1. Substrate An open source framework for building blockchains
Shawn Tabrizi Software developer @ Parity Technologies Ltd.
Hi, my name is Shawn Tabrizi
today I will be talking to you about Substrate
a really cool project we are working on at Parity Technologies

2. GitHub / Twitter: @shawntabrizi
Software
Background:
Identity and Authentication
Cloud Infrastructure
Ethereum DApp Development
Substrate Development
First, a little about myself.
As I said, my name is Shawn and for the last 4 years I was working at Microsoft working on Cloud Identity and infrastructure.
During my time there, I learned about and started developing on Ethereum. More recently I have been developing on top of Substrate, which is one of the things I will be talking to you about today.
GitHub /

3. We will talk about: Substrate Rust Wasm Blockchain Upgrades
Building on Substrate
To give you an overview…
Today we will be talking about:
Substrate
Rust
Wasm
Blockchain Upgrades
a live demo
and how you can start Building on Substrate

4. A quick review of blockchains
Blockchain nodes need:
Database
P2P Network
Consensus Algorithm
Transaction Handling
State Transition Function (Runtime)
Block 41
Block 42
Block 43
HEADER
HEADER
HEADER
BODY
BODY
BODY
Blockchain is a log of state transitions
All transitions are bundled in blocks
each block references its parent
The specific details each chain are defined by that blockchain
To run a blockchain node, you need…
A database to store the current state
P2P network for nodes to talk
Consensus algorithm for nodes to come to an agreement
Transaction handling to queue and manage messages
State Transition function which is the main logic of the blockchain

5. How does blockchain development happen today?
Most projects do not have the ability to get a whole team of developers
to build the entire blockchain stack
Instead, they fork existing projects
and make modifications of the parts they want to customize
Most often the underlying blockchain logic, which we call the runtime

6. Parity has a lot of blockchain building experience...
github.com/paritytech/
parity-ethereum
github.com/paritytech/
parity-bitcoin
github.com/paritytech/
polkadot
Parity Ethereum
Parity is most known for our Ethereum Client
It comprises about 30% of the main network
Used by enterprises such as Google and Microsoft
Parity Bitcoin
A robust and modular client for miners
Bitcoin and the Bitcoin Cash network
Polkadot
A next generation, multi-chain protocol
At the center is a relay chain
It was through the development of the polkadot relay chain that we realized:
“Hey, we have already written these pieces before…
What if we could generalize the concepts,
and build a framework so we don’t have to start from scratch each time…”

7. From Polkadot, came Substrate.
And so, from Polkadot, came Substrate...

8. What is Substrate?
Substrate is an open source, modular, and extensible framework for building blockchains.
Substrate is an open source, modular, and extensible framework for building blockchains…
It is currently listed under the GPL license, but we will be switching to Apache 2 soon

9. What is Substrate? Substrate Provides: Database Layer Networking Layer
Consensus Engine
Transaction Queue
Library of Runtime Modules
Each of which can be customized and extended.
Substrate provides you with everything you need to run a blockchain out of the box.
But if you need to, you can choose to customize all these components for your specific needs

10. What else do you get with Substrate?
Interchain connectivity via Polkadot
Hot-swappable, pluggable consensus
Light client
Chain synchronisation
Pub/Sub WebSocket JSON-RPC
JS Libraries/Tooling
Telemetry
Forkless runtime upgrades
Through polkadot it can talk to other chains, exchange messages, tokens, etc…
You can start using substrate now, and later upgrade your chain to a new consensus algorithm
Light client support for free
Chain synchronization already built in
Publish Subscribe websocket API which we use for…
JS libraries and tooling we have already made
Built in telemetry
And a method to upgrade your chain logic without causing a fork

11. Built into both Wasm & native
RUNTIME
Written in Rust
Built into both Wasm & native
governance
dao
staking
slashing
csprng
parachains
permissions
smart contracts
WEBASSEMBLY
Written in Rust
Built into native
CONSENSUS
libp2p
So let’s look at the Substrate architecture
You have the Wasm Interpreter, Consensus and Networking layers
Written in Rust, and compiled to your native executable
Then you have a runtime layer which is also written in Rust,
But is compiled to both WASM and the native executable
Building components of Substrate

12. Substrate is written in Rust.
Rust is a new systems programming language started by mozilla and used in firefox
In fact, all of our clients:
Parity-ethereum
Parity-bitcoin
And even our upcoming clients for Polkadot and ZCash
are written in Rust.

13. Why Rust? Parity is a Rust team as much as it is a blockchain team
Rust is Safe
Rust is Fast
Rust is Lightweight
Rust is Idiomatic
Rust is Fun
Rust ensures that our programs are free from:
undefined behavior
data races
any memory safety issues.
Rust is crazy fast
Has zero runtime overhead
It is easy to read
And once you get the hang of it, can be fun to write

14. Why WebAssembly? Wasm is a platform independent executable format
Wasm is Compact
Wasm is Sandboxable
Wasm is Deterministic
Wasm is Near Native Speed
Wasm is Well Supported
Was was made to be:
as close to native machine code as possible
while still being platform independent.
Wasm is:
Designed to be compact so it can easily be transferred over the web
Sandboxed to protect users from buggy or malicious code
Determinism is obviously incredibly important for a runtime and reaching consensus
Close to machine code means close to native speed
Well supported by the community, all major browsers and companies

15. Rust for Wasm ...and these two technologies work really well together!
Rust compiles directly to Wasm
Native and Wasm binaries use the same runtime codebase
Parity has built a Wasm interpreter in Rust
Small .wasm files
Rust compiles directly to wasm
Which means that we can create the native and wasm binaries using a single codebase
To support projects which use WASM, we built a Wasm Interpreter for Rust called wasmi
And, because rust has no runtime, you do not have any extra bloat in your wasm binaries
Like a garbage collector

16. Built into both Wasm & native
RUNTIME
Written in Rust
Built into both Wasm & native
governance
dao
staking
slashing
csprng
parachains
permissions
Wasm stored on-chain
smart contracts
WEBASSEMBLY
Written in Rust
Built into native
CONSENSUS
libp2p
And because the WASM runtime we build is so small
we can actually store it on chain
And this is where the magic happens
Building components of Substrate

17. Forked Blockchain Upgrades
OLD LOGIC
OLD LOGIC
OLD LOGIC
OLD LOGIC
OLD LOGIC
OLD LOGIC
Only a subset of nodes upgrade
NEW LOGIC
NEW LOGIC
NEW LOGIC
NEW LOGIC
Traditional blockchain platforms would need to fork to do a logic upgrade
When new binaries are released with updated logic
Nodes would need to upgrade
Not all nodes actually upgrade right away, so you get a fork
For example, Ethereum’s Constantinople upgrade
Which requires tons of coordination, not really suitable for distributed systems

18. Forkless Runtime Upgrades
Wasm runtime
(from chain) ✘
WebAssembly Interpreter
Merklised
storage
database
Native runtime is same version as on-chain runtime?
Native client environment
ENTRY APIs ✔
Native runtime
(from client)
With Substrate, we can do something different
Because our runtime is stored on chain
We can actually compare the native binaries running our node
To the “latest” wasm runtime stored on chain
If they are the same, then we run the native code because it is faster
If it is different, we will run the wasm binaries within the wasm interpreter
Ensuring that all nodes stay in sync

19. Context: The CryptoKitties Craze
Cats almost broke the internet… again.
Non-fungible tokens are unique
CryptoKitties represents these tokens as digital pets
Peak popularity in December 2017
Almost “broke Ethereum”
What if Substrate was available…?
I want to do a demo, but first I want to give a little context
Similar to blockchains managing your token balance
blockchains can allow you to track and manage unique assets (NFT)
CryptoKitties is a dApp which allowed users to create, own, and trade unique tokens represented as Kitties
In December of 2017, the game was so popular that
it accounted for up to 25% of Ethereum traffic at peak times
This caused huge delays to transactions
and caused significant increases to the cost of transactions
As a dApp developer, the only option at that time was to build on Ethereum
What if Substrate was available at that time…?

20. Let’s do an upgrade... Live Demo
Run the Substratekitties chain without breeding
Show the Substrate UI
Explain kitties a little
Upgrade the chain in the substrate UI
Refresh the page
Show breeding
Breed a cat, explain

21. Substrate Collectables Workshop
Run a local Substrate node
Learn about runtime development and best practices
Build a working chain with UI
Minimal Rust Experience
Kitty by David Revoy
tiny.cc/paritySubstrateWorkshop

22. So in summary…
We talked about:
Substrate as an open source framework for building custom blockchains
Rust and Wasm as ideal technologies used to build this framework
Forkless Runtime Upgrades which allows your network to stay in sync
Encouraging you to make good upgrades to your chain without the social ramifications
The Substrate Collectables Workshop which can enable you to start building on Substrate TODAY

23. We’re hiring! parity.io/jobs
If you found anything I talked about interesting
You should check out our job listings at...

24. Parity events and updates
parity.io/newsletter
You can keep up to date about events or updates
By subscribing to our newsletter

25. shawn@parity.io @shawntabrizi
Questions?
@shawntabrizi