Oracle Contract

Price Feed Oracle Contract

Chainsight typically deploys an Oracle contract on the target EVM chain, which can store arbitrary data keyed by (sender, key). Below is a simplified explanation of how it works:

function updateStateByKey(
        bytes calldata _data,
        bytes32 key
 ) external override {
    // Store the price data under (msg.sender, key).
    // The block timestamp is recorded for checking the updated time.
}

function readAsUint256WithTimestamp(address sender, bytes32 key)
    external view
    returns (uint256, uint64)
{
    // Return the uint256 value plus the timestamp
}

// Overloads for other data types (string, int256, etc.)

Key Points & Interface Highlights

1. updateStateByKey(...)

   • Chainsight (or any authorized sender) writes data to the contract, specifying a unique key (often a bytes32 that references the price feed name or asset).

   • The contract automatically timestamps each update.

2. readAsUint256WithTimestamp(...)

   • DApps call this to retrieve the stored 256-bit integer plus the last update’s timestamp. It’s the primary function for price retrieval.

   • The contract also supports readAsString..., readAsInt..., etc., for more advanced or text-based data.

In short, developers can read the most up-to-date on-chain data by calling readAsUint256ByKey(sender, key), receiving the integer plus a timestamp.

GitHub - horizonx-tech/chainsight-management-oracle: Oracles supported by ChainsightGitHub

Writing Data to Each Chain

Internally, chainsight uses a distributed node approach with threshold ECDSA based on the chain-key cryptography:

1. Canister Node Collects or Generates Data

   • The node network finalizes data (like a price or time-series point).

2. Threshold Signing

   • The node network collectively signs an EVM transaction using a shared private key (generated by DKG).

   • This private key is never held by a single party. Instead, each node holds a partial share—only by combining a threshold of shares can they produce a valid signature.

3. Transaction Submission

   • The final signed transaction is broadcast to the EVM chain, calling updateStateByKey(...) on the Oracle contract.

   • No external bridging contract is required, as the node network “natively” signs an Ethereum-compatible tx.

Note: This entire process is cryptographically distributed. No single node can forge or block updates, ensuring decentralized reliability.