However, there is one more method which is used by blockchains to secure themselves, and that’s by being distributed. Instead of using a central entity to manage the chain, Blockchains use a distributed peer-peer network, and everyone is allowed to join. When someone enters this network, he will get the full copy of the blockchain. Each computer is called a node.
Let’s see what happens when any user creates a new block. This new block is sent to all the users on the network. Each node needs to verify the block to make sure that it hasn’t been altered. After complete checking, each node adds this block to their blockchain.
All these nodes in this network create a consensus. They agree about what blocks are valid and which are not. Nodes in the network will reject blocks that are tampered with.
So, to successfully tamper with a blockchain
- You will need to tamper with all blocks on the chain
- Redo the proof-of-work for each block
- Take control of greater than 50% of the peer-to-peer network.
After doing all these, your tampered block becomes accepted by everyone else. This is next to an impossible task. Hence, Blockchains are so secure. Next, in this beginner’s Blockchain development tutorial, we will learn how a Blockchain transaction works?