Example Client-Server Webapp Using Sodot MPC SDK

This is a minimal example project of both an Express.js server and a simple website that leverages Sodot MPC SDK for creating distributed private keys for both ECDSA (on secp256k1) and Ed25519 signature algorithms, as well as threshold signing using MPC.
More information on Sodot MPC SDK can be found in Sodot's technical docs.

Project Structure

There are 2 npm projects in this repo.
The server at the root directory and a web client code in the web-client directory.

• All server code is in javascipt and found in src/server.js
• The client code is in Typescript found in web-client/src/index.ts
  • The web-client project is written in Typescript just to showcase how using Typescript works with the SDK.
  • The web-client utilizes Karma in order to run the web app itself in a headless browser to make it easier to run the full client-server flow from within the root Node project.
    • Any details associated with Karma are not particularly interesting for the project.
  • Due to how Karma works, the actual client-side code that calls the logic in web-client/src/index.ts is in web-client/spec/index.spec.js.

Project Flow

First, the server is run and exposes a REST API with endpoints for keygen, sign, and refresh.
Then, the web-client is run in a headless browser.
The web-client does the following:

• A keygen flow with the server, resulting in the client and server each holding a key share for a 2-of-2 controlled public key.
• A signing flow, signing a message together with the server, here key derivation is utilized to showcase that many different public keys can be used based on 1 underlying keygen session.
• A refresh flow, this results in new (fresh) key shares for both the client and the server for the same public key (and all key derivation of the master public key).
• Finally another signing flow, to showcase how the new key shares generate valid signatures for the same public key.

Running the Project

Setup

First, you will need an API_KEY and an NPM_TOKEN. This can be requested from the Sodot team.
Add your NPM_TOKEN to your environment variables:

export NPM_TOKEN="YOUR_NPM_TOKEN"

Create a file in the root directory of this repo named .env, in it add the following line:

API_KEY=<YOUR_API_KEY>

Now, install all necessary packages for the server and the web-client.

npm i
cd web-client && npm i

Running the Client-Server Flow

From the root directory of the project run:

node src/server.js