Let’s start with a story:

     Let’s suppose you wish to buy a house. For that you’ll need money, thereafter you’ll need to sign an official document termed a “Sales Deed” with the owner of the property. After signing up the contract you’ll be able to register the property and entitle it to your name through a government institution. All this data would be stored by the government official by either of the listed methods:

•      Offline storage by maintaining a register. That means the data is hand written into a book

•  Other way is that the data get’s stored in computer folder. In a Centralized Database (i.e. there is a server where the data get’s stored)
  

Now the issue related to these methods is that:

• The register book might get damaged by natural cause or wrath of time

• The centralised data could get corrupted

• The officer or any other person might change the data manually without authentication or permission

• As the database is centralized, it can be easily hacked

All this means that being a user of system, all we can do is trust the government as well as the system.

How would Blockchain help?

1. Blockchain is a decentralized distributed system.

   1. This means that there is no one controlling authority as well as every computer in the node has a copy of data present in the block (database).

   2. Deleting a data or altering it would need the person to alter the data from millions of computers present on the node.

   3. Even hacking all those devices won’t help as the hacker needs “Proof of work” in order to do any type of change.

   4. Plus all this needs to be done on each and every device present in the node

2. It is protected by Hashing Algorithm

   1. Described in my previous blog, each block of the ledger has a hash code of itself as well as a hash value of previous block

   2. Due to avalanche effect, altering the data even by a bit would generate a completely new hash

   3. That newly generated hash won’t match up with the hash stored in previous block. Hence denoting that the block was tempered by someone

Hence, this way the ledger is immutable and the data is secure in blockchain