File size: 2,638 Bytes
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Fraud engine — suspicion tracking and fraud intensity for adaptive publishers.
"""
from __future__ import annotations
from typing import Any, Dict
# ── Suspicion tracking ────────────────────────────────────────────────────
def update_suspicion(
current_level: float,
tool: str,
reactivity: float,
) -> float:
"""Increase suspicion after an investigation tool is used on a fraudster.
Each tool adds a fixed bump scaled by the publisher's reactivity.
"""
bump = {
"click_timestamps": 0.15,
"ip_distribution": 0.12,
"device_fingerprints": 0.10,
"referral_urls": 0.10,
"viewability_scores": 0.08,
"conversion_quality": 0.10,
}.get(tool, 0.10)
return min(1.0, current_level + bump * reactivity)
def decay_suspicion(level: float, rate: float = 0.05) -> float:
"""Decay suspicion each day a fraudster is NOT investigated."""
return max(0.0, level - rate)
def get_adaptation_stage(suspicion_level: float) -> str:
"""Map suspicion level to an adaptation stage for response generation."""
if suspicion_level >= 0.8:
return "dark"
if suspicion_level >= 0.5:
return "covering_tracks"
if suspicion_level >= 0.25:
return "cautious"
return "normal"
# ── Fraud intensity ───────────────────────────────────────────────────────
def compute_fraud_intensity(
day: int,
fraud_schedule: Dict[str, Any],
adaptation_stage: str,
) -> float:
"""Compute how aggressively a publisher is committing fraud on a given day.
``fraud_schedule`` comes from the case profile and has:
start_day: int — first day fraud begins
ramp_days: int — days to ramp from 0 → peak
peak_intensity: float — maximum multiplier on legitimate traffic
"""
start = fraud_schedule.get("start_day", 1)
ramp = fraud_schedule.get("ramp_days", 3)
peak = fraud_schedule.get("peak_intensity", 1.0)
if day < start:
return 0.0
# Ramp up
days_active = day - start
if ramp > 0 and days_active < ramp:
base = peak * (days_active / ramp)
else:
base = peak
# Adaptation dampening — fraudster backs off when suspicion rises
stage_mult = {
"normal": 1.0,
"cautious": 0.7,
"covering_tracks": 0.4,
"dark": 0.05,
}.get(adaptation_stage, 1.0)
return base * stage_mult
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