CryptoAcademy Season 4 Beginner's Course - Homework Post for Task 4 : Definition of Blockchain, How data is protected on blockchain, meaning of data, hash, and previous hash tag.

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WRITE THE DEFINITION OF BLOCKCHAIN AND HOW IS BLOCKCHAIN PROTECTED FROM HACKERS?

AND WRITE DETAILS ABOUT DATA, HASH AND PREVIOUS HASH TAG AND EXPLAIN THROUGH SCREENSHOTS

INTRODUCTION

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I plead for your endulgence as we tour through the archive of historical data.

The blockchain system we have today was designed by two noble researchers in 1991. The aim was for documents authentication, in other words, it was made to operate as a digital notary.

But it was yet to be known, or rather rampant worldwide. All the long from 1991, the blockchain gained recognition worldwide in 2008 sequel to its adoption by Satoshi Nakamoto with respect to his calculated decision to invent the first chryptocurrency which is the bitcoin and aswell the most popular presently.
Compatibility of the program with the Blockchain was in top consideration, such that there was no conflict in operation.

And the question is, what is Blockchain?

WHAT IS BLOCKCHAIN?

On a shabby definition, blockchain simply means a chain of blocks which contains informations.

For a better understanding of the compound word, "blockchain" I want to explain the Component words in isolation.

The word blockchain comprises of two words which are "block" and "chain".

With regards to the subject matter, a BLOCK is seen as a book or document where informations or records of certain transactions that took place on the blockchain are contend.

Then talking about chain. It is simply something after something with a link.
In other words, a chain literally means a series of things ( materials, events, etc) which are linked or interconnected together.
Thus, blockchain is a series of blocks linked together.

Then to put it the appropriate way, we can say that, blockchain are blocks arranged in series that contains transaction history.

HOW BLOCKCHAIN IS PROTECTED FROM HACKERS

For a dependable security, the blockchain system had adopted a technology which is distributed enabling it to save data. The data is stored in such a way that there would be no form of modification, neither can it ever be eliminated. The blockchain first gives priority to security, before carrying out any of it's operation. And it's ability to achieve the required strong security for our data to be saved and aswell equip itself with an unquestionable database is dependent on the following features.

• PROOF OF BRAIN, PROOF OF WORK, PROOF OF STAKE(Consensus Algorithm)

All these are cryptographic protocols which is very crucial in validation of transactions. Its function is to make a request for multiple processes of genuity before a transaction can be validated and in that measure, seal any loophole for intending hacking activity.

For intance, Bitcoin makes use of PoW from which the minners creat the blocks, solves difficult challenges that are mathematically related with the use of high technological gadgets and processors that are modified for minning operation.
All the stakeholders in the platform will need to air their views to authenticate the rest as right or wrong, that is, after the problem had been solved.
If the result is affirmed as correct, then novel block becomes a plus to the chain followed by a consolidation of the information. And ofcourse, the minner is rewarded for the good job.

• BLOCKS

The blocks just as I already pointed earlier, is like a book or document where informations or records of certain transactions that took place on the blockchain are contend.

There are the fundamental components that attributes huge importance to the blockchain. They are modified via consensus algorithms to enhance functions like verification processes as well as functions via its fundamental structure which is incharge for aggregating diverse transactions so that they can be distributed in each node of the entire blockchain.

• ARCHITECTURAL DECENTRALIZATION

The most comfortable replacement for the federated financial ecosystemsystem and government is the blockchain. It has it's own autonomy so that it's not subjected under the control of a central body but instead, operates more like democracy, insuch a way that it is owned and controlled by all.
In that aspect, issues of abuse of power, financial dependencies and tax cases becomes a history.

Therefore, since it is a Decentralized system, it adopted the peer to peer (P2P) network. A network that allows anyone and everyone to have a fair share by featuring as a node, and thus, with the use of computer or any other database to receive all the copies of the blockchain.

• LARGE NUMBER OF NODES

Making reference to what I said earlier, every single user is in possession of a complete copy of the database, making the information to be always available and accessible immediately when ever need arises.
Unlike the conventional financial system like banks that usually have a single manger, the accounts of the enormous bank of nodes of the blockchain are managed by the individual users.
This simply means that they are multiple eyes waching at all point in time so that, paraventure there is any attempting alteration of information from hackers in some blocks, the other users will be quick to cancel such fraudulent blocks including all the blockchains that comes after it. In that regard, the security of the system is therefore in the hands of all users or stakeholders in the system.

STRUCTURE OF A BLOCK

The structuring of the block is done in such a way that each individual block is able to accommodate diverse kinds of information. And aswell, it's able to contain both it's own hash and hash of previous block.

The uniqueness of the block its constituent elements. These elements are specialized features that are important for the verification of informations that are necessary for each block.
These elements includes: Hash, Data and Previous block hash.

• DATA

It's the kind of blockchain you are dealing with that will determine the kind of data to be stored in it.
For example, if a blockchain is designed for the education sector, it record taking will be on student's data like, age, gender, address, course of study etc.

In the other hand, if a blockchain is designed for the purpose of financials, just like Bitcoin, it prioritizes on data like
• The sender
• Time,
• Amount of money, and
• Receiver into account

Now, anytime a transaction is completed, all the data as listed above are recorded in the blocks.
Hence, for the purpose of security and equity, all stakeholders/users of the blockchain receives their own copy of the transaction. This makes it impossible to alterate any data in any block because you will need to aswell effect a change in the records of the copies that are in other user's position in the entire blockchain.

You can locate the data on the block headers which is where they are stored. Storing the data in the header of the blocks makes it easier for identification by the nodes.

• HASH

The hash which is one of the most important Components of a blockchain can simply be defined as a number used in identifying a block.
Hash code is very unique and dynamic in such a way that a hash found in block A will differ from the one found in block B.
Just imagine how human finger prints differs from one person to another, that's how hash is to the various blocks.

Hence, informations inside a block can only be verified using the hash code, regardless if these informations in the block is right or wrong.

Hash found in the Bitcoin blockchain is characterized of a randomly generated chryptographic algorithm that is used to identify and differenciate a block from another in a blockchain.

Some of its principal operations includes the conversion of blocks with different unique features into a series of acceptable dimension regardless of data input.

The assistance of the hash is also necessary to authenticate the integrity of transactions that took place in the blockchain.
In transaction process, the different nodes in the network have to verify the transaction hash before a transaction would be accomplished.
Thus, if in any case, the other nodes observes an unscrupulous activity in the process of the transaction, they will immediately employ automatic termination of such operation.

In addition, the operation of the hash is not just limited on transaction information but it also takes key function to encrypt the text messages sent to the blockchain network in such a way that only the senders and receivers will have access to the to the information.

• PREVIOUS HASH

Within the data of a new block is where You can find the hash of a previous block
It's presents is required to create a long chain of blocks, starting from block 0.
Therefore, Incase there is any attempt to make a change in a particular block, it would also require you effect the change for all other subsequent block generations which is very cumbersome, and somehow near impossible.
This is one of the unique features that makes it very difficult and complicated to be faked.
And so, we have a Decentralized blockchain.

EXPLORE BLOCKCHAIN AND PROVIDE SCREENSHOTS

Exploring the blockchain I discovered that there were total of 5 blocks excluding the 0 block. From block 1 to 5.
But I will be using 3 blocks for illustration.

Below are the informations in the Blockchain

FOR BLOCK ONE

• Block:#1

• Nonce:11316

• Data:

• Prev hash:0000000000000000000000000000000000000000000000000000000000000000

• Hash:
  000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

_

FOR BLOCK TWO

• Block:#2

• Nonce:35230

• Data:

• Prev: 000015783b764259d382017d91a36d206d0600e2cbb3567748f46a33fe9297cf

• Hash:
  000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

_

BLOCK THREE

• Block:#3

• Nonce: 12937

• Data:

• Prev:
  000012fa9b916eb9078f8d98a7864e697ae83ed54f5146bd84452cdafd043c19

• Hash:
  0000b9015ce2a08b61216ba5a0778545bf4ddd7ceb7bbd85dd8062b29a9140bf

_

Good observation of the informations in the various blocks above shows that there is a synergetic or uncompromising relationship between a block to another in the Blockchain in such a way that the hash of a block becomes the previous hash of the subsequent block.
The data collum is always blank to permit imputation of any data of your choice. Hence, any data you supply in any of the block would automatically change the hash in the other blocks, and when this happens, the previous blocks also respond to the change automatically but the nonce remains thesame.
For example. I typed my steemit username (vibrant6689) in the space provided for data in the block 1 but it effected change in other blocks as seen below.

FOR BLOCK ONE

• Block: #1

• Nonce: 11316

• Data: vibrant666

• Prev:
  0000000000000000000000000000000000000000000000000000000000000000

• Hash:
  99483d813cb64e5dd23137124f11712aee0858c066a54f189b1bbf4bdfade61b

_

FOR BLOCK TWO

• Block: #2

• Nonce: 35230

• Data:

• Prev:
  99483d813cb64e5dd23137124f11712aee0858c066a54f189b1bbf4bdfade61b
  Hash:
  d517441199dc4732ed918669adacca5a8f5306aabb41fe64934361d1edf04515

_

FOR BLOCK THREE

• Block: #3

• Nonce: 12937

• Data:

• Prev:
  d517441199dc4732ed918669adacca5a8f5306aabb41fe64934361d1edf04515

• Hash:
  b34372ec34b4f59a675ec99f018b5cf98f3b3ec40c54cf6ac8c3fff601d67f5d

COMPARISON

No data inputted	Data inputted

Look vividly into the into the images, you will see the change in harsh and Previous harsh.

NOTE All images about blockchain are Screenshots from blockchain demo

CONCLUSION

The emergence of blockchain is a very welcome development. A system that had brought peace of mind and self reliance to humans. You do not need to que in line any longer before you can access your money neither do you have any case to answer again with the government nor tax to pay.

Regards to professor
@yousafharoonkhan
@steemitcryptoAcademy