Union Labs raises $4 million to develop cross-chain bridge enabled by ZK proofs

Blockchain interoperability developer Union Labs has raised $4 million in seed funding to build a bridge connecting different Layer 1 and Layer 2 networks with zero-knowledge (ZK) proofs.

The investment was led by venture firms including Galileo, Semantic Ventures, Tioga Capital, and Nascent. Other investors in the round include Lightshift and Chorus One. The capital raised will be used for hiring and expansion efforts.

Unlike contemporary bridging solutions, Union does not grant relayers special authority, ensuring private keys are not a target for security hacks, as they cannot take control of the protocol. Messages are verified using ZK proofs instead.

“The most prominent hacks are bridge hacks, yet bridges remain critical infrastructure for almost all projects, showing the need for better, more resilient products. It is our responsibility to innovate new ways to protect these assets and further the adoption of ZK technologies to realize a secure and interoperable cross-chain future,” said Karel Kubat, founder of Union Labs.

Architectural breakdown: Union’s ZK bridge components

Union’s ZK bridge architecture includes two key components that enable the project to facilitate Cosmos’ communication protocol, known as IBC, on Ethereum; CometBLS, the consensus mechanism, and Galois, the zero-knowledge prover system.

Union’s CometBLS consensus allows the transfer of any asset natively to any chain without relying on third parties, oracles, or multi-signatures (multi-party computation). CometBLS augments Cosmos’ Tendermint consensus, according to the team.