Hello Everyone!

This is Sami Zuberi , hope you all are well. I am exceptionally hope set aside a few minutes for perusing my homework post for @stream4u and valued it. Here i am going to impart my views on " Let's Open the Blockchain". So how about we begin.

Question no 1:

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

Blockchain :

Many people believe that blockchain, as the technology that powers Bitcoin, can do so much more. Despite popular belief, there isn't just one blockchain. Blockchain refers to a group of distributed ledger technologies that may be used to record and monitor anything of value, including financial transactions, medical information, and even property titles. Blockchain organizes data into groups called blocks, which are linked chronologically to form a continuous line. If you modify the information recorded in a block, you don't have to rewrite it; instead, the changes are saved in a new blockchain. Blockchain was created with the goal of being decentralized and spread over a large number of computers. This decentralizing of information reducing the ability for data tampering. It creates trust in the data. Blockchain is a technology that may be used in a variety of ways.

Source

Types of Blockchain.

There have been three different types of blockchain technology.

Public Blockchain.

Publicly accessible blockchain are simply termed as Public Blockchain, further these blockchains have no restrictions on the participant and the validator also the main advantage of this type of blockchain is the uncontrollability of the blockchain which means that nobody has a complete control over the network hence its ensure that the data is secure and helps in immutability of the records. Furthermore, all nodes linked to this public blockchain will have equal power, resulting in a completely distributed public blockchain.

Private Blockchain.

As the name implies, this blockchain needs participants to be invited before they may join. Only those who are a part of the blockchain ecosystem may see all of the transactions. These types of blockchains are centralized and much better controlled than public blockchains as the blockchain are more centralized here they can be governed and regulated by someone who can make sure that the governors are guiding participants also these blockchains can have a token or may not have one and can be manipulated based on the preference of the blockchain owner. Private blockchains often include a network administrator who can manage user permissions in the event that a specific user demands more authority on the fly. These are frequently utilized in private businesses.

Hybrid Blockchain.

Hybrid blockchain can be divided into two types, with some nodes being private and others being public. As a result, some nodes will be allowed to participate in transactions while others will be in charge of the consensus process, resulting in a hybrid blockchain that is a mix of private and public blockchain. The blockchain may reach all of the nodes here. The degree of information that may be obtained will be determined by the node that is accessing that data. In this blockchain, there are two sorts of users: one who has complete authority over the blockchain and determines the level of security for each user, and the rest who just access the blockchain to do their functions.

Question 2.

What are the benefits of blockchain?

Benefits of Blockchain.

• Blockchain is a distributed, secure, transparent, immutable, and accessible data structure that represents a ledger programmed to record and monitor anything of value.

• Blockchain has distributed structure and no central point of authority, This protect the system from the corrupted nodes .

• Blockchain is made up of digital blocks that store information about every transaction that has ever taken place on the network.

• When a portion of the data is tampered with, the system rejects it and the system stays safe. As a result, the data is immutable.

• Data cannot be altered, and each modification results in the creation of a new block.

• Blockchain is open to all parties, allowing them to share information and ensuring a seamless and quick flow of data.

• All blockchain transactions are processed much speedier than they were prior. Upon that network, transaction traceability is simple because all of the procedures involved in that process be stored and accessible to anybody who wants to see them.

Question 3.

Explain Blockchain Distributed ledger.

Blockchain Distributed Ledger.

Distributed Ledger Technology is a method of combining a number of blocks in a chain. The major goal is to get rid of the problem of a centralized database. Because it eliminates the need for an intermediary or centralized system, it can greatly speed up transactions. Distributed Ledger Technology is made up of a network of participants who each have equal power over the system. This makes it impossible to hack or control the system, and it also provides for a transparent network where all members can see what is going on. Before you can save data on the blockchain, it must first be authorized and confirmed by all of the participants. Once the information is accepted, the hash is used to create a unique identification. When a person joins the network, they automatically receive a full copy of the ledger, making them a member of the network. They also become a validator, who is in charge of verifying transactions. This type of validation adds to the security of the system because any changes to the chains must be approved by the network participants.

Question 4.

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

Blockchain Double Spending.

Double spending means spending the same money twice so every type of monetary system has policy in place to guard against this. We have both real money and debit or credit cards, so when you have physical money and go to a merchant, you show the cash and they give you the products. You can't take the same cash and spend it again because the vendor has it, the merchant has your money, and you have the goods you bought. You can't do the same thing with a debit or credit card because your balance is updated in real time, and the transaction is updated, and you can't spend your money twice. However, Bitcoin transactions are not instantaneous and cannot take place in real time right now. There is a concept of double spending, which means I may transfer money to person 1 with one Bitcoin and then to person 2 with the same Bitcoin before the transactions are validated. The Bitcoin network was created to prevent the duplicate spending.

Bitcoin Solve Double Spending Problem.

Bitcoin created a rule for handling a double spending problem named as the longest chain rule. It is one of the security feature. So how's the rule work? Let's consider a scenario that Person A holds 5 bitcoins in his wallet and he wants to buy a car, so for this purpose Person A visits two car dealerships and he found a perfect car from one dealer and also he found a perfect car for himself from a second dealer simultaneously. And both the dealerships demands 5 bitcoins as the price of car. Now there is a problem for Person A that he likes two cars from each of the dealership that has a price of 5 5 bitcoins and he only has 5 bitcoins. Either he thought to do double spending means spend his 5 bitcoins at the same time with both the dealerships. This is the problem of double spending. Now bitcoin solve these problem in a way that when Person A transact his money to both the dealership of car so the transaction first stuck in a uncertain pool and that is called un validated transactions. Both the miners means dealerships of a car deals with that invalidated transaction to make its validate for this purpose. Miner who first succeed to make this transaction valid got the 5 bit coins successfully other one can get invalid transaction. If both the miners picked the transactions at the same time then they both create a blocks in which they tried to pick the transaction and the one who first get the transaction in his block will get the transaction and vice versa.

Question 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.

In this question, I am going to explain the blockchain and how block hashes work.

First, I visit the Blockchain Demo , then go to the blockchain section here I got the interface that I attached below. In this attached screenshot you can see that blockchain has 5 blocks in which each block has a specified block number. Also each block contains Nonce, Data Portion and the hash of previous block. Hash of previous blocks helps to linked the blocks with each other.

For a better grasp of the hash technique, look at the below screenshot. You can see that the first block has a previously hash of zero since it is the first block. Because it is the first block, its previous hash is commonly zero, thus the first block of a blockchain is also known as the Genesis Block. While in the second block you can see it contain the hash of block one and that is for to linked these blocks with each other.

Hash of First Block.

Previous Hash :

Previous hash of Block 1 is 000000000000000000000000000000000000000000000000000

Hash :

Hash of Block 1 is 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

Hash of Second Block.

Previous Hash :

Previous hash of Block 2 is 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

Hash :

Hash of Block 2 is 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

Similarly the 3rd block has previous hash of block 2 and also has it's own hash. Now the hash of block 3 becomes the previous hash of block 4 and block 4 also have its own hash too.

Now putting the data in to the blocks, When i entered the data you can see the hash of both the blocks got changed. So it clarifies that when we enter a new data in blocks it automatically create the new hash.

Mine provides the corrects nonce value and valid hash that makes a block validated.

Now you can see in above screenshot, I clicked the button mine button so after that blocks get validated and it gave me the correct nonce value and a valid hash with the data that i entered before.

Question 6.

What Is Race Attack in blockchain? OR What Is Finney Attack in blockchain? OR What Is Vector76 Attack in blockchain?

Race Attack :

It's one of the ways of double spending. Attack Race where a bad actor triggers a reorganization, enabling the same coins to be spent twice. When a bad actor produces a copy of a prior transaction that has already been confirmed in a blockchain and then utilizes that copy to make further transactions, this is known as a race attack. By reversing their earlier transaction, the attacker would be able to spend an asset many times. Only if the receiver acknowledges an unsettled transaction will the Race attack be achievable. The attacker has now executed many transactions. The miners would approve a few of their transactions and discard the rest.

Question 7.

Limitations/disadvantages of Blockchain.

Disadvantages of Blockchain.

• The first disadvantage is that blockchain is complicated due to the lack of a central server. You have numerous machines to coordinate, and there are various algorithms to choose from. In general, the notion of blockchain is complicated, but once you start working on it, a lot of things become obvious.

• Another issue with blockchain is the concept of key management, as blockchain is based on cryptography, which requires that various keys exist. You have public and private keys, but while interacting with the private key, you face the danger of someone else gaining access to it.

• People are unaware of the genuine usefulness of blockchain and how it may be used to various circumstances. Furthermore, there is a limited pool of technical talent accessible many developers may lack blockchain knowledge.

• Blockchain is immutable, which means you can't make any changes to other records. This is great if you want to maintain the integrity of your records and ensure that no one tampers with them. However, if you need to make any changes or go back and reverse anything, it's a hassle.

• Another downside of blockchain is its high energy consumption. Energy consumption is the primary costing element for blockchain. There are also certain regulatory difficulties, which means that many countries do not recognize it.

• The technology is not mature enough, and creating decentralized apps on the blockchain is a bother. The development firm is small, thus accessible code samples don't function, problems go unnoticed, and so on.

Question 8.

Conclusion(Overall understanding of Blockchain.)

Conclusion.

I conclude that professor gave us a very informative lecture that helps us to learn more about the blockchain, how blockchain works , types of blockchain , hashing function in blockchain and much more. These days, blockchain technology is quite popular. A blockchain is a series of interconnected blocks that store data. A blockchain is a decentralized ledger that is accessible to anybody. They have several intriguing features, such as the fact that once data is fed into the system, changing it is extremely difficult. Each block contains data, as well as the block's hash and the preceding block's hash. The kind of blockchain determines what data is kept inside the blocks. A hash is a number that can be compared against a fingerprint. When you add something to the block, the hash changes. In other words, hashes are quite valuable when it comes to detecting block modifications. The hash or prior block is the third element within each block. This essentially generates a chain of blocks, and it is this approach that ensures the security of a blockchain. Also blockchain has some demerits that I explain above.

Specific mentions to ;
@stream4u