To integrate off-chain data feeds into Sui smart contracts without creating centralization or heavy trust assumptions, you should use a decentralized oracle design where multiple independent data providers submit signed values on-chain, and your smart contract aggregates or validates these submissions before accepting them. Avoid relying on a single off-chain source; instead, design your oracle interface to require data from a quorum of trusted nodes or validators, and use threshold signatures, majority voting, or median filtering to determine the final value. All submitted data should be signed off-chain and verified on-chain using public keys to ensure authenticity without needing shared mutable state.

To minimize trust, your contract logic should allow dynamic updates to the list of trusted oracles and apply slashing or exclusion mechanisms for misbehavior. You can also use a time-based anchoring system where data submissions are only valid within a certain time window, preventing replay attacks.

For more insights, see decentralized oracle frameworks discussed in the Sui ecosystem here.

Here’s a simplified Move example of handling decentralized oracle submissions:

module DecentralizedOracle {
    struct OracleSubmission has store {
        value: u64,
        timestamp: u64,
        signer: address,
    }

    public fun verify_submission(submission: &OracleSubmission, allowed_oracles: vector<address>): bool {
        vector::contains(&allowed_oracles, &submission.signer)
            && is_fresh(submission.timestamp)
    }

    fun is_fresh(timestamp: u64): bool {
        // Accept data within 5-minute window (example)
        let current_time = Timestamp::now(); 
        current_time - timestamp < 300
    }
}

This pattern lets you collect multiple signed values from decentralized sources, verify authenticity and freshness, and aggregate safely without centralized trust points.