Wanchain 4.0 T-Bridge Framework Tech Explainer: Part 1 — General Overview

How the T-Bridge (Trusted-Bridge) Framework Enables Universal Blockchain Connections (Including Public-Private Connections)

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Wanchain

6 min readFeb 19, 2020

One of Wanchain’s core missions is to tackle the thorny problem of blockchain interoperability. The importance of cross-chain interoperability has only grown more apparent with the proliferation of different public and private blockchains. The problem is compounded by the fact that many popular blockchains are heterogenous (meaning they are built with fundamentally different technological architectures — consensus mechanisms, smart contract languages, etc.).

As blockchain begins to gain more acceptance and institutional usage worldwide, more and more assets will start to move to private chains, as only they allow for the required controls needed to be legally compliant with various regulatory bodies around the world. The release of the Wanchain 4.0 and the T-Bridge framework fills this need and is currently the first and only standardized framework for which tackles the problem of private to public blockchain interoperability.

In our Wanchain 4.0 release article, we announced the release of our new T-Bridge (Trusted-Bridge) framework, a general framework, and reference architecture with modular components and protocols which are compatible with Wanchain’s original Storeman cross-chain mechanism currently used for the public to public blockchain connections. The T-Bridge framework links components in a source chain, target chain, and routing chain together and defines standard components and protocols to enable cross-chain transactions (CCT). In this article, we give a broad technical overview of the T-Bridge framework.

Meet The T-Bridge Architect

**James Zhu:** Wanchain Director of Engineering

The T-Bridge framework was designed by the Wanchain Director of Research and Development, James Zhu. James is a graduate of the Peking University School of Mathematical Sciences with undergraduate and graduate degrees in information research and computer software. James has over 20 years of work experience in blockchain, big data analysis, internet and mobile platforms, distributed computing, telecommunications networking, SaaS platforms, and more. He held previous positions in Nortel Networks, Ericsson, Nokia, and several other high profile internet companies. He has carried out in-depth analysis and research on the technologies and scenarios of many major blockchain platforms and created Wanchain’s enterprise chain Lanchain product series and components.

What Exactly is the T-Bridge Framework?

The T-Bridge framework is a standardized, universal framework which allows for the exchange of assets and data between blockchains:

Standardized — The T-Bridge framework is standardized according to specifications based on formal methods. This is a way to formally describe the framework specifications using a logically consistent language that allows for implementation in a wide variety of different computing environments and with various blockchains.

Universal — This means that T-Bridge is designed to be implemented on any blockchain with smart contract capabilities regardless of its underlying technical design, such as consensus mechanism or smart contract language. This also means it allows for Public-Public, Private-Private, and Private-Public blockchain connections.

Assets and Data — By this, we mean that the framework not only allows for the circulation of assets between blockchains (as Wanchain currently does now with Ethereum/ERC20 tokens, BTC, and EOS) but also allows for data to be shared between different blockchains. This allows for the creation of complex cross-chain decentralized applications where transactions on one chain can be triggered by events which occur on another chain

How Does the T-Bridge Framework Work?

A simplified summary of how the T-Bridge framework works:

The T-Bridge framework allows for users and service providers on different blockchains to engage in cross-chain transactions by interacting with smart contracts deployed on their respective chains. An intermediary router chain is used to register and sync necessary information related to cross-chain transactions. Protocol mediators monitor the state of different chains. They are able to issue transactions on one chain based on events that happen on another chain (this is roughly equivalent to the role of Storeman Nodes in Wanchain’s current solution for Public to Public cross-chain interoperability).

**Figure 1: General Overview of the T-Bridge Framework**

Definition of Key Concepts and Actors:

Router Chain (Chain Router in Figure 1): The router chain is the connecting hub for cross-chain transactions between business chains within the T-Bridge framework.
Business Chain (Chains A and B in Figure 1): Business chains are involved in CCT transactions for providing related services or resources.
Protocol Mediator (PM): The protocol mediator provides cross-chain transaction mechanisms across router and business chains via the T-Bridge framework. It monitors chains for aggregations and performs corresponding cross-chain transaction requests.
Service Provider (SP): SP provides services or resources that are involved in cross-chain transactions.
User (U): User initiates transactions for the exchange of cross-chain resources or services.
CCT Contracts (Part of CCT contracts in Figure 1): CCT contracts provide the T-Bridge framework with various essential functions such as a cross-chain registry mechanism, supported trust models, basic CCT info, and more (The CCT Contracts will be discussed more thoroughly in Part 2).
BIZ Contracts: The BIZ contracts provide essential services that supplement the core CCT Contracts. The BIZ Aggregation and BIZ Service/Pair Contracts will be discussed more thoroughly in part two.

What does the T-Bridge Technical Stack look like?

The Wanchain R&D team has provided the following possible technical stack for illustrative purposes:

This is an abstracted depiction of the technical stack which does not specify exact technologies or implementation details. The details will vary from implementation to implementation. The T-Bridge proof of concept currently under development by the Wanchain team (more info about the proof of concept will be published shortly), makes use of Wanchain as both the router and business chain, and of Hyperledger’s Besu as a second business chain to be connected. Storage for the Chain Agent’s querying of blockchains is done with MongoDB, and ChainServices (not pictured in Figure 2) act as a supplement and improvement of ChainAgent for communication with blockchains which allow the Protocol Mediator to query blockchain info and send blockchain transactions. For more in-depth details about the proof of concept implementation, please stay tuned for the detailed specifications, which will be released shortly.

Part 2 Coming Soon!: Learn about CCT / BIZ Contracts, Conceptual Models, and more!

Stay tuned for Part 2 of the T-Bridge Framework Tech Explainer series, where we will discuss in more detail the CCT and BIZ Contracts, which power the T-Bridge framework and the conceptual models which guide the design of the framework.

About Wanchain

Wanchain is the infrastructure connecting the decentralized financial world. Wanchain’s live cross-blockchain solution is EVM-based, includes optional private transactions, and provides a decentralized, permissionless, and secure approach for interoperability. Wanchain has employees globally with teams in Beijing (China), Austin (USA), Kuala Lumpur (Malaysia), and Madrid (Spain).