In extremely simplistic terms, blockchain is a decentralised, trust-less system/network which is immutable, transparent and is not dependant on any one entity as a broker of trust.
A) What we mean by trust-less here is that, you as a participant don’t have to trust anybody to store your information or make transactions etc. the foundation of this network is proof and not blind trust. A trust-less system has the following characteristics:
- Open: Nobody has to rely on any intermediary or third-party.
- Borderless: There are no borders/ boundaries to the application of this technology.
- Transnational: The technology is not about any nation-states, it is a network.
- Neutral: It isn’t serving the goals of any organisation. The consensus rules are followed neutrally.
- Censorship Resistance: It is impossible for any actor to censor, blacklist or prevent users from participation in the network.
These characteristics are essential to term a technology as a blockchain, absence of any one of these characteristics is NOT a blockchain technology.
Each and every participant of this network has an equal say in the network regardless of sex, age, religion etc.
We have seen what is the essence of blockchain i.e. a trust-less network, now let us see what actually the term ‘blockchain’ means.
A block contains three essential things:
- Hash: a hash is a 64 digit cryptographic alphanumeric code which is unique for every block.
- Data: the data you want to store in a block. for eg. if the blockhain consists of names then, when you write your name in the network it creates a new block with the same data, and also a unique 64 digit hash code as discussed earlier.
- Hash of previous Block: to form a chain it is necessary to connect each block with the unique 64 digit hash of the previous block. If the hashes don’t match then the block is invalid and won’t be registered.
The first block of the chain is called a genesis block.
B) Immutability: due to the simple fact that once a block has been published in the network it creates a unique 64 digit hash, the system is immutable. for eg, a chain consists of 5 blocks presently. I try to change the contents of the 3rd block, a new hash will be generated for this edited block which will not match with the ‘previous hash’ of the 4th block as it has already been published in the past. hence the change will not be approved by the blockchain.
You can generate your own hash to test this out at hash calculator.
C) Transparency: as a participant of a blockchain, I have the complete history of the chain from the genesis block (first block) to the newest and future blocks, hence the chain is completely transparent.
Something interesting to know here is that a new block has to be validated by the participants of the blockchain. This is the consensus algorithm which is different for every blockchain network. Assume, for a new block to be published 6 nodes (participants) have to validate that block i.e. verify that the block holds true, out of hundreds of nodes of that blockchain.
There are various methods to prove the block, like Proof-of-work, Proof-of-stake etc. and this process of validating a new block is known as ‘mining’. To speed up and attract more miners an incentive is provided to these ‘miners’. These terminologies have been discussed in detail in separate articles.
As new blocks are validated and published the chain of blocks grows.
To conclude, I would like to re-iterate the fact that the blockchain technology is completely transparent, immutable and trust-less, leading us from a centralised network to a decentralised system where every node is equal.
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