Polkadot was founded by Dr.Gavin wood and co-founders Peter Czaban and Robert Habermeier in 2016. Polkadot is a Layer-0 , scalable (limitations of the blockchain for the processing of multiple transactions) heterogeneous multi chain Network with shared security. Polkadot provides the system (relay chains) , in which many layer 1 protocols like Ethereum, Bitcoin, Litecoin , Avalanche, BSC(binance smart chain) etc can communicate with each other by parallelised chains or popularly known as Parachains which can be bought through an auction, in which a user can vote or select their favorite Parachain / Parachains by locking some Dot with the selected ones for a fixed period of time usually 94~92 weeks. If the selected Project didn't win the auction the tokens will be returned to their respective wallets.

Lets learn about some terms before we dive in:

Consensus Mechanism:

A consensus algorithm is a procedure through which all the peers of the blockchain network reach a nesssary agreement about the present state of the distributed ledger(database). Polkadot uses Proof of stake (PoS) consensus.

Validators:

Validators help to seal new blocks on Polkadot network. They are like bankers who approve transactions. Validators role depends on bonds depends on bonds given by nominators.

Nominators:

Nominators are stake holding parties, who contribute to security bond of validator. They just act like miners in Proof of work consensus. They don't have any extra role.

Collators:

They are parties who help validators in producing valid parachain blocks.They they retain all necessary information to be able to author new blocks and execute transactions in much the same way as miners do on current Proof of work blockchains like Bitcoin, Litecoin.

FISHERMEN:

• Fishermen are not directly related to the process of validating blocks. Rather they are like cops in blockchain who report illegal blocks or transactions. They recieve  one time reward when reporting a illicit transaction.To prevent re-rewarding or the compromise and illicit use of   session’s secret key, the base reward for providing a single validator’s illegally signed message is minimal. This reward increases  as more  illegal signatures from other validators are provided implying a genuine attack.

Honestly I also didn't understand anything from this picture 😂😂.

BFT Algorithm 

Did you guys know Byzantine fault-
tolerant algorithm? This is based on the Conquest of Istanbul which  was the capture of the capital of the Byzantine Empire by the Ottoman Empire. The city fell on the end of a 53-day siege which. Now here's the problem, let's say there are 50 commanders and some lituenents laying the seige. Now the King only wants victory, but there may be traitors in the army . Now these generals depend on messengers to rely messages between them who may tell so soldiers to attack, stay or leave which they may not reach consensus due to the disagreement. If 2/3rds are good , then they might win. This is a very complex problem. But we know that the problem was solved when the city fell to the seige.

Use of BFT Algorithm In Polkadot:

It's used in the relay chain to achieve consensus over a set of mutually agreed blocks , it's inspired by Tendermint (its a software used to securely and constantly replicate an application on many devices) and Honey badger BFT.

Parachains and Collators:

Each parachain gets similar security affordances to the relay-chain: the parachains’ headers ar sealed inside the relay-chain block making certain no shake-up, or “double-spending”, is feasible following confirmation. this is often the same security guarantee to it offered by Bitcoin’s side-chains and merge-mining. Polkadot, however, additionally provides robust guarantees that the parachains’ state transitions ar valid. This happens through the set of validators being cryptographically randomly divided into sets; one subset per parachain, the subsets probably differing per block. This setup usually implies that parachains’ block times are a minimum of as long as that of the relay-chain. 

Interchain Communication:  

Interchain communication is one of the important part of polkadot . Since parachains have some sort of communication channel between them, we consider Polkadot a scalable multi-chain. In the case of Polkadot, the communication is as simple as can be: transactions executing in a parachain are able to effect the dispatch of a transaction into a second parachain or,  the relay-chain. Like external transactions on production blockchains , they are fully asynchronous and there is no  ability for them to return any kind of information back to its origin.

Is Polkadot designed to replace blockchains?

No, rather than replacing blockchains polkadot is designed to provide communication between blockchains new , old or upcoming ones if they desire. Who doesn't desire to reach to greater masses?

DOT :

Its the token of the polkadot ecosystem. They are mainly used in staking and Validation processes as Polkadot is a PoS consensus.The purpose of Dot tokens is to be a direct representation of stake in the Polkadot network.

 Outro:

We can see that Polkadot has some pretty solid fundamentals. It will be very useful in connecting different blockchains. There are currently 100 parachains, we'll see what happens when they are exhausted, will they increase the number or a new blockchain will emerge which will connect all of the blockchains seamlessly without any limitations? Only time can tell us.

Feel free to ask any questions and comment if I have missed anything.

Tips would be generous. Wishing you all a prosperous new year.