[Blah-Chain : Talk19. A Hash]

Last time when we talked about the elements of a block, we have learned that block header includes hash, nonce, timestamp, etc. So what are they? Let’s get to know about “Hash” today.

The hash is used to create the characteristic value for each block. In the blockchain system, all data is turned into the hash value.

The hash is added to each data, so no matter how big the data is, the characteristic value can represent the document.

It means that with hash, it’s simple to figure out if the data is forged no matter who has the original document.

Then how to decide the hash?

Nodes find the hash value by calculating. Among the answers they find, the most spread one is usually decided as a hash value.

In the blockchain system, the hash is used to show the state of the blockchain. The hash includes the hash of the previous block as well. So when a new block is created, all the previous transactions will be added.