▶️Interchain Queries

Interchain Queries Module Overview

The Interchain Queries (ICQ) Module facilitates asynchronous query-callback interactions between Quicksilver and remote blockchains, enabling Quicksilver to request, receive, and verify specific data from those chains. Quicksilver’s ICQ is the original implementation—predating more recent “IBC-baked” standards—using an external relayer rather than official ICS (Interchain Standards) for data packet transmission. Despite this, it still provides trust-minimized data retrieval, relying on Merkle tree proofs (or equivalent verification methods) to ensure data integrity.

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Key Objectives

1. Secure Cross-Chain Data Retrieval

   • Provide a reliable mechanism to fetch and verify chain-specific data (e.g., account balances, validator statuses) without relying on centralized intermediaries.

   • Rely on cryptographic proofs (such as Merkle proofs) to validate the authenticity and integrity of the data.

2. Asynchronous Query-Callback Workflow

   • Requests for information are dispatched to the remote chain via an external relayer, allowing Quicksilver to continue processing without waiting for immediate responses.

   • When the remote chain (or the relayer) returns data and proofs, the ICQ Module invokes a callback in the requesting module to handle that data.

3. Broad Adoption Across Cosmos

   • Quicksilver’s original ICQ architecture has been used and adapted by multiple protocols in the Cosmos ecosystem, proving both flexible and resilient over time.

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How Quicksilver’s ICQ Works

1. Query Creation

   • A Quicksilver module (e.g., Interchain Staking, Participation Rewards) crafts a query request, specifying the remote chain, the target data (e.g., delegation amounts), and callback details for when data returns.

2. External Relayer Transmission

   • The request is forwarded to an external relayer (rather than being included in an IBC packet).

   • This relayer is responsible for routing the query to the target chain and listening for the response.

3. Remote Chain Processing & Proof Generation

   • The remote chain executes the query, collects the requested data, and builds a cryptographic proof (often a Merkle branch) attesting to the correctness of that data relative to the chain’s state root.

4. Response & Proof Validation

   • The external relayer delivers the data and proof back to Quicksilver’s ICQ Module.

   • Quicksilver verifies the proof against a trusted header or light-client state for the remote chain, ensuring the data has not been tampered with.

5. Callback Invocation

   • Once verified, the ICQ Module calls back into the requesting module, which then processes the data (e.g., updating delegations, distributing rewards, or adjusting redemption rates).

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Why an External Relayer?

• Historical Context Quicksilver’s ICQ implementation predates newer ICS-based query methods (sometimes referred to as “IBC-baked” queries) by approximately 18 months.

• Proven Effectiveness Despite not conforming to newer ICS standards, Quicksilver’s external-relayer approach has been thoroughly battle-tested and adopted by various protocols, demonstrating its reliability and scalability.

• Community Collaboration Multiple projects in the Cosmos ecosystem have worked to refine and extend Quicksilver’s ICQ approach, building a vibrant ecosystem of cross-chain tools around it.

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Merkle Tree Proofs & Cryptographic Security

Although Quicksilver’s ICQ does not rely on standard IBC channels for communication, it still preserves a trust-minimized model via Merkle tree proofs (or analogous cryptographic structures):

• Consistency with Remote Consensus If the remote chain attests that a given piece of data (e.g., account balance, validator performance) is included in its state root, that data becomes verifiable on Quicksilver’s side.

• No Centralized Oracles Because the proof is tied to the remote chain’s consensus state, there is no single point of trust or third-party oracle controlling data validity.

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Use Cases

1. Interchain Staking

   • Retrieving delegator balances, rewards, and slashing information from a remote chain ensures accurate management of Quicksilver’s liquid staking positions.

2. Participation Rewards

   • Queries can verify validator performance or governance participation, enabling Quicksilver to distribute QCK incentives to users aligning with network goals.

3. Governance by Proxy

   • Verifying user stake or voting data on the remote chain ensures cross-chain voting power is accurately reflected within Quicksilver’s governance processes.

4. General Cross-Module Needs

   • Any module that requires trusted data from external chains (e.g., for bridging assets, verifying identity, or orchestrating multi-chain DeFi) can leverage Quicksilver’s ICQ approach.

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Future Directions

• Harmonization with Emerging Standards While Quicksilver’s ICQ implementation is distinct from newer ICS query specifications, future updates may explore partial or full integration with standard IBC-based solutions for increased cross-chain compatibility.

• Extended Data Formats As remote chains introduce more complex state structures, Quicksilver’s ICQ may expand to accommodate advanced or custom proof types.

• Further Ecosystem Adoption Continued collaboration and contributions across the Cosmos community can help refine the external relayer approach and open up new interchain functionalities.

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Conclusion

Quicksilver’s original Interchain Queries (ICQ) Module, supported by an external relayer mechanism, has been a pioneering force in cross-chain data retrieval. It provides asynchronous, cryptographically secured queries that enable safe and efficient interchain operations—from liquid staking to governance management. Though newer ICS-based solutions exist, Quicksilver’s ICQ remains a robust, widely adopted model, continuously evolving with the support of the Cosmos community.