## Introduction to Substrate  ---- ### Who am I? - I crouch in front of a monitor for the last 35 years - Working on decentralization and privacy since 2016 - Worked for Parity for about a year - Working for Vidákovics Attila since June - I prefer in-real-life relations to social media - Still, I do have [github](https://github.com/wigy-opensource-developer/), because of society :see_no_evil: --- ### Why do we need more than Ethereum - Single threaded, public "world computer" - Fees tie applications together into a single economical model - Proxy contracts ---- ### Proxy contracts - Implementation can be replaced - Most calls are **delegated** to an implementation - State is stored in the proxy - But who can replace the implementation? - Usually the simplest solution is used and a single person owns the private key - Multisig contract, say 3/5 - A DAO contract with voting - Both expensive in fees --- ### What is a dApp? - Just a glorified Web2 service? - Some aspects stored on-chain - Where does value come from - Is liquidity trapped on a single chain ---- ### Future is multichain - Bridges - Trusted - Multisig - DAO - almost trustless - Economic security of PoS - "One chain to rule them all"? :smile_cat: - [Avalanche](https://www.avax.network/) - [Cardano](https://cardano.org/) - [Cosmos](https://cosmos.network/) - [Polkadot](https://www.polkadot.network/) --- ### Polkadot  ---- ### Polkadot ecosystem - Relay chain (Polkadot, Kusama) - Parachains - Parathreads - Auctions for paraslots - Crowdloan ---- ### Polkadot governance - nPoS elections every 4 hours - Treasury - Proposals - [Decision](https://polkadot.subsquare.io/) [preparation](https://polkadot.polkassembly.io/opengov) - Open voting - Tracks - Technical Fellowship ---- ### Advantages over a solochain - Cross-chain messaging (XCM) - Shared untrusted bridges to other ecosystems (BTC, ETH, BNB, AVAX, ADA, ATOM) - Economic security of parachains --- ### Substrate (Polkadot SDK) - Building blocks for [creating a chain](https://invidious.flokinet.to/watch?v=0IoUZdDi5Is&t=3270) for your own application/community/DAO - Blockchain node is written in Rust - Most of the code is on-chain - Governance can replace it democratically - Compare with BCC, ETC forking events - Frontend templates in React/TS - Open-source indexers, tooling all the way --- ### Rust language - Fast, Reliable, Productive. Pick Three. - Pretty good support for cryptography - Pure functional subset for pallet writing - "Fighting with the borrow checker" - Microsoft, Cloudflare, KeyRock - Mozilla, Linux - WASM --- ### What is a pallet? - A reusable piece of storage+rpc+calls+hooks ```rust= #[frame_support::pallet] pub mod pallet { .. #[pallet::storage] pub type TotalIssuance<..> = StorageValue<..T::Balance..>; #[pallet::storage] pub type Account<..> = StorageMap<..T::AccountId, AccountData<T::Balance>..>; .. #[pallet::call(weight(..))] impl<..> Pallet<..> { #[pallet::call_index(0)] pub fn transfer_allow_death( origin: OriginFor<T>, dest: AccountIdLookupOf<T>, value: T::Balance, ) -> DispatchResult {..} } .. } ``` [balances](https://github.com/paritytech/polkadot-sdk/blob/master/substrate/frame/balances/src/lib.rs) pallet ---- ### What is a pallet? ```rust= #[derive(Encode, Decode, Clone, PartialEq, Eq, Default, RuntimeDebug, MaxEncodedLen, TypeInfo)] pub struct AccountData<Balance> { pub free: Balance, pub reserved: Balance, pub frozen: Balance, pub flags: ExtraFlags, } ``` ---- ### What is a pallet? - Has external dependencies to other pallets and the runtime configuration ```rust= #[frame_support::pallet] pub mod pallet { .. #[pallet::config(with_default)] pub trait Config<I: 'static = ()>: frame_system::Config { .. type Balance: Parameter + Member + AtLeast32BitUnsigned + Codec + Default + Copy + MaybeSerializeDeserialize + Debug + MaxEncodedLen + TypeInfo + FixedPointOperand; .. } } ``` ---- ### What is a pallet? - BTW, Polkadot deletes accounts without a meaningful balance held (Shanghai attack) ```rust= #[frame_support::pallet] pub mod pallet { .. #[pallet::config(with_default)] pub trait Config<I: 'static = ()>: frame_system::Config { .. #[pallet::constant] type ExistentialDeposit: Get<Self::Balance>; type DustRemoval: OnUnbalanced<CreditOf<Self, I>>; .. } }``` --- ### What is a runtime? - A set of pallets woven together... ```rust= construct_runtime!( pub struct Runtime { System: frame_system, Timestamp: pallet_timestamp, Aura: pallet_aura, Grandpa: pallet_grandpa, Balances: pallet_balances, TransactionPayment: pallet_transaction_payment, Sudo: pallet_sudo, } ); ``` ---- ### What is a runtime? - ...by configuring pallets ```rust= pub type Balance = u128; pub const EXISTENTIAL_DEPOSIT: u128 = 500; impl pallet_balances::Config for Runtime { .. type Balance = Balance; type ExistentialDeposit = ConstU128<EXISTENTIAL_DEPOSIT>; .. } ``` --- ### Nodes - weirdly called "clients" :man-shrugging: - p2p networking - consensus (!) - storage - WASM executor ---- ### Types of nodes - solo chain nodes - relay chain nodes - collators - parachain node + - relay chain node + - forwarding logic ---- ### Big picture ```plantuml @startuml cloud "p2p network" as p2p node client { component libp2p libp2p -> p2p component consensus component cryptography component executor database storage consensus -down-> storage consensus -down-> cryptography } node "on-chain" as chain { component runtime component "consensus pallet" as c_pallet component governance runtime *-down-> c_pallet runtime *-down-> governance } executor o-up-> "*" runtime @enduml ``` --- ### Wrap up - Multiple chains vs ecosystem - Runtime vs smart contracts - "code is law" vs communities - Web2 walled gardens vs open-source tooling --- ### Thank you! :dog: You can find me through Attila and DLabs :stuck_out_tongue: