circles-contracts

Ethereum Smart Contracts for the Circles UBI system: A decentralised Universal Basic Income platform based on personal currencies.

Basic design

There are several components:

Token contract

This is derived from standard ERC20 implementations, with two main differences: The ability to mint UBI to the token owner, and the hubTransfer function that allows transitive transfers. Token contracts store the address of the Hub that deployed them, and can only transact transitively with tokens from the same hub. Tokens have owners, which can be an external account or any kind of contract - in our deployment, they are Gnosis Safes.

Hub contract

This is the location of system-wide variables and the trust graph. It has special permissions on all tokens that were deployed through it and have authorized it to perform transitive exchanges. All the parameters in a Hub are immutable and it has no owner.

Illustrated here are some of the main available calls:

• signup method of the Hub deploys a Circles token
• Safe or external accounts make trust connections within the hub with the trust method
• Users send transitive transactions with the hub, which has special permissions on tokens

Installation

npm i @circles/circles-contracts

Requires Node version 14.

Development

Requires Node version 14. You can change your node version to the tested version with nvm use.

Install all required dependencies via npm install.

npm test will re-build the contracts / tests and run all of the tests in the test directory.

Tests are executed with the help of Truffle and written in javascript using Mocha with the Chai assertion library.

When you run npm test a new local blockchain will be started with ganache-cli (unless you already have one running). The contracts will be deployed and the javascript tests will make transactions to this chain.

Helper functions defined in test/helpers provides functionality for more complicated tests such as: reading the event log, or checking for an EVM "revert / throw", or changing the blockstamp times.

Note that: We commit the build dir on purpose, because the rest of our stack pulls this repo in from npm and gets the abis from them.

License

GNU Affero General Public License v3.0 AGPL-3.0