The Real Inter-chain Technology Consists of Two Steps: Locking and Mapping

4 min readJul 21, 2020

Great Coordination Forged by ChainX, Filcion and Polkadot in Transforming Infrastructure Ecosystem

ChainX pays attention to IPFS and Filcoin very early on. Even the earliest whitepaper of the two are translated by us. When Polkadot was launched this year, we think the time was ripe for us to create a new infrastructure ecosystem by integrating Polkadot and Filcoin. To do that the first step is to participate in the Filcoin ecosystem.

1. Inter-chain Advantage Helps ChainX Embrace Filcoin!

This spring saw we start undertaking IPFS related business. As the first public chain operating on the Substrate framework and the first to explore inter-chain projects on Polkadot, ChainX is no stranger to the Polkadot/Substrate code system, based on which, we successfully mastered the BTC light node inter-chain technology which has been running smoothly for a year. And we decided to start with what we do best, obviously the inter-chain technology, to develop a FIL transfer bridge for the Filcoin system.

2. ChainX’s Inter-chain Technology is Completely Decentralized.

What are our inter-chain advantages? To answer that, we need to figure out what inter-chain means. We’re understandably confused by the name. Inter-chain means crossing chains literally, but it’s not correct. The true meaning is not unveiled until we figure out the inter-chain process.

Take BTC crossing onto Ethereum. Is it a technological breakthrough that we’ve made to directly connect Bitcoin system and Ethereum, so that BTC can cross those chains freely? The answer is no, because either coins or tokens, down to the bare bone, are encrypted data on chains. Given the fact that Bitcoin and Ethereum are two separate and utterly different systems in terms of data structure and network context, there is no direct crossing path between them that doesn’t incur any loss or damage.

The real inter-chain technology consists of two steps: locking and mapping. Lock assets on the original chain and map them onto the target chain as shadow assets, and vise versa, unlock the assets by destroying the shadow ones. Mapping and destroying assets are the core of the inter-chain technology in which intermediate roles are played by codes only. No human or institution is trusted to perform the role for fear of incomplete decentralization or compromised security.

However, currently most of the role’s undertakers are somewhat centralized, such as individual trustee, multi-party trustee, or more blatantly, exchangers with transparency and security at stake.

ChianX’s edge is to replace these centralized intermediaries with its code system. The light node sidechain relay technology is deployed to ensure complete decentralization and uncompromised security.

3. Two-way decentralization can be achieved if ChainX transfer bridge reaches Filcoin.

Why is there so few successful example of two-way decentralization? Partially because the bitcoin system is not flexible and extensible enough to allow it and partially because inadequate knowledge of light nodes is hampering the way ahead.

Satoshi Nakamoto writes in the Bitcoin whitepaper the light node protocol which states if the target chain integrates all the light nodes of the original chain, assets mapped onto the target chain should be protected by the consensus algorithm of the original chain. It is the consensus algorithm not some centralized system that protects the assets. So light node inter-chain technology is both secure and decentralized.

It takes ChianX one year to integrate all Bitcoin light nodes and afterwards map BTC onto ChainX as X-BTC in a decentralized way by the ratio of 1:1 with adequate reserve fund as backing.

Bitcoin block heads submitted are to be verified by ChianX according to pow to calculate the longest chain. All Bitcoin transactions can be verified by Merkel, which makes ChainX a sidechain of Bitcoin. This remarkable achievement also places ChianX ahead of the curve in the field. Shortly after the mainnet was launched, bitcoins worth tens of millions of dollars were mapped onto ChianX. The number of inter-chain BTC soon overtook that of the lighting network and nearly 20,000 bitcoins were in lock-up at the height, which make ChianX the largest sidechain and second-layer network of Bitcoin.

At the same time, ChainX won wide support for OP_RETURN from many popular BTC wallets. OP_RETURN is of attachment function, a necessary step before chain crossing. This lays a solid foundation for wider use of inter-chain BTC in the future.

On ChainX mainnet an inter-chain BTC transaction is settled within 2 seconds with service fee as low as 0.1 cent and throughput up to 1000 TPS. Inter-chain BTC joining Polkadot in the future also bodes well for more throughput and application scenarios.

These are the progress we have made in this regard so far with experiences to share. In short, the same BTC inter-chain technology will also be used in the transfer bridge with Filcoin but with a tweak, to put it more precisely, the deployment of smart contract. Without it, decentralization is partially compromised as in BTC case multi-signed trustees are needed to honor the unlocking process by destroying the shadow assets. With it, two-way decentralization inter-chain technology between Filcoin and ChainX can operate smoothly.

About ChainX




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