BLOCKCHAIN TECHNOLOGY

 Introduction:

Blockchain, the record-keeping technology behind the Bitcoin network. Blockchain is the backbone Technology of Digital CryptoCurrency Bitcoin. The blockchain is a distributed database of records of all transactions or digital events that have been executed and shared among participating parties. Each transaction was verified by the majority of participants in the system. It contains every single record of each transaction.

"Blockchain is a distributed, decentralized, public ledger."Blockchain is actually easier to understand than that definition sounds.

What is Blockchain?

A blockchain is a digital record of transactions. The name comes from its structure, in which individual records, called blocks, are linked together in a single list, called a chain. Blockchains are used for recording transactions made with cryptocurrencies, such as Bitcoin, and have many other applications.

Each transaction added to a blockchain is validated by multiple computers on the Internet. These systems, which are configured to monitor specific types of blockchain transactions, from a peer-to-peer network. They work together to ensure each transaction is valid before it is added to the blockchain. This decentralized network of computers ensures a single system cannot add invalid blocks to the chain.

When a new block is added to a blockchain, it is linked to the previous block using a cryptographic has generated from the contents of the previous bock. This ensures the chain is never broken and that each block is permanently recorded. It is also intentionally difficult to alter past transactions in blockchain since all the subsequent blocks must be altered first.

How Blockchain works?

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

Blocks:

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 generated the cryptographic hash. The data in the block is considered signed and forever tied to the nonce and hash unless it is mined.

Nodes:

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.

Every node has its own copy of the blockchain and the network must algorithmically approve any newly mined block for the chain to be updated, trusted, and verified. Since blockchains are transparent, every action in the ledger can be easily checked and viewed. Each participant is given a unique alphanumeric identification number that shows their transactions.

Miners:

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

In a blockchain every block has its own 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 generated and 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.

Is Blockchain Private?

Anyone can view the contents of the blockchain, but users can also opt to connect their computers to the blockchain network as nodes. In doing so, their computer receives a copy of the blockchain that is updated automatically whenever a new block is added, sort of like a Facebook News Feed that gives a live update whenever a new status is posted.

Each computer in the blockchain network has its own copy of the blockchain, which means that there are thousands, or in the case of Bitcoin, millions of copies of the same blockchain. Although each copy of the blockchain is identical, spreading that information across a network of computers makes the information more difficult to manipulate. With blockchain, there isn't a single, definitive account of events that can be manipulated. Instead, a hacker would need to manipulate every copy of the blockchain on the network. This is what is meant by blockchain is a "distributed" ledger.

Is Blockchain Secure?

The whole point of using a blockchain is to let people-in particular, people who don't trust one another-share valuable data in a secure, tamper-proof way. That's because blockchains store data using sophisticated math and innovative software rules that are extremely difficult for attackers to manipulate.

But the security of even the best-designed blockchain systems can fail in places where the fancy math and software rules come into contact with humans, who are skilled cheaters, in the real world, where things can get messy.

To understand why to start with what makes blockchains "secure" in principle. Bitcoin is a good example. In Bitcoin's blockchain, the shared data is the history of every Bitcoin transaction ever made: an accounting ledger. The ledger is stored in multiple copies on a network of computers, called "nodes."

Each time someone submits a transaction to the ledger, the nodes check to make sure the transaction is valid-that whoever spent a bitcoin had a bitcoin to spend. A subset of them competes to package valid transactions into "blocks" and add them to a chain of previous ones. The owners of these nodes are called miners. Miners who successfully add new blocks to the chain earn bitcoins as a reward.

The final security element is that the hashes also serve as the links in the blockchain: each block includes the previous block's unique hash. So if you want to change an entry in the ledger retroactively, you have to calculate a new hash not only for the block it's in but also for every subsequent block.

And you have to do this faster than the other nodes can add new blocks to the chain. So unless you have computers that are more powerful than the rest of the nodes combined(and even then, success isn't guaranteed), any blocks you add will conflict with existing ones, and the other nodes will automatically reject your alterations. This is what makes the blockchain tamperproof, or "immutable."

Hope this found you all very interesting and helpful. Stay connected for more articles.

Thank You.

~Jinal Menpara