Blockchain: Decentralized communication facilitates interoperability

Blockchains will have to be able to communicate with each other if the development of the technology is to pick up speed. Blockchain startup Toposware joined forces with CEA-List to develop a blockchain interoperability protocol that does away with a central authority.

Innovative cross-chain solutions like this will be crucial to Web 3.0

Bitcoin—now fifteen years old—put blockchain on the map. Today, the technology is deemed essential to the next incarnation of the internet. Web 3.0 will be blockchain-based. Tomorrow’s decentralized web will operate without a central authority. But first, blockchain stakeholders will have to innovate to address several challenges:

  • Scalability: Today’s blockchains can only handle a limited number of participants and transactions per second.
  • Privacy: Information must be proven using data that businesses and individuals are not always eager to share.
  • Interoperability: There are already many different blockchains that cannot communicate with each other.

The purpose of the Toposware project is to find solutions to these issues. And the CEA is contributing its knowledge of distributed systems. CEA-List has a strong track record with several partnerships and publications around blockchain. The institute has worked on the Tendermint blockchain and helped draw up specifications for Tenderbake, the protocol used by Tezos.

A communication protocol without a central authority

Toposware and CEA-List will be focusing on cross-chain communication systems. Together, they will tackle the challenge of making sure messages sent by different blockchains are “seen” in the correct order. Currently, messages can be seen in different orders by different blockchains—something that is problematic for financial transactions.

One solution is to use a central blockchain to set up communication between different blockchains. Another is for the participants in the sending and receiving blockchains to handle communication, in which case the blockchains must give up the privacy of their data. The Toposware project will result in a new cross-chain communication protocol that does not require a central authority. The project partners have opted for a causal order broadcast protocol that maintains the order of the messages sent.

Incentives to reinforce the system

CEA-list and Toposware also investigated how to best implement incentives for users to ensure that the protocol works optimally—with no cheating. A blockchain is a self-managed system. So, users can do whatever they want, at least in theory. Spending cryptocurrency twice is a well-known example. Because there is no physical money, the same coin could theoretically be sold twice to two different people. But there are protocols designed to prevent this kind of fraud, usually by making “bad” behaviors either very complicated or in some way unfavorable to the actor and by encouraging, through incentives, “good” behaviors. Applying an incentive mechanism to a causal order broadcast protocol could effectively ensure that, when a blockchain sends a cross-chain transaction, it is duplicated properly across all the nodes in the system.

The foundation for advances in DeFi

The project, which kicked off in October 2021, could start producing results by the fall of 2022. The decentralized finance, or DeFi, industry, which uses multiple blockchains, could be among the first to benefit from the advances made. The new protocol could also allow DApps, the decentralized apps deployed on the blockchain, to be reused on multiple blockchains, for instance.  More broadly, the project will remove some of the hurdles to the widespread adoption of blockchain technology.

Interview with Théo Gauthier, CEO, Toposware

What made you want to work with CEA-List?

CEA-List’s knowledge of distributed systems was a crucial addition to our own areas of expertise, cryptography and blockchain.


The project got off the ground in October 2021. What have you accomplished so far?

We have already put out a white paper. We are also planning several other publications, co-authored with the CEA, on incentive mechanisms and Sybil attacks.


How will the results of the project be used?

Topos, our cross-blockchain solution, wasn’t scalable. Our partnership with CEA-List produced the primitive that will allow us to scale.

Théo Gauthier

CEO — Toposware