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Polkadot

  • date: 2023-02-04
  • last updated: 2023-02-04

Overview

Note: The majority of this research was done in early 2019 and has been updated recently with some notes on consenus and signing. In 2021 John built and deployed a Parachain called Eave Network codebase is here. The parachain was deployed to the Rococo Testnet. John self funded this initiative, but failed to raise seed funding, due to this and other priorities this project was never fully developed and deployed on Kusama or Polkadot. Polkadot is one of John's favourite development frameworks and he is extremely grateful for Gavin Wood and Tomasz Drwięga who he was fortunate enough to collaborate with briefly on the Parity Ethereum Client in early 2016 as he began his blockchain journey.

Polkadot substrate is a chain layer which allows pluggable consensus, definition of storage through the seperation of "extrinsics" and abstracts the runtime design allowing for blockchain providers to decide which runtime best suits there application needs. It also has been built with light client protocol in mind with a number of storage and pruning options giving the ability to clearly seperated different actors requirements for infrastructure (e.g. participants can run a light client on a mobile device and validators can run full nodes with gauranteed performance and uptime). On top of this Polkadot sits as a relay chain (built on Substrate) which allows private chains to share infrastucture such as validators.

Consensus Mechanism

Following is an excerpt from Polkadot learn consensus

Nominated Proof of Stake

In traditional PoS systems, block production participation is dependent on token holdings as opposed to computational power. While PoS developers usually have a proponent for equitable participation in a decentralized manner, most projects end up proposing some level of centralized operation, where the number of validators with full participation rights is limited. These validators are often seen to be the most wealthy, and, as a result, influence the PoS network as they are the most staked. Usually, the number of candidates to maintain the network with the necessary knowledge (and equipment) is limited; this can directly increase operational costs as well. Systems with a large number of validators tend to form pools to decrease the variance of their revenue and profit from economies of scale. These pools are often off-chain.

A way to alleviate this is to implement pool formation on-chain and allow token holders to vote with their stake for validators to represent them.

Polkadot uses NPoS (Nominated Proof-of-Stake) as its mechanism for selecting the validator set. It is designed with the roles of validators and nominators, to maximize chain security. Actors who are interested in maintaining the network can run a validator node.

Validators assume the role of producing new blocks in BABE, validating parachain blocks, and guaranteeing finality. Nominators can choose to back select validators with their stake. Nominators can approve candidates that they trust and back them with their tokens.

References

Consensus Signing
  • Sr25519 Documentation: Polkadots sr25519 Documentation. The implementation of Schnorr signatures that is used in Polkadot and implements the Schnorrkel protocols over the Ristretto compression of the Curve25519 is known as sr25519.
  • Substrate sr25519 codebase: Polkadot's sr25519 code (rust).
  • ED25519
Staking Parachains
  • Subscan Explorer: Block Explorer built for Polkadot and supporting all Parachains
  • parachains: Polkadot documentation on Parachains
Additional