What is blockchain?
we are going to see all the topics which are mentioned below and by the end of this blog, you will have a idea about what is blockchain.
Blockchains are incredibly popular nowadays.
- what is a blockchain?
- how do they work?
- how to secure it?
- The evolving of blockchain
- the conclusion
What is blockchain?
like the name indicates, a blockchain is a chain of blocks that contain information.
this technique was originally described in 1991 by a group of researchers.
then it was originally intended to timestamp digital documents so that it’s not possible to back them or to tamper with them. almost like a notary.
however, it went by mostly unused until it was adapted by Satoshi Nakamoto in 2009 to create the digital cryptocurrency bitcoin.
a blockchain is distributed ledger that is completely open to anyone.
they have an interesting property
once some data has been recorded inside a blockchain, it becomes very difficult to change it.
how does it work?
if we take a closer look at a block, each block contains.
- hash of the block.
- hash of the previous block.
the data that is stored inside a block depends on the type of blockchain.
the bitcoin blockchain stores the details about a transaction in here.
such as the sender, receiver and amount of coins.
2.Hash of the block
a block also has a hash. which you can compare a hash to a fingerprint.
it identifies a block and all of its contents and it’s always unique, just like a fingerprint.
once a block is created it’s hash is being calculated.
changing something inside the block will cause the hash to change.
i.e hashes are very useful when you want to detect changes to block.
if the fingerprint of a block changes, it no longer is the same block.
3.Hash of the previous block.
the third element inside each block is the hash of the previous block.
this effectively creates a chain of the block and it’s this technique that makes a blockchain so secure.
here we have a chain of 3 blocks.
as you can see, each block has a hash and the hash of the previous block.
block number 3 points to block number 2 and number 2 points to number 1.
now the first block is a bit special.
it cannot points to the previous block because it’s the first one
we call this block the genesis block.
now let’s say you tamper with the second block.
this causes the hash of the block changes as well.
in return that will make block 3 and all following block invalid because they no longer store a valid hash of the previous block.
so changing a single in a block will make all following block invalid
but using hashes is not enough to prevent tampering.
the computer this days are very fast and can calculate hundreds of thousands of hashes per second.
you could effectively tamper with a block and recalculate all the hashes of other blocks to make your blockchain valid again.
how to secure it?
this process called proof-of-work.
it is a mechanism that slows down the creation of a new block.
in bitcoins case:
it takes about 10 minutes to calculate the required proof-of-work and add a new block to the chain.
this mechanism makes it very hard to tamper with the block because if you tamper with 1 block, you’ll need to recalculate the proof-of-work for all the blocks.
so the security of a blockchain comes from its creative use of hashing and the proof-of-work mechanism.
it can be secure by distributing themselves.
instead of using a central entity to manage the chain, blockchain uses a peer-to-peer network.
here everyone is allowed to join.
when some join the network, he gets the full copy of the blockchain.
the node can use this to verify that everything is still in order
now let’s see what happens when someone creates a new block.
that block is sent to everyone on the network.
each node then verifies the block to make sure that it hasn’t tampered.
if everything checks out, each node adds this block to their own blockchain.
all the nodes in this network create consensus.
they agree about what blocks are valid and which aren’t.
block that is tampered with will be rejected by other nodes in the network.
to successfully tamper with a blockchain you’ll need to tamper with all block on the chain.
redo the proof-of-work for each block and take control of more than 50% of the peer-to-peer network.
only then will your tampered block become accepted by everyone else.
so this is almost impossible to do.
the evolving of the blockchain
blockchain also constantly evolving.
first, the blockchain uses to have like data, hash fo the block, hash of the previous block
after that the security elements like proof-of-work and peer-to-peer network
now one of the most recent development is the creation of smart contracts
these contracts are simple programs that are stored on the blockchain and can be used to automatically exchange coins based on certain conditions.
the creation of blockchain technology peaked a lot of people’s interest.
and other realized that the technology could be used for other things as well.
like storing medical recording, creating a digital notary or even collecting taxes.
so now you know what is blockchain is, how it workes a basic level and what problems it solves.
if you like our article, please consider sharing with your friends and family