ChainX Dev Update July 2021

3 min readJul 30, 2021

Development update time! Below you will find the summary of the work the PolkaX team has completed and get an insight into the various things they are working on. As always, if you have any questions, we are available in the ChainX Community telegram.

ChainX Smart Contract Platform

tl;dr; EVM and WASM smart contracts on ChainX

The goal of ChainX EVM is to realize the smart contract platform of ChainX, allowing developers to develop various DApps on ChainX and build the DeFi ecosystem of ChainX. The smart contract platform will first be compatible with the existing Ethereum Virtual Machine (EVM) and all applications and tools under its ecosystem. Developers can easily migrate and deploy Ethereum DApps, saving development costs. Later we will be adding WASM virtual machine compatibility, allowing developers to choose any mainstream language for the development of various DApps according to their needs.

Development progress:
1. Completed the research of the EVM implementation scheme of the substrate chain, and completed some specific implementations.
2. Completed the compatibility test of MetaMask and Remix of the Ethereum ecosystem, and the construction of related developer documents.

Taproot — BTC cross-chain solution

tl;dr; Improvement of the BTC Bridge into ChainX

The Taproot BTC cross-chain solution is a set of ChainX cross-chain solutions designed for the BTC network Taproot upgrade. The scheme will use Muisig2 to complete the off-chain Schnorr aggregation signature, which can bring strong privacy protection for signing participants while significantly reducing transaction fees. Using the new features brought by the Taproot upgrade, the solution will abandon the previous centralized hosting method and allow users to participate in the process of aggregating signatures. In the end, users and verifier nodes act as multi-signature participants, completing the multi-signature interaction of participants through a similar smart contract method, eliminating the current drawbacks of manual signatures, and achieving decentralized cross-chain to the greatest extent.

Development progress:
1. Research Taproot upgrade: bip-schnorr, bip-MAST, bip-tapscript.
2. According to the Taproot upgrade, redesign ChainX’s BTC cross-chain solution.
3. Study the secp256k1 library K256, libsecp256k1 and rust-secp256k1 based on Rust implementation, and plan to add support for Schnorr signature in light-bitcoin.
4. Research the multi-signature schemes MuSig and Musig2 based on Schnorr signature, and start to implement the multi-signature scheme Musig2 in rust.


MiniXChain is an open consortium chain based on the Substrate framework and adopting the aura + grandpa consensus. It will be implemented as a Parachain of ChainX through the Spider cross-chain protocol. MiniXChain will support the launch of applications such as DID/NFT. Coming will be the first use case to deploy its decentralized digital identity CID and NFT applications to the MinixChain alliance chain, using Mini points as a fee.

Development progress:
1. Completed the decentralized digital identity CID. CID is the user’s digital identity in ComingChat. At present, more than 100,000 users have used CID to log in and use ComingChat.
2. The design and implementation of C-CARD NFT have been completed. At present, more than a dozen sets of NFTs have been issued. Users can sell NFTs to others through transactions, auctions, etc. Most users have shown a very strong interest.

Research Articles

Below you will find the raw research articles the team completed on various subjects. These are to learn more about the possibilities and the applications of technology to the ChainX ecology.

Privacy protection based on Taproot

Schnorr signature and Musig aggregate signature principle

Transition from SegWit V0 to SegWit V1

Shamir’s Threshold Red Envelope Scheme

Implementation of EVM on Substrate

About ChainX

ChainX, the earliest launched project in Polkadot’s ecosystem, is committed to the research and application of Bitcoin layer 2 expansion, digital asset gateway and Polkadot second-layer relay chain, to realize cross-chain asset exchange, leading the new direction of Bitcoin Cross-DeFi.

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ChainX is a BTC Layer 2 solution compatible with EVM that utilizes Bitcoin as a gas fee, serving as the predecessor network of BEVM.