive equipment that is used to make mining faster and more convenient, this certainly requires a large amount of capital.

• Scalability

because all are free to access and the number of nodes that are interconnected, it can have an impact on slowing down the network system. such as speed in transactions and data processing on the blockchain network.

• Eternity

although it has an advantage, it has a disadvantage because any important data that has been inputted cannot be changed again which will have an impact on the user's loss, therefore blockchain users must be more careful and observant before inputting.

• High Power Consumption

For a miner, in using a computer device that has high specifications, it must use very high power because it continues to be used every time, if it fails, it will suffer losses in the field of paying large electricity costs.

8.)Conclusion

Blockchain is one of the innovations that is very good for use in everyday life, with some of the advantages it provides, I believe it can make it easier for users to save time and money, even though having some drawbacks is a common thing.

The blockchain system also places great importance on security, such as a hash function in the form of a unique algorithm that it has and is interconnected with the next block so that it is difficult to hack, not only that. The blockchain system is also very transparent so that anyone can access it, if all of this can be realized in everyday life then definitely very helpful for users.