Mining and Consensuses in Blockchain
In the previous blog we got to know what a Blockchain is, and how you can we create a Java based Blockchain which can not be tampered (Integrity).
Blockchain has couple of more design principles other than Integrity : Decentralized, Consensuses, Public Ledger etc. Before we jump to Mining it is important to understand these concepts first.
Public Ledger
Assume that different participants are adding transactions and blocks to a Blockchain. That means there has to be a central Blockchain that is accessible to all, since all participants needs to add block to the existing Blockchain, This means there has to be a master participants governing and storing the Blockchain. But this is against the principle of Blockchain (Decentralized). There is no master participant in the network. To solve the above issue, each participant keeps a copy of the Blockchain with itself. Once a block is added, it is distributed across the network and all participants update their Blockchain. This concept is called Public Ledger. A ledger (list of transactions) which is public.
But this causes another problem in the network.
Lets assume that 2 participants are trying to add a block, simultaneously to a Blockchain. Only one can be allowed to do so and the other has to be discarded since the previous hash in that block will be invalid.
