cChannel-substrate

• Overview
• Core Concepts
• Release Features
• Run Celer local testnet in Docker
• Buidling and Testing celer-pay runtime module from source

Overview

CelerPay is a generalized payment network that supports efficient off-chain token transfer with the capbability to resolve arbitrary conditional dependency on on-chain verifiable states. This repo implements the CelerPay runtime module with substrate. It includes a collection of runtime module acting as the binding of core CelerPay abstractions and supporting modules. CeleryPay runtime module only specify the interaction logic of two peers. A network of payment channels can be built using these single-hop primitives and protocols.

To learn more about Celer state channel network, please refer to the CelerCore technical documentation. More specifically, this page gives a detailed description of our smart contract design, structure, and API flows.

Celer state channel network is composed of Celer-pay Onchain runtime module and Celer-pay Offchain protocol. This repository is Celer-pay Onchain runtime module. Celer-pay Offchain protocol is not implemented yet.

WARNING: This is a proof-of-concept prototype. This implementation is NOT ready for production use.

Core Concepts

• Peers: channel participants (only supports two-peer channel for now).
• Simplex Channel: a single-direction payment channel from one peer to the other peer.
• Duplex Channel: a bidirectional payment channel between peers including two independent simplex channels.
• Simplex State: a piece of data describing the state of a simplex channel.
• Signed Simplex State: Simplex State signed by channel participants, which serves as a bridge data structure between on-chain runtime module and off-chain communication protocols.
• Condition: data structure representing the basic unit of conditional dependency.
• Transfer Function: a higher-level abstraction of generalized state dependencies on a group of conditions.
• Conditional Payment: data structure representing a physical payment from payment source to payment destination.
• Payment Source: the address sends out a payment, namely the source of this payment route.
• Payment Destination: the address receives a payment, namely the destination of this payment route.
• Vouched Conditional Payment Result: the result of a conditional payment agreed by the payment source and payment destination.
• PayRegistry: a global registry which updates and records all payment results.
• PayIdList: data structure including a list of payment ids and a hash pointer to next PayIdList, which is used in Batch Multi-Payment Clearing.
• Pool: Pool enables the single-transaction channel opening feature of CelerPay

Release Features

• Native token Support: users can specify polkadot native token to open an Substrate-based channel.
• Generalized State Channel: resolves conditional state dependency by relying on dependent virtual channels.
• Fully Duplex Channel: supports two independent simplex (single-direction) channels in a duplex channel, which makes off-chain communications much simpler and more efficient.
• Boolean Condition Interface: defines the condition that returns boolean value.
• Boolean AND Resolution Logic: resolves a group of conditions based on boolean AND logic.
• Boolean OR Resolution Logic: resolves a group of conditions based on boolean OR logic.
• Numeric Condition Interface: defines the condition that returns numeric value.
• Numeric ADD Resolution Logic: resolves a group of conditions based on numeric ADD logic.
• Numeric MAX Resolution Logic: resolves a group of conditions based on numeric MAX logic.
• Numeric MIN Resolution Logic: resolves a group of conditions based on numeric MIN logic.
• Single-transaction Channel Opening: opens channel with a single on-chain transaction through funds approval for native token.
• Dynamic Withdraw: withdraws fund before channel finalized as long as no peers disagree during challenge period.
• Cooperative Dynamic Withdraw: skips challenge period and withdraws fund before channel finalized when both peers reach an agreement.
• Lightweight cooperative on-chain checkpoint: support snapshotting transfer map of co-signed states on-chain.
• Batch Multi-Channel Settlements: intends to settle multiple channels in one batch with a single on-chain transaction.
• Batch Multi-Payment Clearing: clears N payments in one batch with a single on-chain transaction using PayIdList, which only requires O(1) on-chain storage and O(n/N) on-chain verifications to clear n payments.
• Cooperative Settle: skips challenge period and settles a channel when both peers reach an agreement.

Run Celer local testnet in Docker

docker run -p 9944:9944 -p 9615:9615 thashimoto19980924/celer-network:0.8.8

Building and Testing celer-pay runtime module from source

1. Fast Installation

Mac OS, Arch, or a Debian-based OS like Ubuntu

curl https://getsubstrate.io -sSf | bash -s -- --fast

Debian

sudo apt install -y cmake pkg-config libssl-dev git gcc build-essential clang libclang-dev

MacOS

brew install openssl cmake llvm

2. Rust Developer Environment

curl https://sh.rustup.rs -sSf | sh

rustup default stable

3. Wasm Compilation

rustup install nightly
rustup target add wasm32-unknown-unknown --toolchain nightly
rustup default stable

4. Install celer-pay runtime module

git clone git@github.com:celer-network/cChannel-substrate.git

5. Go to cChannel-substrate's root directory

6. Build celer-pay runtime moodule

cd ./pallets/celer-pay
cargo build --release

7. Test celer-pay runtime module

cargo test -p celer-pay-module

lib.rs:

RPC interface for the transaction payment module.