How the Proof Flow WorksHow the Proof Flow Works

Proof Receipt Structure

{
  "proofId":     "0x3f8a2c1d9e…",          // Short handle for the proof
  "imageId":     "a4f2…",                   // SHA256 of the zkVM guest program ELF
                                             // Identifies WHAT computation was run
  "journalHash": "8b3c…",                   // SHA256 of the public outputs
                                             // Commits to the oracle readings + verdict
  "seal":        "f91d…",                   // ZK proof bytes (STARK/SNARK)
                                             // Mathematical guarantee of honest execution
  "journal": {
    "oracle1_source": "Open-Meteo Forecast (ECMWF IFS)",
    "oracle1_mm":     12.4,
    "oracle2_source": "Open-Meteo ERA5 Archive (ECMWF ERA5)",
    "oracle2_mm":     10.8,
    "oracle3_source": "NASA POWER PRECTOTCORR",
    "oracle3_mm":     9.3,
    "consensus_mm":   10.8,
    "threshold_mm":   40,
    "is_drought":     true,
    "timestamp":      1744560000
  }
}

zkVM Guest Program (Rust)

// Reads oracle JSON from host, computes drought consensus, commits to journal
fn main() {
    let input_bytes: Vec<u8> = env::read();
    let input: GuestInput = serde_json::from_slice(&input_bytes).unwrap();

    // Filter available oracles (value >= 0), compute average
    let readings: Vec<f64> = [o1, o2, o3, o4, o5]
        .iter().filter(|&&v| v >= 0.0).cloned().collect();

    let consensus_mm = readings.iter().sum::<f64>() / readings.len() as f64;
    let is_drought   = consensus_mm < input.threshold_mm;  // 40mm threshold

    // Commit public outputs — what the ZK proof guarantees
    env::commit(&GuestOutput {
        farm_id, consensus_mm, oracles_used: readings.len() as u32,
        is_drought, threshold_mm, timestamp,
        oracle1_mm, oracle2_mm, oracle3_mm, oracle4_mm, oracle5_mm,
    });
}