What is Blockchain?
This is what a traditional record book looks like. The page’s image is self explanatory. While it is easy to understand what this bunch of white turned yellow pages does, it is also easy to be tampered with. This is what an “old school” organization’s file look like. Let’s consider this, data on the first page will be numbered from suppose 1–10, then data on the next page will be numbered from 10–20 which forms like a chain of pages where one page is linked with the next one and so on. Now if someone tears lets say 3rd page, we would know that the record book is being tampered with but we cant recover the missing data.
Now considering the fact that many organizations don’t use this kind of record system and they instead hand over this job of maintaining data to 3rd party have which claims to have a well built robust system and charges heavily for their service. But is it really tamper proof?
Doesn’t look like.
What if I say Blockchain can make this system tamper proof?
What exactly is “Blockchain”?
Blockchain is nothing but chain of blocks.
What do you mean by “blocks”?
Blocks contain data. It can be related with a page of physical register book where data or transactions (it not necessarily has to be related with money, for example, one person came inside a building at 10 AM, that makes it a transaction, he left at 2 PM, another transaction) are recorded. One block is linked with another one and that block with the next one. But there is a twist. The blocks are linked with very next one with a unique “hash”.
Wait, what is “hash”?
Hash is a combination of random numbers and alphabets. it looks like this
“2d77452ccfecb67c36a57e292cb9dd351c15764da565e4eff62137e1f05ee542”
It is generated when you pass any data to hash function(consider this as a grass cutting machine whose sole purpose is to give you small pieces of grass irrespective of height of grass).
A very unique thing about hash function is that it gives a specific length hash. “No matter how big or small data you give to hash function, length of output hash will remain constant”
length of hash of “A” is same as of “Algorithm”
Another unique thing about hash function is, even if there is a small change in data, whole hash will change. Look at this
A data of “Mr Suresh came inside the building at 10 AM” gave following hash-
“78a46dcd1277aa11057f5acab639f934c588cc53e16d5ae2ea8617b619e0f082”
Now, suppose I change time from AM to 10:01 AM. Look at the hash generated
A total different hash after a slight change in data.
Now that we have understood what hash is, we will see how blocks are connected using hash.
Hash of block number 1 is generated and fed along with 2nd block’s hash to hash function to generate a new hash. That newly generated hash is fed to hash function along with 3rd block’s hash in order to generate a new hash again. This is how 1st block is linked with 3rd block. So, if I changed data in first block, hashes of subsequent blocks will change.
Since first page is linked with last page, tampering cant be really brought into practice.
If you failed to understand anything, kindly do your own research and avoid asking question in comment section.
Just kidding, feel free to ask anything related to topic (: