Blockchain is a network where there is no single server or managing company. Instead, there are thousands of independent participants (nodes), each with their own copy of the data.
How can a unified decision be made and transactions confirmed in such a system?
The answer is consensus.
It is a mechanism that allows network participants to agree on a single, truthful version of the data – without central authority.
Why is consensus needed?
-To confirm transactions – all participants must agree that they are correct
-To create new blocks – and avoid duplication or forgery
-To prevent attacks (for example, double spending)
How is consensus achieved?
Through special algorithms (which we will discuss tomorrow). They determine:
-Who can add a new block
-How to verify its authenticity
-What to do if different versions of the blockchain appear
Without consensus, the blockchain would simply be a collection of disparate databases.
And with it, it becomes a reliable, secure, and transparent system.