What is BLOCK CHAIN ??

 Block Chain is the base technology behind crypto currency and this technology only makes it impossible for crypto currency not to be tempered or modify or cheated. In other words its an information organising and storing system in which bunch of information are connected with different blocks (here blocks refer to a piece of information) ever block has generally 3-parts.

1. Hash code (Unique Identification / encrypted code)

2.Information / Data

3. Hash Code of  preceding block.

As this block chains are highly interconnected it would be impossible / very very difficult to modify or change block as a single change will lead to change in the complete block chain. Block chains are also very de centralized there is absolutely zero server down time (ie. no error 404 !! ), this happens as every block chains are saved on all computers/devices connected with block chains as nodes. And it would be not possible to switch off all nodes at same time.

Is there any threat to information saved in localized nodes ?

Actually no,  according to me there is no threat to our information stored in nodes as all our information saved is secured by two specially encrypted keys 1. Public Key 2. Private Key

The combination of these both keys save and make this information visible only to actual/original recipient of information. You can understand  this by example of email id (public key) and email password (private key).

Future applications of  this technology ..

This technology can be used by educational institutions to store and record the student data and result in such a way that it cannot be changed by anyone after publishing it , not even by the educational institutions !! And the added advantage is that we cannot loose all information due to central server failure as there are many copies of  block chains in every node.

One more technological application could be used to revolutionize the voting method , which could make our votes self verified and non editable after publishing vote. And one more advantage of this tech in voting is that your voting credentials / identity would always be encrypted / hidden / un-identifiable. And the biggest perk of this is there is zero dependence of vote counting on central election commission (eg Election Commission of India in India).