What is Block Chain?
A blockchain, originally block
chain, is a continuously growing list of records, called blocks, which are
linked and secured using cryptography. ... It is "an open, distributed
ledger that can record transactions between two parties efficiently and in a
verifiable and permanent way".
All of a sudden, Blockchain is
everywhere. The technology that
started to power the Bitcoin, is now used for almost everything – from copyrights,
data analysis, security and protection of applications and environments
How Does Blockchain Work?
To start, here’s the simplest
explanation with no metaphors or hyperbole. In the language of cryptocurrency,
a block is a record of new transactions (that could mean the location of
cryptocurrency, or medical data, or even voting records). Once each block is
completed it’s added to the chain, creating a chain of blocks: a blockchain.
Because cryptocurrencies are
encrypted, processing any transactions means solving complicated math problems
(and these problems become more difficult over time as the blockchain grows).
People who solve these equations are rewarded with cryptocurrency in a process
called “mining.”
If you own any cryptocurrency, what
you really have is the private key (basically just a long password) to its
address on the blockchain. With this key you can withdraw currency to spend,
but if you lose the key there’s no way to get your money back. Each account
also has a public key, which lets other people send cryptocurrency to your
account.
Information on the blockchain is also
publicly available. It’s decentralized, meaning it doesn’t rely on a single
computer or server to function. So any transactions are instantly visible to
everyone. That brings us to our first metaphor: the public ledger.
Blockchain Is Like a Public Ledger
If you send Bitcoin (or some other
cryptocurrency) to a friend, or sell it, that information is publicly available
on the blockchain. Other people may not know your identity, but they know
exactly how much value has been transferred from one person to another.
Many people see blockchain as an
alternative to traditional banking. Instead of needing a bank or some other
institution to verify the transfer of money, you can use blockchain and eliminate
the middle man.
“The Internet of Value”
Building off the idea of a public
ledger, another popular way to describe blockchain is as the internet of value.
The idea is pretty simple: the internet made it possible to freely distribute
data online, blockchain does the same thing for money.
Instead of relying on newspapers,
television and radio (which are mainly controlled by big corporations), the
internet gives everyone a voice—for better or worse. Blockchain and
cryptocurrency make it just as easy to transfer money across the world by
bypassing traditional middlemen like banks and even governments.
Blockchain Is Like Google Docs
Here’s a clever metaphor for
blockchain from William Mougayar, the author of The Business
Blockchain: blockchain is like Google Docs.
Before Google Docs, if you wanted to
collaborate on a piece of writing with someone online you had to create a
Microsoft Word document, send it to them, and then ask them to edit it. Then
you had to wait until they made those changes, saved the document, and sent it
back to you.
Google Docs fixed that by making it
possible for multiple people to view and edit a document at the same time.
However, most databases today still work like Microsoft Word: only one person
can make changes at a time, locking everyone else out until their done.
Blockchain fixes that by instantly updating any changes for everyone to see.
For banking, that means that any
money transfers are simultaneously verified on both ends. Blockchain could also
be used in the legal business or architecture planning— really any business
where people need to collaborate on documents.
Blockchain Is Like a Row of Safes
Here’s another useful explanation
from online forum
Bitcoin Talk. This one does a really good job of explaining how
public and private keys work:
Imagine there are a bunch of safes
lined up in a giant room somewhere. Each safe has a number on it identifying
it, and each safe has a slot that allows people to drop money into it. The
safes are all made of bulletproof glass, so anybody can see how much is in any
given safe, and anybody can put money in any safe. When you open a bitcoin
account, you are given an empty safe and the key to that safe. You take note of
which number is on your safe, and when somebody wants to send you money, you
tell them which safe is yours, and they can go drop money in the slot.
Blockchain Is Like DNA
Blockchain is a record of
transactions, spreading across the internet as more people use
cryptocurrencies. Similarly, DNA is a record of genetic transactions and
mutations that spread as life expanded across the earth. Both become more
complicated over time as our DNA evolves and new blocks are added to the
blockchain.
Each blockchain (Bitcoin, Ether,
Ripple) is like as a distinct species (human, chimpanzee, etc.). A blockchain
can also be forked (like with Bitcoin Cash) to create a competing currency in
the same way that two distinct species can share common ancestor.
Of course, changes to DNA don’t
happen easily—scientists believe it takes about a million years for a
genetic mutation to catch on—and building a blockchain isn’t easy, either. The
process of evolution and natural selection is a little bit like mining, a
complicated series of steps that creates something incredible.
Source:
https://drive.google.com/file/d/1wveE9EgrTmXsFl9udXbAiz440cKCxezS/view
http://bit.ly/mCbCPP http://bit.ly/BcGand http://bit.ly/ChIDpp Additional collateral is available at http://bit.ly/CMbcDB
From the Blockchain Guru IBM Fellow Prof C Mohan