安全 Comparison: Pre-training vs Fine-tuning

"""
Comparative 攻擊面 analysis for pre-訓練 vs 微調.
Quantifies and compares 漏洞 characteristics across phases.
"""
from dataclasses import dataclass, field
from enum import Enum
from typing import Optional
 
 
class TrainingPhase(Enum):
    PRE_TRAINING = "pre_training"
    SFT = "supervised_fine_tuning"
    RLHF = "rlhf"
    DPO = "dpo"
    DEPLOYMENT_FINE_TUNING = "deployment_fine_tuning"
 
 
@dataclass
class PhaseSecurityProfile:
    """安全 profile for a 訓練 phase."""
    phase: TrainingPhase
    data_scale: str
    compute_duration: str
    data_poisoning_difficulty: str
    data_poisoning_impact: str
    supply_chain_risk: str
    insider_threat_risk: str
    safety_alignment_risk: str
    memorization_risk: str
    typical_defenses: list[str] = field(default_factory=list)
 
 
PHASE_PROFILES = [
    PhaseSecurityProfile(
        phase=TrainingPhase.PRE_TRAINING,
        data_scale="1T-15T 符元",
        compute_duration="weeks to months",
        data_poisoning_difficulty="high (need sufficient density in massive corpus)",
        data_poisoning_impact="moderate (diluted by scale)",
        supply_chain_risk="critical (web crawl, third-party datasets)",
        insider_threat_risk="high (long-running, many operators)",
        safety_alignment_risk="low (安全 not yet established)",
        memorization_risk="moderate (repetition-driven)",
        typical_defenses=[
            "Data deduplication",
            "Web content filtering",
            "Dataset provenance tracking",
            "Compute access controls",
        ],
    ),
    PhaseSecurityProfile(
        phase=TrainingPhase.SFT,
        data_scale="10K-1M examples",
        compute_duration="hours to days",
        data_poisoning_difficulty="low (small dataset, concentrated control)",
        data_poisoning_impact="high (direct behavioral influence)",
        supply_chain_risk="medium (curated datasets, human annotators)",
        insider_threat_risk="high (annotator compromise)",
        safety_alignment_risk="high (shapes instruction following)",
        memorization_risk="high (small dataset, many epochs)",
        typical_defenses=[
            "Annotator agreement verification",
            "Data quality scoring",
            "Held-out validation",
            "範例-level auditing",
        ],
    ),
    PhaseSecurityProfile(
        phase=TrainingPhase.RLHF,
        data_scale="50K-500K comparisons",
        compute_duration="days to weeks",
        data_poisoning_difficulty="medium (preference data collection)",
        data_poisoning_impact="critical (directly shapes 安全 behavior)",
        supply_chain_risk="low (internal pipeline)",
        insider_threat_risk="critical (reward model is single point of failure)",
        safety_alignment_risk="critical (primary 安全 mechanism)",
        memorization_risk="low (reward signal, not text)",
        typical_defenses=[
            "Reward model auditing",
            "KL divergence constraints",
            "Multi-annotator agreement",
            "Constitutional AI cross-checks",
        ],
    ),
    PhaseSecurityProfile(
        phase=TrainingPhase.DPO,
        data_scale="10K-100K pairs",
        compute_duration="hours",
        data_poisoning_difficulty="low (small dataset)",
        data_poisoning_impact="critical (direct policy modification)",
        supply_chain_risk="medium (preference data sourcing)",
        insider_threat_risk="high (data curation access)",
        safety_alignment_risk="critical (can undo pre-訓練 安全)",
        memorization_risk="moderate (preference pairs)",
        typical_defenses=[
            "Preference data validation",
            "Implicit reward auditing",
            "Beta parameter 監控",
            "安全 probe 評估",
        ],
    ),
    PhaseSecurityProfile(
        phase=TrainingPhase.DEPLOYMENT_FINE_TUNING,
        data_scale="100-10K examples",
        compute_duration="minutes to hours",
        data_poisoning_difficulty="very low (user-provided data)",
        data_poisoning_impact="critical (user controls the data)",
        supply_chain_risk="critical (user is the 供應鏈)",
        insider_threat_risk="N/A (user is the operator)",
        safety_alignment_risk="critical (Qi et al. 2024 attack vector)",
        memorization_risk="very high (tiny dataset, potential PII)",
        typical_defenses=[
            "安全 評估 gates",
            "Data content filtering",
            "Learning rate limiting",
            "Parameter-efficient methods (LoRA)",
        ],
    ),
]
 
 
def compare_phases(profiles: list[PhaseSecurityProfile]) -> None:
    """Generate a comparative report across 訓練 phases."""
    print("Training Phase 安全 Comparison")
    print("=" * 60)
 
    risk_categories = [
        ("Data Poisoning", lambda p: p.data_poisoning_impact),
        ("Supply Chain", lambda p: p.supply_chain_risk),
        ("安全 Alignment", lambda p: p.safety_alignment_risk),
        ("Memorization", lambda p: p.memorization_risk),
    ]
 
    for category_name, accessor in risk_categories:
        print(f"\n{category_name} Risk:")
        for profile in profiles:
            risk = accessor(profile)
            short_risk = risk.split("(")[0].strip() if "(" in risk else risk
            print(f"  {profile.phase.value:30s}: {short_risk}")
 
 
compare_phases(PHASE_PROFILES)

"""
Quantifying the 微調 安全 漏洞.
Models the asymmetric effort required to establish vs undermine
安全 對齊 across 訓練 phases.
"""
import numpy as np
from dataclasses import dataclass
 
 
@dataclass
class SafetyAlignmentState:
    """Tracks 安全 對齊 across 訓練 phases."""
    phase: str
    safety_score: float  # 0.0 = no 安全, 1.0 = perfect 安全
    compute_cost: float  # Relative compute cost
    data_requirements: int  # Number of examples needed
    vulnerability_window: float  # How easy to undo (0-1)
 
 
def model_safety_across_pipeline(
    pre_training_data_quality: float = 0.5,
    sft_safety_examples: int = 5000,
    rlhf_comparisons: int = 100_000,
    adversarial_ft_examples: int = 100,
) -> list[SafetyAlignmentState]:
    """
    Model how 安全 對齊 evolves across the 訓練 pipeline
    and how vulnerable it is to 對抗性 微調.
 
    Based on findings from Qi et al. 2024 showing that ~100
    對抗性 微調 examples can significantly degrade 安全.
    """
    states = []
 
    # Pre-訓練: baseline 安全 from data curation
    pre_train_safety = 0.3 * pre_training_data_quality
    states.append(SafetyAlignmentState(
        phase="pre_training",
        safety_score=pre_train_safety,
        compute_cost=1000.0,  # Baseline: very expensive
        data_requirements=1_000_000_000,  # Billions of 符元
        vulnerability_window=0.1,  # Hard to attack at scale
    ))
 
    # SFT: 安全 improves with instruction following
    sft_safety = pre_train_safety + 0.3 * min(1.0, sft_safety_examples / 10000)
    states.append(SafetyAlignmentState(
        phase="sft",
        safety_score=sft_safety,
        compute_cost=10.0,
        data_requirements=sft_safety_examples,
        vulnerability_window=0.4,
    ))
 
    # RLHF: major 安全 improvement
    rlhf_safety = sft_safety + 0.4 * min(1.0, rlhf_comparisons / 200_000)
    states.append(SafetyAlignmentState(
        phase="rlhf",
        safety_score=min(0.95, rlhf_safety),
        compute_cost=50.0,
        data_requirements=rlhf_comparisons,
        vulnerability_window=0.3,
    ))
 
    # 對抗性 微調: 安全 degrades dramatically
    # Based on Qi et al. 2024: even 100 examples cause significant degradation
    degradation = 0.5 * min(1.0, adversarial_ft_examples / 200)
    adversarial_safety = max(0.1, rlhf_safety - degradation)
    states.append(SafetyAlignmentState(
        phase="adversarial_fine_tuning",
        safety_score=adversarial_safety,
        compute_cost=0.1,  # Very cheap!
        data_requirements=adversarial_ft_examples,
        vulnerability_window=1.0,  # Trivially accessible
    ))
 
    return states
 
 
# Compare effort to build vs destroy 安全
states = model_safety_across_pipeline()
 
print("安全 Alignment Pipeline:")
print(f"{'Phase':30s} {'安全':>8s} {'Cost':>8s} {'Data':>12s}")
print("-" * 62)
for state in states:
    print(
        f"{state.phase:30s} "
        f"{state.safety_score:8.2f} "
        f"{state.compute_cost:8.1f} "
        f"{state.data_requirements:12,d}"
    )
 
# Highlight the asymmetry
build_cost = sum(s.compute_cost for s in states[:3])
destroy_cost = states[3].compute_cost
print(f"\nTotal cost to BUILD 安全: {build_cost:.1f} compute units")
print(f"Cost to DESTROY 安全: {destroy_cost:.1f} compute units")
print(f"Asymmetry ratio: {build_cost / destroy_cost:.0f}x")

"""
Pre-訓練資料 安全 評估.
Evaluates the 安全 of common pre-訓練資料 sources.
"""
from dataclasses import dataclass, field
 
 
@dataclass
class DataSourceRisk:
    """安全 risk 評估 for a pre-訓練資料 source."""
    source_name: str
    scale: str
    attacker_access: str  # How can 攻擊者 inject content?
    poisoning_persistence: str  # How long does injected content persist?
    detection_difficulty: str
    real_world_examples: list[str] = field(default_factory=list)
 
 
DATA_SOURCE_RISKS = [
    DataSourceRisk(
        source_name="Common Crawl / Web Crawl",
        scale="Petabytes",
        attacker_access="Create/modify web pages, SEO manipulation",
        poisoning_persistence="Until next crawl or domain decommission",
        detection_difficulty="Very hard (vast scale, diverse content)",
        real_world_examples=[
            "SEO spam already pollutes crawl data",
            "Carlini et al. 2024 demonstrated practical web 投毒",
        ],
    ),
    DataSourceRisk(
        source_name="Wikipedia",
        scale="~20GB text",
        attacker_access="Edit pages (moderated, but edit-revert windows exist)",
        poisoning_persistence="Until revert (often hours to days)",
        detection_difficulty="Medium (structured edits, revision history)",
        real_world_examples=[
            "Vandalism is constant despite moderation",
            "Subtle factual modifications can persist for months",
        ],
    ),
    DataSourceRisk(
        source_name="GitHub / Code Repositories",
        scale="Terabytes of code",
        attacker_access="Create repositories, submit pull requests",
        poisoning_persistence="Until repository deletion or PR rejection",
        detection_difficulty="Hard (legitimate code is diverse)",
        real_world_examples=[
            "Typosquatting packages on PyPI/npm",
            "Malicious code in popular repositories",
        ],
    ),
    DataSourceRisk(
        source_name="Books / Academic Papers",
        scale="Terabytes",
        attacker_access="Publish via open-access platforms, arXiv",
        poisoning_persistence="Permanent (published content persists)",
        detection_difficulty="Very hard (appears legitimate)",
        real_world_examples=[
            "Predatory journals publish unreviewed content",
            "arXiv has minimal content filtering",
        ],
    ),
    DataSourceRisk(
        source_name="Synthetic Data (from other models)",
        scale="Variable",
        attacker_access="Compromise teacher model, manipulate generation",
        poisoning_persistence="Permanent in generated dataset",
        detection_difficulty="Very hard (looks like natural text)",
        real_world_examples=[
            "Model collapse from recursive synthetic data",
            "Benchmark contamination from 訓練 on 測試 sets",
        ],
    ),
]
 
 
def prioritize_data_source_defenses(
    risks: list[DataSourceRisk],
) -> list[tuple[str, str]]:
    """Prioritize which data sources need the most 安全 investment."""
    priority_map = {
        "Very hard": 4,
        "Hard": 3,
        "Medium": 2,
        "Easy": 1,
    }
 
    scored = []
    for risk in risks:
        detection_score = priority_map.get(risk.detection_difficulty, 2)
        scored.append((risk.source_name, detection_score, risk))
 
    scored.sort(key=lambda x: x[1], reverse=True)
 
    return [(name, "HIGH_PRIORITY" if score >= 3 else "STANDARD")
            for name, score, _ in scored]
 
 
priorities = prioritize_data_source_defenses(DATA_SOURCE_RISKS)
for source, priority in priorities:
    print(f"  [{priority}] {source}")

"""
微調 安全 degradation simulation.
Models the 安全 impact of different 微調 configurations
based on findings from Qi et al. 2024.
"""
import numpy as np
from dataclasses import dataclass
 
 
@dataclass
class FineTuningConfig:
    """Configuration for a 微調 run."""
    name: str
    num_examples: int
    num_harmful_examples: int
    learning_rate: float
    num_epochs: int
    method: str  # "full", "lora", "prefix_tuning"
 
 
def estimate_safety_degradation(
    config: FineTuningConfig,
    base_safety_score: float = 0.9,
) -> dict:
    """
    Estimate 安全 degradation from 微調.
 
    Model based on Qi et al. 2024 findings:
    - Degradation scales with harmful data fraction
    - Higher learning rates increase degradation
    - Parameter-efficient methods (LoRA) cause less degradation
    - More epochs amplify the effect
    """
    # Harmful data fraction
    harmful_fraction = config.num_harmful_examples / max(config.num_examples, 1)
 
    # Method scaling factor (full 微調 is worst)
    method_factors = {
        "full": 1.0,
        "lora": 0.4,     # LoRA modifies fewer parameters
        "prefix_tuning": 0.3,
    }
    method_factor = method_factors.get(config.method, 1.0)
 
    # Learning rate factor (higher LR = more damage)
    lr_factor = min(2.0, config.learning_rate / 1e-5)
 
    # Epoch factor (diminishing but real)
    epoch_factor = min(3.0, 1.0 + np.log1p(config.num_epochs - 1))
 
    # Compute degradation
    degradation = (
        harmful_fraction
        * method_factor
        * lr_factor
        * epoch_factor
        * 0.8  # Maximum degradation ceiling
    )
 
    final_safety = max(0.05, base_safety_score - degradation)
 
    return {
        "config_name": config.name,
        "base_safety": base_safety_score,
        "estimated_degradation": float(degradation),
        "final_safety": float(final_safety),
        "safety_retained": float(final_safety / base_safety_score),
        "risk_level": (
            "critical" if final_safety < 0.3
            else "high" if final_safety < 0.5
            else "medium" if final_safety < 0.7
            else "low"
        ),
    }
 
 
# Compare different 微調 scenarios
configs = [
    FineTuningConfig("benign_full_ft", 10000, 0, 2e-5, 3, "full"),
    FineTuningConfig("benign_lora", 10000, 0, 2e-4, 3, "lora"),
    FineTuningConfig("100_harmful_full", 10000, 100, 2e-5, 3, "full"),
    FineTuningConfig("100_harmful_lora", 10000, 100, 2e-4, 3, "lora"),
    FineTuningConfig("1000_harmful_full", 10000, 1000, 2e-5, 3, "full"),
    FineTuningConfig("only_harmful", 100, 100, 2e-5, 10, "full"),
    FineTuningConfig("high_lr_harmful", 10000, 100, 2e-4, 3, "full"),
]
 
print(f"{'Config':25s} {'Base':>6s} {'Final':>6s} {'Retained':>10s} {'Risk':>10s}")
print("-" * 62)
for config in configs:
    result = estimate_safety_degradation(config)
    print(
        f"{result['config_name']:25s} "
        f"{result['base_safety']:6.2f} "
        f"{result['final_safety']:6.2f} "
        f"{result['safety_retained']:9.1%} "
        f"{result['risk_level']:>10s}"
    )

"""
微調 安全 preservation framework.
Implements 防禦 to maintain 安全 對齊 during 微調.
"""
import numpy as np
from dataclasses import dataclass, field
 
 
@dataclass
class SafetyGate:
    """A 安全 check that must pass before 微調 completes."""
    name: str
    check_type: str  # "pre", "during", "post"
    blocking: bool  # If True, halt 訓練 on failure
    threshold: float
 
 
SAFETY_GATES = [
    SafetyGate("data_toxicity_scan", "pre", True, 0.01),
    SafetyGate("data_diversity_check", "pre", False, 0.5),
    SafetyGate("loss_spike_monitor", "during", True, 3.0),
    SafetyGate("safety_probe_evaluation", "during", True, 0.7),
    SafetyGate("full_safety_benchmark", "post", True, 0.8),
    SafetyGate("capability_regression", "post", True, 0.9),
    SafetyGate("memorization_test", "post", False, 0.05),
]
 
 
def evaluate_safety_gates(
    gates: list[SafetyGate],
    measurements: dict[str, float],
) -> dict:
    """
    評估 all 安全 gates against measurements.
 
    Returns an overall pass/fail and details 對每個 gate.
    """
    results = {
        "overall_pass": True,
        "blocking_failures": [],
        "warnings": [],
        "details": [],
    }
 
    for gate in gates:
        value = measurements.get(gate.name, 0.0)
 
        # Different gates have different pass conditions
        if gate.check_type == "pre":
            # Pre-checks: value should be below threshold (e.g., toxicity < 1%)
            passed = value <= gate.threshold
        elif gate.check_type == "during":
            # During checks: depends on metric type
            if "spike" in gate.name:
                passed = value <= gate.threshold
            else:
                passed = value >= gate.threshold
        else:
            # Post checks: value should exceed threshold
            passed = value >= gate.threshold
 
        detail = {
            "gate": gate.name,
            "type": gate.check_type,
            "value": value,
            "threshold": gate.threshold,
            "passed": passed,
            "blocking": gate.blocking,
        }
        results["details"].append(detail)
 
        if not passed:
            if gate.blocking:
                results["overall_pass"] = False
                results["blocking_failures"].append(gate.name)
            else:
                results["warnings"].append(gate.name)
 
    return results
 
 
# Demonstration: safe 微調 run
safe_measurements = {
    "data_toxicity_scan": 0.005,      # 0.5% toxicity (below 1% threshold)
    "data_diversity_check": 0.7,       # Good diversity
    "loss_spike_monitor": 1.5,         # Normal loss variation
    "safety_probe_evaluation": 0.85,   # 安全 maintained
    "full_safety_benchmark": 0.88,     # Above 80% threshold
    "capability_regression": 0.95,     # Minimal regression
    "memorization_test": 0.02,         # Low memorization
}
 
safe_result = evaluate_safety_gates(SAFETY_GATES, safe_measurements)
print(f"Safe run: pass={safe_result['overall_pass']}")
print(f"  Warnings: {safe_result['warnings']}")
 
# Demonstration: unsafe 微調 run
unsafe_measurements = {
    "data_toxicity_scan": 0.005,
    "data_diversity_check": 0.3,       # Low diversity (warning)
    "loss_spike_monitor": 1.2,
    "safety_probe_evaluation": 0.45,   # 安全 degraded!
    "full_safety_benchmark": 0.55,     # Below threshold!
    "capability_regression": 0.92,
    "memorization_test": 0.08,         # High memorization (warning)
}
 
unsafe_result = evaluate_safety_gates(SAFETY_GATES, unsafe_measurements)
print(f"\nUnsafe run: pass={unsafe_result['overall_pass']}")
print(f"  Blocking failures: {unsafe_result['blocking_failures']}")
print(f"  Warnings: {unsafe_result['warnings']}")