Update 2021-06-09:

• Project updated to use dfx 0.7.1 and js libs v0.9.0
• 🥳 Demo is live on IC mainnet! Try it here 👉 https://rivyl-6aaaa-aaaaf-qaapq-cai.raw.ic0.app/

The Internet Computer by Dfinity Foundation promises to create "a limitless environment for smart contracts that run at web speed, serve web, scale, and reduce compute costs by a million times or more".

Ethereum apps that wants to deliver above and beyond of what is possible on chain often resorts to using regular centralised server solutions. Could off chain functionality instead run on the IC to create a mixed breed of Ethereum/IC apps - truly distributed, serverless and unstoppable?

The purpose with The Wall is to try out and showcase a few concepts with regards to building these crossover Ethereum/IC apps. A proof of concept, a demo and possibly a template to use as a starting point for more advanced apps.

Key concepts

1. Authentication: Can public key cryptography already used by Ethereum be used to login to the IC?
2. Link eth adresses to IC identities: If owners of eth adresses can easily prove ownership and link that verification with IC identities, that would open up many interesting app possibilites - voting, membership and other various DAO use cases.

The Wall

The functionality of the app is super simple. Connect Metamask wallet, sign a login message, select a username. Then you can post messages to the wall.

Login details:

1. User signs a login message using Metamask. The login includes a hashed secret that for the purpose of this demo is set by the app. To add an extra layer of security this secret (password) coud instead be chosen by the user.
2. App generates the Ed25519KeyIdentity needed to authenticate with IC based on the signature hash.
3. Message hash and signature is sent to IC where the eth address used to sign the message is recovered and linked to the IC identity.

That's it! Now, the app can interact securely with IC, and IC has verified knowledge of which eth address the user controls.

Run locally

1. Prerequisites

Make sure you have the following installed:

node
npm
git

2. Install DFINITY Canister SDK

Download and install the DFINITY Canister SDK package by running the following command:

DFX_VERSION=0.7.1 sh -ci "$(curl -fsSL https://sdk.dfinity.org/install.sh)"

3. Install Rust / Cargo

The app backend is written in Rust. The commands below install Rust, the package manager Cargo, etc.

curl https://sh.rustup.rs -sSf | sh
rustup update
rustup target add wasm32-unknown-unknown
sudo apt-get -y install cmake
cargo install ic-cdk-optimizer --root target
export PATH="./target/bin:$PATH"

4. Clone this repo, install dependencies

git clone https://github.com/kristoferlund/ic-wall.git
npm install

5. Run!

Terminal 1

Start Internet Computer

dfx start

Terminal 2

Alt 1. Development mode with hot reload

• Deploy backend canisters
• Run next.js frontend in dev mode

dfx deploy wall
dfx deploy profile
npm run dev

Access on http://localhost:3000

Alt 2. Production mode

• Export static production version of next.js frontend
• Deploy all canisters

dfx deploy wall
dfx deploy profile
npm run export
dfx deploy ui

Access on http://localhost:8000

In case you receive "Could not find Canister ID from Request":

• Get UI canister ID

dfx canister id ui

Access on http://localhost:8000/?canisterId={id received in previous step}

Author

Kristofer Lund, [email protected]

Telegram: @kristoferkristofer

Contributing

Yes, please! Raise an issue or post a pull request.

TODO

[ ] Error handling all over!

[ ] Refactor canisters - better structure, naming etc.

License

MIT