Blockchains are pretty popular nowadays. Cryptocurrencies that everyone in this world is raving about are developed with the help of Blockchain. So what is Blockchain?
Blockchain is a method of securely recording data or information which makes it hard to hack or change the system. A blockchain is simply a virtual record of transactions that is replicated and distributed throughout the blockchain's complete network of computer systems.
Each block on the chain comprises a number of transactions, and whenever a new transaction happens on the blockchain, a record of that transaction is added to the ledger of every participant. A blockchain network consists of millions of blocks that are in a constant state of flux.
In this article, we are going to discuss the answers to the following questions:
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What is a block?
A block in a blockchain network is like a link in a chain. In the field of cryptocurrency, blocks are like records that store valid transactions like a page of a record book and are hashed and encrypted into a hash tree or Merkle tree.
Blocks are like the building blocks of any blockchain and they are distinguishable from one another as they have different characteristics. When a block is completed, it makes room for the following block in the blockchain. A block is very secure and is impossible to hack virtually.
How does a block work?
In any cryptocurrency, there are a huge number of transactions occurring every day throughout the world. It is important for the users to keep track of these transactions, and they can do it with the help of blocks. A block contains the recent data and every time the block is completed, it becomes a part of the past and makes room for a new block on the blockchain.
The completed block is a permanent record of prior transactions, and new ones are recorded in the current one. As a result, the entire system enters into a loop that permanently saves all data.
Let us look at an example of a Block
Blockchain can be compared to a regular bank. A blockchain is similar to a record of bank transactions, but a block might be a single transaction confirmation printed out by a bank ATM after you use it. Individual blocks on the blockchain network form a 'ledger,' similar to how an ATM or bank records your transactions. Blockchain, on the other hand, records the chain across all of its users rather than just one. This is comparable to a bank, except the blockchain provides greater anonymity than traditional financial organizations.
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Types of Blocks
There are three types of blocks that exist in different blockchains namely Genesis block, Valid blocks, and Orphan blocks. Let us discuss them in detail.
Genesis means ‘origin’ and rightfully named, genesis block is the first block of a blockchain. The first genesis block was mined by Satoshi Nakamoto in creating bitcoin and released the idea in public in 2009.
Because of the existence of the genesis block, the blockchain may begin to construct its history of operations or Transactions. This fundamental block enables the newly formed block to be linked to a previous state. The blockchain can ensure its immutability through this connection.
This is because of the usage of technologies such as the Merkle tree. This enables the association of the block history with a unique hash associated with those blocks.
Any change, no matter how little, inhibits the verification of the Merkle root is accurate, invalidating part or all of the blockchain's history, depending on the scenario. There are other blocks as well that get layered on top of one another but the genesis block is always the foundation block, hence it is also named Block 0.
The genesis block serves a crucial purpose in allowing network nodes to be synchronized. Synchronization is only feasible when both nodes' databases have the same genesis block. This guarantees that the distributed transaction ledger on the blockchain is the same for everyone, ensuring security.
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When the genesis block came into existence, a debate arose on whether this block was an intentional discovery or a mistake by Nakamoto. It was also questioned if Nakamoto was a real person or just a pseudonym. Although the Genesis Block refers to a web URL that is written into the Genesis Block's code, when activated, that link displays an error message.
The first 50-BTC transaction could not be found in the system's database, thus the spending transaction was denied. As a result, the transaction in the Genesis Block is not recognized as a "genuine transaction" by the original Bitcoin client.
Yet today, the concept of genesis blocks is completely accepted and has started a global technological revolution that is evolving to date. In that respect, the genesis block may be viewed as "The angular stone" of all blockchain technology. As a result, every blockchain has a genesis block, and every blockchain has this "cornerstone" in its history.
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Valid blocks are all such blocks that have been mined and added to the blockchain. To get a valid block, each mined block must get network permission and report as a block that has solved the given cryptographic puzzle.
When the network reaches consensus, the block is added to the blockchain and distributed to all nodes. As a result, every node in the network has a new block and acts as a verification point for it. All the operations and transactions that are happening in any cryptocurrency are allowed by these blocks.
Each valid block contains a sequence of transactions that are validated together with the block. In Bitcoin, for example, each legitimate block contains an average of 2100 transactions. As a result, each transaction in the valid block becomes a confirmed transaction. Every valid block added to the blockchain after that continues to confirm earlier transactions. This ensures that every transaction and block on the network is completely safe. (Source)
Each valid block comes with a data structure that allows this fact to be confirmed. The hash of the block, the Merkle Root, the timestamp, nuncio, the block transaction data, and the Coinbase are all included in the structure. All of this is set up in such a manner that each piece of information can be publicly confirmed.
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Orphan blocks are also correctly named as these blocks are not part of the blockchain network. These are generally generated by two miners mixing blocks at almost the same time, but they can also be caused by an attacker with enough computational power with the intention of reversing any transaction.
The network consensus procedure is invoked at this point to determine which blocks will be verified (included in the chain) and which will be orphaned. Usually, the longest blockchain that contains the most amount of transactions and information will generally be decided on. Hence, making the security process very simple.
Assume a cybercriminal decides to hack the Bitcoin network and cause a convenient fork. To accomplish this, he begins mining blocks in order to receive the compensation of 6.25 BTC for each block. At the same time, it creates a fork in the network that is beneficial to it since it will have its own new blocks. This will let the hacker utilize the funds that he has maliciously obtained and he only engages in a minar raw block of network transition.
But what happens is it leaves every mined block with nothing other than a coinbase. On scanning, the blockchain network will detect which block between the original and the duplicate one will have more information and will choose the original one, thus ruining the game of the hacker.
Of course, if the attacker has more than 50% of the mining power, one may reverse this, but such power is not required to compute an orphan block. It happens all the time, and it is the network's consensus mechanisms that keep us safe from it. Block explorers can track orphan blocks.
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Blockchains are a complex field of study and every company is slowly adopting blockchain as it is one of the safest ways of transaction. Blocks are the fundamentals of blockchain and they make it very difficult for attackers to hack or manipulate cryptocurrencies.
Several central banks across the world are researching the advantages of blocks, blockchains, and distributed ledger technologies.In this article, we have learned what blocks are and how they work. Later, we have explored the three types of blocks available, namely genesis block, valid block, and orphan block.