image edited in pexelLab

Introduction

Steem greetings everyone in this cryptoacademy Community, hope you are all doing great. It's me again Chia Bertrand Fuchi with the username @chiabertrand. I want to give a special thanks to my genius professor @stream4u whom have brought up a very interesting topic this week. After going through it, I'm extremely happy to be submitting my homework as you can s e below.

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

The word Block in layman's Understanding simply means a huge material such as stone,wood etc but we Also know that block can be something like a building that is divided into many apartments. The word Chain simply means a sequence of materials that are link or Join together to secure something. Now the word Blockchain can simply means a building that has an interconnection of rooms that is link together to secure something

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Now let's talk of blockchain technology in a centralized and decentralized system. First of all we need to know that Blockchain is a system of receiving information, recordings the information, processing the information and securing the information in a way that it's extremely difficult for hackers, fraudsters or theft to steal or hack the system

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Now Blockchain in centralized system. Here clients turn to store most of thier information but in a record inside a book which is very dangerous because once the book is stolen by thefts or missing, your account will eventually be at risk but in Decentralized Blockchain system, everything is so unique and diverse as the block receive, record and stores information that are are link to other blocks which will now form a network system. We can now see here that Blockchain is an open source distribution of ledgers that are use to record all the transactions between different users in the system

let me go deeper on the blockchain system

pixabay image source

In a Decentralized system, total control and decision making is directly from a centralized entity to a distributed network system which can be a group of organization or individuals. In a blockchain decentralized system of technology, the network turns to make a great effort so as to keep trust and faith wit all it's users

let's talk of some importants of a decentralized Blockchain

Optimization of resource distribution: it will definitely help in optimizing the distribution of network resources in a way that all transactions in the system will go smoothly without any interferenc and this process is always consistent as users can do their transactions at anytime and any place

It improves the restoration of data structure: In a blockchain decentralized system, the central entity always exchange data with its users which in turn is transmuted and stored in each users data structure. When ever the data is converted, it exposes the chance for incorrect data or data loss to enter the workgroup

It provides the means for a trustless surroundings in the blockchain transaction: here all the users that ere involved in the system turns to trust each other so much because there is transparency and most of all no third party is involved in other to execute or initiate a transaction.

Types of blockchain

They are basically three main types of blockchain which are Public, Private, Hybrid or consortium Blockchain.

a) Public Blockchain: it is a system of blockchain where everyone having access to internet can start making a legal transactions with different blocks as there is no restrictions here and it make good use of the distributed ledger technology in a way that data is never Stored only I one place as it is distributed all over the whole network system. A good example of a public place is Bitcoin and Etherium. Here any user can buy and sell his or her coins without necessarily revealing then selfs.

There is high level of transparency here because all transactions are open in a way a user can have access to another users account without necessarily asking there user. So once s user is available in this network system, he or she can access all other accounts but it's also highly secured as all the data are encrypted in a process known as cryptgraphy.

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b) Private Blockchain: here, it is only the central entity that regulates affairs as transactions are only done when invited and users need to take permission before conducting an official inspection of the Blockchain. Here, transactions are extremely very fast since it has less users as compared to a public Blockchain. A very good example of this Blockchain is the Hyper-ledger fabrics of the Linux Foundation because of the it functions. Once a user writes someone here, it can never be deleted again as it is extremely immutable.

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c) Hybrid or consortium Blockchain: It is the combination of both the private and Public Blockchain. It is super scalable because it can handle data transactions in a high speed rate and the nodes have access to the data which is stored in the blockchain

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2) What are the benefits of blockchain?

• It is highly secured because all the data within it is encrypted in a process known as cryptgraphy So due this encrypting, it is almost impossible to hack a users account
• All transactions here are done In less than no time as a multiple transactions can be handled in in seconds or even less
• It is a Decentralized structure where there is no central government that have to govern or initiate any transactions approval
• The blockchain create trust between users.due to this, a user can share his/her data to another user without passing through a middle man
• It reduces costs as compared to the Banking system where the third party involved always put charges with both the sender and the receiver. So in a blockchain system, it requires just little charges for the receiver when withdrawing
• It is highly Immutable because once data is written here, it will be recorded and can never be deleted again no matter what.
• Here, one has the full control to do what ever he/she likes with their accounts as they can alter and initiate a transaction at any time and any place he/she wants
• Since it is visible, it can also be traceable so if one mistakenly sends his/her funds to another account, he can trace it an know the user whom he mistakely send the funds to.

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3) Explain Blockchain Distributed ledger.

Blockchain moves only within an encoded decentralized or Distributed data base system which in turn act as a ledger as all the data collected within the system are recorded and encrypted in a cryptographic manner. Here, all transactions can be viewed by the general public and there is no third party involved in other to initiate a transaction, so once the two user come in agreement with their transaction deals,they sender initiates it and it start processing automatically

The blockchain distributed ledger has a data base that occurs at a multiple time and can be accessed and utilized by multiple user accross the entire world. One of the most unique way of a Distribution ledger is the high level of security the system has. There is trust between the user because of the high level of security as a user can send his/her fun to another user without necessarily knowing the identity of the other user.

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

Double spending In blockchain is the process where a block chain day is drastically alterd and all the funds are eventually stolen by thefts. Here, the Crypto currency may be use in a transaction at multiple times with thesame amount of the Crypto asset simply because there is no central authority that is authorized to check the the genuine digital currency such that there is no possibility of a user to double send his or her currency to another user. Some typical examples of this double spending are Vector, Finney and Race Attacks

Let's see how Bitcoin Blockchain can handle Double Spending

Bitcoin has a block of files which accepts process and stores information permanently just like the distribution ledger where by information from the block is always added to the ledger every seconds or less and each node will always maintain a copy of the blockchain ledger.

So now Bitcoin has been able to handle this problem by the Introduction of the Blockchain technology where each blockchain node is distributed geographically which alters all transactions validation by always confirming the transaction and also sure all the transactions are always valid a degree of complexity of a machine system.

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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.

We should know that Blockchain works by including the entities of the previous block into the entities of the next block in other to create an immutable chain which can't be broken. But as more and more blocks are added, the key that will keep the block chain data is only through an algorithm call **Hashing ** which combines together with more stronger or solid data structure call Merkle Tree

Let me take you to a Demo version in other to show you how the Block hashes works in a blockchain

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All the structured Blockchain have nonce and Block numbers then with hashes which are subdivided into two which are the previous and the current hash.this image below shows what I'm trying to say👇

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Now let me explain something from all the images above in the block1 and block 2 hashes. From the block 1 image above, we can see that it has a previous hash of it is 0000000000000000000 and it also has a hash of 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf. I happens so simply because we have applied something known as the Genesis block. So all the first block of the Blockchain will equally have the Genesis block.

Then for block 2, we can see that it has a previous hash of block one then also has its own hash. For example block 2 has a hash of 00012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19 then with a previous hash of 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf . From here, we can see that the two blocks are interconnected

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From the image above, we can see clearly that block 3 has a previous hash of block 2 plus it's current hash and block 4 has previous hash of block 3 plus it's own hash.

Let me go deeper, we know that block 2 has a previous hash of 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19. Then block 3 has a previous hash of 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19 then with its own current has of 0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf

Then block 4 has a previous hash of 0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf then with its own current hash of 0000ae8bbc96cf89c68be6e10a865cc47c6c48a9ebec3c6cad729646cefaef83

We can now see clearly that they are interconnected as they have a common link

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Let me go deeper by adding data to the block in in the block chain since I didn't generate any data in the above images. So here, adding data to the block, it will eventually generate a new hash for its previous block as it will now be necessary for mining

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From the image above, we can see clearly that the nonce doesn't correspond to the block hash as we can see how the interface changes to red by indication of an invalid block hash.

Block1
The Nonce is 111316
And the hash is. 9832c0400fb19191af94809ffb07d7b5a9a5abf96ef30f657bdf13672114ed6e

Block2
Nonce is **35230 **
Previous is 9832c0400fb19191af94809ffb07d7b5a9a5abf96ef30f657bdf13672114ed6e

and it's hash is 227f2d3b2968031990647fc3683d9309b666c0fc412dda8d8c3d99e15992c121

What we should do now is to change the Nonce in block1 and see if the block can generate a different hashes and previous

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This image above shows that I have changed the Nonce in block1 and the system have geneted different hashes and previous

It's new nonce is 11475

It's hash is 22f7207a654112dd783fb41da6a8defd92c4321e3fbdd06360376178b4b139cc

It's nonce is 35230

It's new previous is 22f7207a654112dd783fb41da6a8defd92c4321e3fbdd06360376178b4b139cc

And it's new hash is 9ca292fa32eeb75cfac9db504602094e9a8846bb1b2a098f4f875e2c884ae6de

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Let me take you to the mining process in a block chain system now

We should know that mining is the method of using very powerful computer machines to declare a legally valid results in a blockchain. This computers are always highly rated and extremely has a high speed and doesn't consume a lot of Power

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Here I tried clicking on the Hash to see if it will generate then I click on mine

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After clicking on mine in block1, it took some few seconds to load and the mining automatically solve the the algorithm in block1 and eventually gave me the correct block output which therefore also automatically turns green

The data I wrote was Christiano ronaldo and the it gave me a correct nonce of 77058
Then with a correct hash of 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf and previous still had to to remain at 0000000000000000000000000000000000000000000000000000000000000000

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I then proceeded to mine block2 which also turn green meaning the mining process was successfully as it gave me the correct Nonce as 28177 and the previous was 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf It's current has was now 000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

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We can see here that there was a successful mine as there is an interconnection between all the blocks because the previous of block2 is the Hash of of block1 and previous of block3 is the Hash of block2, the chain continues in a sequence till the last block. We should also know that block1 is considering as the Genesis block sice it's previous always values always stands at zero, ie 0000000000000000000000000000000000000000000000000000000000000000

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

a) what is Race Attacks in blockchain

This is a situation where by a user is attacked by scamers or hackers as he/she can mistakenly double-sends his/her funds to different suppliers but very similar at a very fast rate. Or can be a situation where by two transactions can be initiated by using the same amount coins at thes ame period of time by spending the coins twice deliberately.

b) what is Finney Attacked

It can be termed as the type of attacked that happens when a user receives and accepts a transaction when it is not finally established or confirm within the network system. Here, the attackers takes full control of the node as they can make fake transactions by double-spending the coin to anothers accounts. Here, the hackers go ahead to create two different transactions as one turn to credit him(hackers) and the other one is by crediting the innocent.

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c) What Is Vector76 Attack in blockchain?

This when hackers Attacks a system by creating two nodes which one is connected exactly to exchange node while the other is connection to a group organization peers as they will go ahead to prepare a crypto asset will be generated by them to the all the recievers within the network system

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7) Limitations/disadvantages of Blockchain.

• There is usually issue of double-spending as transactions can be done illegally due to high level of scamming and hacking
• The data here is immutable as it can't be deleted once put into the blockchain system even if it was a mistake
• Users here are their own bank which is extremely risky because a user will need to keep all the private keys in a way it should never be missing, stollen or hacked. If it's missing, the user will eventually never recover back his or her account, and if it's hacked or stollen, the user will eventually lost his/her assets
• During mining, there is very high amount of power needed to mine which is really a big disadvantage
• It is too costly because implementing a blockchain technology is a huge sacrifice as it requires a lot of investment from the organization that wants to open it

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Conclusion

• After going through the lessons taught by our professor @stream4u , I was able to come out with some benefits of the Blockchain and the main difference between the centralized and decentralized system of Blockchain. I went further to discuss about the advantages of the decentralized system over a centralized system where there is high level of security, transparency and trust between users

• I have come to know more about the various types of blockchains and thire importants which are the public, private and the consortium or hybrid blockchain

• I also learn how Blockchain double-spending can be solved by simply using blockchain technology since the node validation needs only to be approved by the miners before a transaction can be approved.

• special thanks to professor @stream4u who provided me with the interesting lessons which have guided me in completing this homework task.