Sybil Detection

import httpx

def trace_funding_source(wallet: str, api_key: str, max_hops: int = 2) -> list[str]:
    """Trace SOL funding sources for a wallet via Helius parsed transactions."""
    url = f"https://api.helius.xyz/v0/addresses/{wallet}/transactions"
    resp = httpx.get(url, params={"api-key": api_key, "type": "TRANSFER", "limit": 50})
    transfers = resp.json()

    funders = []
    for tx in transfers:
        for transfer in tx.get("nativeTransfers", []):
            if transfer["toUserAccount"] == wallet and transfer["amount"] > 0.001 * 1e9:
                funders.append(transfer["fromUserAccount"])
    return funders

def detect_co_trades(buy_events: list[dict], slot_window: int = 3) -> list[list[str]]:
    """Group wallets that bought within the same slot window."""
    buy_events.sort(key=lambda x: x["slot"])
    clusters = []
    current_cluster = [buy_events[0]]

    for i in range(1, len(buy_events)):
        if buy_events[i]["slot"] - current_cluster[0]["slot"] <= slot_window:
            current_cluster.append(buy_events[i])
        else:
            if len(current_cluster) >= 3:
                clusters.append([b["wallet"] for b in current_cluster])
            current_cluster = [buy_events[i]]

    if len(current_cluster) >= 3:
        clusters.append([b["wallet"] for b in current_cluster])
    return clusters

def check_bundle_ratio(early_buys: list[dict], bundle_window_slots: int = 5) -> dict:
    """Calculate the ratio of bundled vs independent early buys."""
    bundled = [b for b in early_buys if b.get("is_bundled", False)]
    first_slot = min(b["slot"] for b in early_buys) if early_buys else 0
    early = [b for b in early_buys if b["slot"] - first_slot <= bundle_window_slots]

    return {
        "total_early_buys": len(early),
        "bundled_buys": len(bundled),
        "bundle_ratio": len(bundled) / max(len(early), 1),
        "bundled_supply_pct": sum(b["amount"] for b in bundled) / max(sum(b["amount"] for b in early), 1),
    }

def detect_wash_cycles(transfers: list[dict], holder_set: set[str]) -> list[tuple]:
    """Find circular transfer patterns among known holders."""
    # Build directed graph of transfers between holders
    edges: dict[tuple, float] = {}
    for t in transfers:
        if t["from"] in holder_set and t["to"] in holder_set:
            key = (t["from"], t["to"])
            edges[key] = edges.get(key, 0) + t["amount"]

    # Find reciprocal pairs (A->B and B->A both exist)
    wash_pairs = []
    for (a, b), vol_ab in edges.items():
        vol_ba = edges.get((b, a), 0)
        if vol_ba > 0:
            wash_pairs.append((a, b, vol_ab, vol_ba))
    return wash_pairs

def compute_sybil_score(metrics: dict) -> dict:
    """Compute composite sybil risk score from individual metrics."""
    weights = {
        "funding_cluster": 25,    # Wallets from same funder
        "co_trade": 20,           # Coordinated buy timing
        "bundle_ratio": 20,       # Bundled early transactions
        "unique_funder": 15,      # Diversity of funding sources
        "transfer_density": 10,   # Internal transfers between holders
        "wash_trade": 10,         # Circular trading patterns
    }

    scores = {}
    # Each sub-score normalized to 0-1, then weighted
    scores["funding_cluster"] = min(metrics.get("max_cluster_size", 0) / 20, 1.0)
    scores["co_trade"] = min(metrics.get("co_trade_pct", 0) / 0.3, 1.0)
    scores["bundle_ratio"] = min(metrics.get("bundle_ratio", 0) / 0.5, 1.0)
    scores["unique_funder"] = 1.0 - min(metrics.get("unique_funder_ratio", 1.0), 1.0)
    scores["transfer_density"] = min(metrics.get("transfer_density", 0) / 0.3, 1.0)
    scores["wash_trade"] = min(metrics.get("wash_pairs", 0) / 5, 1.0)

    composite = sum(scores[k] * weights[k] for k in weights)
    risk_level = "LOW" if composite < 30 else "MEDIUM" if composite < 60 else "HIGH"

    return {"score": round(composite, 1), "risk_level": risk_level, "components": scores}

# 1. Get top holders
holders = get_top_holders(token_mint, rpc_url)

# 2. Trace funding sources for each holder
funding_map = {}
for wallet in holders[:30]:  # Top 30 is usually sufficient
    funding_map[wallet] = trace_funding_source(wallet, helius_key)

# 3. Cluster by common funder
clusters = cluster_by_funder(funding_map)

# 4. Check co-trade timing
early_buys = get_early_buy_events(token_mint, helius_key)
co_trade_groups = detect_co_trades(early_buys)

# 5. Check for bundles
bundle_stats = check_bundle_ratio(early_buys)

# 6. Check wash trading
transfers = get_token_transfers(token_mint, helius_key)
wash_pairs = detect_wash_cycles(transfers, set(holders))

# 7. Compute composite score
metrics = {
    "max_cluster_size": max(len(c) for c in clusters) if clusters else 0,
    "co_trade_pct": sum(len(g) for g in co_trade_groups) / len(holders),
    "bundle_ratio": bundle_stats["bundle_ratio"],
    "unique_funder_ratio": len(set(f for fs in funding_map.values() for f in fs)) / len(holders),
    "transfer_density": len(wash_pairs) / max(len(holders), 1),
    "wash_pairs": len(wash_pairs),
}
result = compute_sybil_score(metrics)
print(f"Sybil Risk: {result['risk_level']} ({result['score']}/100)")