An article to understand the Polkadot consensus

This series will be a discussion about security and consensus in Polkadot. In Part 1, we will define some terms before diving into the details of how Polkadot creates and secures blocks.

Consensus algorithms help computer networks behave like a single computer. In practice, this means that almost every computer in the network must agree to some initial state and then agree to a deterministic log of operations to the initial state in order for them to reach a consistent final state.

While blockchain brings some interesting tools to the field, the existence of this coordination problem is not new. The problem has its origins in aerospace, where computers on satellites or high-altitude aircraft can behave arbitrary due to the desolation of high altitudes. Imagine you have a network of flight computers and you want to know where the plane is going. It doesn't matter which computer on the network you ask, because you should get the same response.

What does the above have to do with blockchain? We want a network of computers to agree on certain values. These values ​​can be account balances, voting results, or the execution of smart contracts.

In fact, some pre-existing consensus algorithms are very similar to blockchains. In a 2001 lecture, MIT professor Barbara Liskov talked about batching transactions to improve the performance of Practical Byzantine Fault Tolerance (PBFT), before Bitcoin existed.

"Imagine a very busy newbie, being hit with one request after another; it doesn't actually start the protocol for each request. Instead, it collects a batch of requests and targets one of them A group request enforces an agreement. ... It is not necessary for an individual to send a reply to each client. Sending a summary of the responses to an individual in the group is feasible, as it is sufficient for the client to know whether it has the same reply."

secondary title

Breaking Blockchain Consensus

3. What if someone breaks the rules?

Because many blockchain consensus protocols unite them, it is important to make these distinctions early on. For example, the proof mechanism of workload proof is to select the appropriate recorder of the block; the longest chain determines which chain is the final chain; the cost of making proof is the punishment for violating the rules. In the Polkadot protocol, all of these questions are answered in isolation.

Non-blockchain systems can still answer these questions. For example, assuming all computers are running the same software, this is a good thing in most cases. So if Boeing builds an airplane, it's safe to assume they programmed all the computers on the airplane accordingly.

But in the public network we cannot make such an assumption. Blockchains allow us to use economics to simplify some network assumptions. All consensus systems have a notion of "good" and "bad" behavior. The inherent economic properties of the blockchain allow us to reward good behavior or punish bad behavior. Proof-of-stake networks use economics as a direct means of ensuring consensus.

Security in a blockchain system is a measure of how difficult it is to break consensus. Security is the hard part of controlling permissions in order to prove authoritative. In Proof of Work, security is the necessary cost of acquiring and running enough hash power to create a chain longer than the network. In proof of stake, security is the value of stake and risk.

Edit / Dolly

Original link:https://polkadot.network/

Edit / Dolly