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Study Union.
Union is a modular interoperability protocol which facilitates the exchange of assets and messages between blockchains & dApps.
Union leverages two key innovations. First is consensus verification, where validators on one chain verify that consensus was achieved among validators on another chain before accepting a transfer.
Combined with this is secure zero-knowledge cryptography, which reduces the computing power and gas required to facilitate a transfer.
Together, this means fast and cost-effective connection between protocols across any execution environment with zero trusted actors.
Interoperability in blockchains refers to their ability to pass messages and communicate with each other.
Union enables developers to build with any execution environment or language (such as Solidity, Rust, and Move), and connect their blockchain or dApp to any ecosystem. This removes UX bottlenecks stemming from fragmented networks.
Modularity in crypto refers to when a blockchain system is built using interchangeable, self-contained components that can be developed, updated, or replaced independently. This approach enhances flexibility, scalability, and maintainability by allowing developers to focus on specific functions or features without affecting the entire system.
Union’s modularity solutions span across the entire Union ecosystem:
Prove: ZK proofs, or ZKPs, are the backbone of Union’s network. They are mathematical, indisputable proofs of correctness of the cross-chain state generated by a network of solvers.
Verify: Through ZKPs, any chain or end user can securely verify a blockchain’s state across ecosystems using Union light clients or other proof aggregators.
Integrate: Combine the proving stack and the verification stack to build any type of connection: IBC, ISM, GMP, or ICS. Access protocols on different chains using any standard.
Message Passing: Securely transmit messages between chains to enable applications like decentralized exchanges (DEXs) and lending protocols to work together.
Asset Transfers: Facilitate the cross-chain transfer of fungible assets, such as native assets or staked derivatives, between any chain integrated with the Union network.
Cross-chain NFTs: Transfer NFTs between chains by ensuring efficient mapping and encoding of NFT data across different standards (e.g., ERC-721, ICS-72).
These are just a few examples. There are no limits to what can be done with the state proofs generated by Union in an infinitely scalable blockchain future.
Think of Union as a zero-knowledge proof (ZKP) network where the state of each chain resides. When a new blockchain integrates with Union, it gets a Union light client that verifies mathematically secure ZKPs generated from the counterparty chains.
Anytime a user sends a transaction from Chain A to Chain B, a ZKP is generated on Chain A through one of the proving markets supported by Union, or directly on bare-metal hardware. The prover then submits the ZKP to Chain B, where an on-chain verifier—a smart contract or L2 module—confirms the Merkle inclusion proof that Chain A sent the message. Once the ZKP is verified, all transactions up to that ZKP are immediately settled, allowing the prover to settle large batches of transactions.
Within the light client on Chain B, consensus verification is used to show that the validators of Chain A signed the Merkle root. In zero-knowledge based IBC, this consensus verification is achieved by verifying a ZKP of consensus on-chain. Provers generate ZKPs of consensus by confirming that the validators signed a block’s Merkle root within a zero-knowledge circuit.
This system is designed so that anyone can generate a ZKP of consensus on consumer-grade hardware, eliminating censorship risk. There are no trust assumptions on the prover, nor centralized components like an oracle or multi-sig. Even if Union's creators ceased to exist, the outlined transaction flow would continue permissionlessly into eternity.
State verification between blockchains is often gas-intensive due to the complexity of verifying consensus on other chains with varied structures and execution environments. This is why many ecosystems turned to trusted third parties such as single-signature, multi-sig, and MPC bridges for interoperability.
With Union, trusted third parties are no longer necessary. Consensus verification unlocks trust-minimized interoperability between blockchains, and zero-knowledge cryptography makes the process scalable, cost-efficient, and fast. Union extends the gold standard of the Inter-Blockchain Communication Protocol (IBC) to all of web3 with ZK-powered consensus verification, unlocking trustless communication between blockchains.
The Inter-Blockchain Communication Protocol (IBC) functions similarly to TCP/IP, and facilitates communication between independent blockchains. Blockchains that support IBC can establish connections with other IBC chains, allowing one blockchain to verify proofs against the consensus state of another using a light client. This enables robust interoperability among IBC-compatible blockchains, including asset transfers, atomic swaps, cross-chain decentralized exchanges, and even cross-chain smart contracts. IBC has been gaining widespread adoption, making it a promising candidate as the governing interoperability standard of Web3.
Galois is the umbrella term of Union's ZK efforts. It currently has one purpose: consensus verification.
We've built Galois around three fundamental principles: fast execution, low-cost operation, and decentralization. The architecture involves three key steps for transactions through Union: Emitting a send-packet event, generating a zero-knowledge proof (ZKP) of the Union state, and updating the counterparty with the Union state, which promotes accessibility for all participants in the system.
Galois can outperform other zero-knowledge bridges while operating on a single machine, avoiding the need for large clusters.
CometBLS is the enhanced blockchain consensus engine underpinning the Union network. Building upon Tendermint, CometBLS addresses the challenges of secure bridging and consensus verification.
Unlike Tendermint, CometBLS is tailored for efficient zero-knowledge proving, which is crucial for bridging to blockspace-restricted chains like Ethereum. Leveraging BLS signatures as its foundation, CometBLS reduces proving times, facilitating faster and cost-effective bridging transfers. The utilization of BLS signatures enables the aggregation of public keys and signatures, minimizing transaction size and on-chain computation costs.
Under CometBLS, the Union network can seamlessly scale to over a hundred validators without compromising performance or bridging latency, ushering in a new era of secure and scalable blockchain consensus.
The IBC protocol relies on off-chain actors for the transfer of packets and proofs between chains. Union’s in-house relayer, Voyager, facilitates support for new networks independently of upstream assistance.
Voyager’s architecture is event-driven, employing an internal memory queue for observed events and I/O processes. Voyager integrates with Galois through gRPC, enabling the offloading of computation to dedicated hardware, with upcoming support for proving markets.
This design ensures efficient communication and flexibility in supporting diverse blockchain networks.