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Essay on Cyber Security

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“Blockchain is a distributed, decentralized, public ledger.” Or Blockchain technology is most simply defined as a decentralized, distributed ledger that records the provenance of a digital asset. We can understand the blockchain easier, more perfect than this definition. 

If this technology is so complicated or complex, then why we call it “blockchain?” At its most basic level, blockchain is simply just a chain of blocks, but not in the traditional sense of those words. When we talk about the words “block” and “chain” in this context, we are talking about digital information (the “block”) stored in a public database (the “chain”). 


Blockchain, sometimes mentioned to as Distributed Ledger Technology (DLT), makes the history of any digital asset unalterable and transparent through the use of decentralization and cryptographic hashing.  

A simple example for understanding blockchain technology is a Google Document. When we create a document and share it with a group of people, the document is distributed instead of copied or transferred. This creates a decentralized distribution chain that gives everyone access to the document at the same time. 

Of course, blockchain is more complicated than a Google Document, but the example is apt because it illustrates three critical ideas of the technology:

1. Digital assets are divided instead of copied or transferred.

2. The asset is decentralized, allowing full real-time access.

3. A transparent ledger of changes preserves the integrity of the document, which creates trust in the asset.

Blockchain is an especially promising and revolutionary technology because it helps reduce risk, stamps out fraud and brings transparency in a scaleable way for myriad uses. 

Blockchain consists of three important concepts: blocks, nodes and miners.


Every chain consists of multiple blocks and each block has three basic elements:

· The data in the block.

· A 32-bit whole number called a nonce. The nonce is randomly generated when a block is created, which then generates a block header hash. 

· The hash is a 256-bit number wedded to the nonce. It must start with a huge number of zeroes (i.e., be extremely small).

When the first block of a chain is created, a nonce generates the cryptographic hash. The data in the block is considered signed and forever tied to the nonce and hash unless it is mined.  


One of the most important concepts in blockchain technology is decentralization. No one computer or organization can own the chain. Instead, it is a distributed ledger via the nodes connected to the chain. Nodes can be any kind of electronic device that maintains copies of the blockchain and keeps the network functioning. 


Miners create new blocks on the chain through a process called mining.

In a blockchain every block has its unique nonce and hash, but also references the hash of the previous block in the chain, so mining a block isn’t easy, especially on large chains.

Miners use special software to solve the incredibly complex math problem of finding a nonce that generates an accepted hash. Because the nonce is only 32 bits and the hash is 256, there are roughly four billion possible nonce-hash combinations that must be mined before the right one is found. When that happens miners are said to have found the “golden nonce” and their block is added to the chain. 

Making a change to any block earlier in the chain requires re-mining not just the block with the change, but all of the blocks that come after. This is why it’s extremely difficult to manipulate blockchain technology. Think of it is as “safety in math” since finding golden nonce requires an enormous amount of time and computing power.

When a block is successfully mined, the change is accepted by all of the nodes on the network and the miner is rewarded financially.


Nowadays, we hear and see the discussion and News of the bitcoin that somewhere some people are implementing religious act and somewhere people discussing government changes and laws on bitcoin but unfortunately and sadly there is no one talk or think about the main and basic technology “Blockchain” where from the bitcoin and more cryptocurrencies like bitcoin are created or presented. so if we focus on blockchain and be Expert and professional then it will be very helpful and great for our future and career.