Perun CKB Contracts

Perun CKB contracts

This repository contains the smart contracts that implement Perun payment channels on Nervos CKB, enabling secure and efficient off-chain transactions backed by CKB’s UTXO architecture.

The design follows the same encoding and verification semantics used in the Perun Ethereum contract.
By applying an Ethereum-style binary encoding format for channel identification, and signed updates, the CKB implementation can validate the same off-chain messages recognized by Ethereum. This ensures:

• a compatible state representation across chains
• cross-chain verifiability of signed updates
• interoperability with Ethereum-based Perun backends
• support for multi-chain Perun channels and swaps

This shared data model allows Perun channels on CKB combined with Perun channels on Ethereum.

Scripts Overview

1. perun-channel-lockscript

Controls access rights to the live Perun channel cell.
Only channel participants can consume or update the channel.

2. perun-channel-typescript

Implements the on-chain state machine for Perun channels.
It validates channel state transitions and enforces correct dispute handling.
Functionally similar to a stateful NFT script with Perun-specific logic.

3. perun-funds-lockscript

Manages the channel’s locked assets (CKB or SUDT).
Ensures that only the channel’s participants can withdraw or move funds.

Prerequisites

Update the rustc version to 1.85.0 and install the following:

sudo apt install gcc-riscv64-unknown-elf binutils-riscv64-unknown-elf \
libc6-dev-riscv64-cross libc6-riscv64-cross linux-libc-dev-riscv64-cross

wget https://apt.llvm.org/llvm.sh && chmod +x llvm.sh && sudo ./llvm.sh 18 && rm llvm.sh

cargo install cargo-generate

Add the target:

rustup target add riscv64imac-unknown-none-elf

Build and Test

Build contracts:

chmod +x ./setup_env.sh

make prepare

source ./setup_env.sh build && make build

Run tests:

source ./setup_env.sh test && make test

or run them using the IDE

perun-common

Additionally, to the available contracts we extracted common functionality into its own perun-common crate which gives some additional helpers and convenience functions when interacting with types used in Perun contracts.

Problems

1. Missing file gnu/stubs-lp64.h

A common issue when compiling for RISC-V is the missing file: gnu/stubs-lp64.h

If the necessary packages are already installed, the file /usr/riscv64-linux-gnu/include/gnu/stubs-lp64d.h should exist instead. This is due to the toolchain using the lp64d ABI (which includes double-precision floating point support) rather than plain lp64.

To resolve this, simply create a symbolic link:

sudo ln -s /usr/riscv64-linux-gnu/include/gnu/stubs-lp64d.h /usr/riscv64-linux-gnu/include/gnu/stubs-lp64.h

Then try compiling again.