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使用对抗性攻击破坏模型

通过执行“红队测试”(Red Teaming)压力测试,学习对抗鲁棒性的原理。你将使用标准诊断工具(FGSM 和 PGD)来识别模型的漏洞,以便进行修复。

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使用对抗性攻击破坏模型

通过执行“红队测试”(Red Teaming)压力测试,学习对抗鲁棒性的原理。你将使用标准诊断工具(FGSM 和 PGD)来识别模型的漏洞,以便进行修复。

AdversarialImage = OriginalImage + \epsilon \times sign(\nabla_x Loss)

1# --- Setup and Model Load --- 2device = torch.device("cuda" if torch.cuda.is_available() else "cpu") 3model = models.resnet50(weights=models.ResNet50_Weights.IMAGENET1K_V1).to(device) 4model.eval() 5 6# --- Image Preparation (Assumes image path is valid) --- 7image_path = "../Giant_Panda_in_Beijing_Zoo_1.jpeg" 8#... (Image loading and preprocessing code omitted for brevity) 9 10# Create the input tensor, enable gradient tracking for the attack 11input_tensor = preprocess(img).unsqueeze(0).to(device).requires_grad_(True) 12labels = get_imagenet_labels() # Load the class names 13 14# --- Initial Prediction (Before Attack) --- 15pred_initial = model(input_tensor) 16probabilities_initial = F.softmax(pred_initial, dim=1) 17top_prob_initial, top_catid_initial = torch.max(probabilities_initial, 1) 18 19original_confidence = top_prob_initial.item() 20target_id_for_attack = top_catid_initial.item() 21original_label = labels.get(target_id_for_attack, f"ID {target_id_for_attack} (Unknown)") 22 23print("\n--- Model Prediction: BEFORE ATTACK ---") 24print(f"Top Prediction: {original_label} (ID: {target_id_for_attack})") 25print(f"Confidence: {original_confidence*100:.2f}%")
1def fgsm_attack(image, epsilon, model, target_id): 2 """Performs FGSM attack, targets the original prediction to maximize loss.""" 3 output = model(image) 4 5 # Calculate Loss against the correct label (the one we want to maximize error for) 6 target = torch.tensor([target_id]).to(image.device) 7 loss = nn.CrossEntropyLoss()(output, target) 8 9 # Backward Pass: Calculate the Gradient of the Loss w.r.t. the Input 10 model.zero_grad() 11 loss.backward() 12 13 # Collect the Gradient and take the sign() to get the Direction 14 data_grad = image.grad.data 15 sign_data_grad = data_grad.sign() 16 17 # Perturb the Image (Original + Epsilon * Direction) 18 perturbed_image = image + epsilon * sign_data_grad 19 20 # Clip to maintain valid image range 21 perturbed_image = torch.clamp(perturbed_image, 0, 1) 22 23 return perturbed_image
1# --- Execute FGSM Attack --- 2epsilon = 0.05 3adv_image = fgsm_attack(input_tensor, epsilon, model, target_id_for_attack) 4 5# --- Adversarial Prediction (After Attack) --- 6new_pred = model(adv_image) 7probabilities_adv = F.softmax(new_pred, dim=1) 8 9top_pred_conf_adv, top_pred_idx_adv = torch.max(probabilities_adv, 1) 10top_pred_idx_adv = top_pred_idx_adv.item() 11top_pred_conf_adv = top_pred_conf_adv.item() 12 13adv_label = labels.get(top_pred_idx_adv, f"ID {top_pred_idx_adv} (Unknown)") 14attack_success = '✅ SUCCESS' if top_pred_idx_adv!= target_id_for_attack else '❌ FAIL' 15 16print("\n--- Model Prediction: AFTER ATTACK ---") 17print(f"Attack Epsilon: {epsilon}") 18print(f"New Prediction: {adv_label} (ID: {top_pred_idx_adv})") 19print(f"Confidence: {top_pred_conf_adv*100:.2f}%") 20print(f"Result: {attack_success}")
...
1import torch 2import torch.nn as nn 3import torchvision.models as models 4import torchvision.transforms as transforms 5from PIL import Image 6import matplotlib.pyplot as plt 7import torch.nn.functional as F 8import numpy as np 9import requests 10 11# --- 0. Helper Functions and Data --- 12 13def get_imagenet_labels(): 14 """ 15 Downloads the full 1000 ImageNet class labels from the PyTorch Hub URL 16 and returns them as a dictionary mapping index (int) to label (str). 17 """ 18 class_index_url = "https://raw.githubusercontent.com/pytorch/hub/master/imagenet_classes.txt" 19 20 try: 21 # Use requests to download the file contents 22 response = requests.get(class_index_url) 23 response.raise_for_status() # Check for HTTP errors (404, 403, etc.) 24 25 # Read the raw text content 26 text_content = response.text 27 28 # Split the content into lines 29 # Each line is the class name, starting from index 0 30 labels_list = text_content.strip().split('\n') 31 32 # Create a dictionary mapping index (0-999) to the label 33 labels_dict = {i: label for i, label in enumerate(labels_list)} 34 35 return labels_dict 36 37 except requests.exceptions.RequestException as e: 38 print(f"❌ Error fetching ImageNet labels from URL: {e}") 39 # Fallback to a dictionary with the known Panda label to allow execution to continue 40 return {388: 'giant panda, panda, panda bear, Ailuropoda melanoleuca', 41 0: 'tench', 42 999: 'toilet tissue'} 43 except Exception as e: 44 print(f"❌ An unexpected error occurred while processing labels: {e}") 45 return {} 46 47def denormalize(tensor): 48 """Reverses the ImageNet normalization for visualization.""" 49 # Standard ImageNet mean and std 50 mean = torch.tensor([0.485, 0.456, 0.406]).view(1, 3, 1, 1).to(tensor.device) 51 std = torch.tensor([0.229, 0.224, 0.225]).view(1, 3, 1, 1).to(tensor.device) 52 53 # Reverse the normalization: (tensor * std) + mean 54 tensor = tensor * std + mean 55 56 # Clip the values to [0, 1] range and convert to CPU numpy array 57 return torch.clamp(tensor, 0, 1).squeeze().permute(1, 2, 0).cpu().numpy() 58 59def fgsm_attack(image, epsilon, model, target_id): 60 """Performs FGSM attack, targets the original prediction to maximize loss.""" 61 output = model(image) 62 63 # Create a tensor with the single target class ID 64 target = torch.tensor([target_id]).to(image.device) 65 loss = nn.CrossEntropyLoss()(output, target) 66 67 model.zero_grad() 68 loss.backward() 69 70 data_grad = image.grad.data 71 sign_data_grad = data_grad.sign() 72 73 # Create the perturbed image 74 perturbed_image = image + epsilon * sign_data_grad 75 76 # Clip to maintain valid image range [0, 1] 77 perturbed_image = torch.clamp(perturbed_image, 0, 1) 78 79 return perturbed_image 80 81# --- 1. Setup and Model Load --- 82device = torch.device("cuda" if torch.cuda.is_available() else "cpu") 83# Use the modern weights= parameter to avoid UserWarnings 84model = models.resnet50(weights=models.ResNet50_Weights.IMAGENET1K_V1).to(device) 85model.eval() 86 87# --- 2. Image Preparation --- 88image_path = "/udata/G4GvJEvBL2W/Giant_Panda_in_Beijing_Zoo_1.jpeg" 89try: 90 img = Image.open(image_path).convert("RGB") 91 print(f"✅ Successfully loaded the image: {image_path}") 92except: 93 print(f"❌ Error: Could not load the image. Check file path.") 94 exit() 95 96preprocess = transforms.Compose([ 97 transforms.Resize(256), 98 transforms.CenterCrop(224), 99 transforms.ToTensor(), 100 transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]), 101]) 102 103# Create the input tensor, enable gradient tracking for the attack 104input_tensor = preprocess(img).unsqueeze(0).to(device).requires_grad_(True) 105labels = get_imagenet_labels() # Load the class names 106 107# --- 3. Initial Prediction (Before Attack) --- 108pred_initial = model(input_tensor) 109probabilities_initial = F.softmax(pred_initial, dim=1) 110top_prob_initial, top_catid_initial = torch.max(probabilities_initial, 1) 111 112original_confidence = top_prob_initial.item() 113target_id_for_attack = top_catid_initial.item() # Should be 388 (Panda) 114original_label = labels.get(target_id_for_attack, f"ID {target_id_for_attack} (Unknown)") 115 116print("\n--- Model Prediction: BEFORE ATTACK ---") 117print(f"Top Prediction: {original_label} (ID: {target_id_for_attack})") 118print(f"Confidence: {original_confidence*100:.2f}%") 119 120# --- 4. Execute FGSM Attack --- 121epsilon = 0.05 # The strength of the noise 122adv_image = fgsm_attack(input_tensor, epsilon, model, target_id_for_attack) 123 124# --- 5. Adversarial Prediction (After Attack) --- 125new_pred = model(adv_image) 126probabilities_adv = F.softmax(new_pred, dim=1) 127 128# Get the new top prediction and its confidence 129top_pred_conf_adv, top_pred_idx_adv = torch.max(probabilities_adv, 1) 130top_pred_idx_adv = top_pred_idx_adv.item() 131top_pred_conf_adv = top_pred_conf_adv.item() 132 133adv_label = labels.get(top_pred_idx_adv, f"ID {top_pred_idx_adv} (Unknown)") 134attack_success = '✅ SUCCESS' if top_pred_idx_adv != target_id_for_attack else '❌ FAIL' 135 136print("\n--- Model Prediction: AFTER ATTACK ---") 137print(f"Attack Epsilon: {epsilon}") 138print(f"New Prediction: {adv_label} (ID: {top_pred_idx_adv})") 139print(f"Confidence: {top_pred_conf_adv*100:.2f}%") 140print(f"Result: {attack_success}") 141 142# --- 6. Visualization --- 143original_denorm = denormalize(input_tensor.data) 144adv_denorm = denormalize(adv_image.data) 145 146# Calculate the perturbation (noise) 147perturbation = adv_denorm - original_denorm 148 149# Setup plot for 3 images 150fig, ax = plt.subplots(1, 3, figsize=(18, 6)) 151 152# Plot 1: Original Image 153ax[0].imshow(original_denorm) 154ax[0].set_title(f"Original Image\nPred: {original_label}\nConf: {original_confidence*100:.1f}%", fontsize=10) 155ax[0].axis('off') 156 157# Plot 2: Perturbation (Noise) 158# We scale the perturbation to make the subtle noise visible 159im = ax[1].imshow(perturbation * 10, cmap='bwr', vmin=-1, vmax=1) 160ax[1].set_title(r"Perturbation (Noise $\eta$) x10" "\n(Imperceptible to Human Eye)", fontsize=10) 161ax[1].axis('off') 162 163# Plot 3: Adversarial Image 164ax[2].imshow(adv_denorm) 165ax[2].set_title(f"Adversarial Image\nPred: {adv_label}\nConf: {top_pred_conf_adv*100:.1f}%", fontsize=10, color='red') 166ax[2].axis('off') 167 168plt.tight_layout() 169filename = "panda.png" 170plt.savefig(filename, dpi=800, bbox_inches='tight') 171plt.show()
1def pgd_attack(model, image, label, epsilon=0.07, alpha=0.01, num_steps=40): 2 """ 3 Projected Gradient Descent (PGD) Attack: Iteratively finds the worst-case noise. 4 """ 5 # Detach to create a new tensor that we can modify 6 image = image.clone().detach() 7 adversarial_image = image.clone().detach() 8 9 # PGD starts with random noise for a better search of max error (the "worst-case") 10 random_noise = torch.rand_like(image).uniform_(-epsilon, epsilon) 11 adversarial_image = torch.clamp(image + random_noise, 0, 1) 12 13 # --- The Iterative Loop starts here --- 14 for i in range(num_steps): 15 adversarial_image.requires_grad = True 16 17 # A. Forward pass, Loss Calculation, and Backward Pass (omitted for brevity) 18 # B. Gradient Step (omitted for brevity) 19 # C. Projection (omitted for brevity) 20 21 return adversarial_image

Gradient step and move

1#... inside the 'for i in range(num_steps):' loop... 2 3 # A. Forward pass and Loss Calculation 4 output = model(adversarial_image) 5 target = torch.tensor([label]).to(image.device) 6 loss = nn.CrossEntropyLoss()(output, target) 7 8 # B. Backward Pass (Calculate the Gradient) 9 model.zero_grad() 10 loss.backward() 11 12 # C. Take a step (step size is alpha) 13 with torch.no_grad(): 14 # Calculate the direction of max error and move the image in that direction 15 perturbation = alpha * adversarial_image.grad.sign() 16 adversarial_image += perturbation 17 18 #... Projection step follows...
1#... continuation of the 'with torch.no_grad():' block... 2 3 # D. PROJECT (Clip the noise back into the epsilon ball) 4 # 1. Calculate the difference (delta) from the original clean image 5 delta = adversarial_image - image 6 # 2. Clip that difference so it stays within [-epsilon, epsilon] 7 delta = torch.clamp(delta, min=-epsilon, max=epsilon) 8 # 3. Add the clipped noise back to the original image 9 adversarial_image = torch.clamp(image + delta, min=0, max=1)
1# --- EXECUTE THE PGD TEST --- 2 3epsilon_pgd = 0.07 4adv_image_pgd = pgd_attack(model, input_tensor, target_id_for_attack, epsilon=epsilon_pgd, alpha=0.01) 5 6# Adversarial Prediction (After PGD Attack) 7pred_pgd = model(adv_image_pgd) 8probabilities_pgd = F.softmax(pred_pgd, dim=1) 9 10# Get the new top prediction and its confidence 11top_pred_conf_pgd, top_pred_idx_pgd = torch.max(probabilities_pgd, 1) 12adv_label_pgd = labels.get(top_pred_idx_pgd.item(), f"ID {top_pred_idx_pgd.item()} (Unknown)") 13attack_success_pgd = '✅ SUCCESS' if top_pred_idx_pgd.item()!= target_id_for_attack else '❌ FAIL' 14 15print("\n--- Model Prediction: AFTER PGD ATTACK (Worst-Case Test) ---") 16print(f"Attack Epsilon: {epsilon_pgd}") 17print(f"New Prediction: {adv_label_pgd} (ID: {top_pred_idx_pgd.item()})") 18print(f"Confidence: {top_pred_conf_pgd.item()*100:.2f}%") 19print(f"Result: {attack_success_pgd} (PGD is the 'Gold Standard' for breaking robustness)")
1import torch 2import torch.nn as nn 3import torchvision.models as models 4import torchvision.transforms as transforms 5from PIL import Image 6import matplotlib.pyplot as plt 7import torch.nn.functional as F 8import numpy as np 9import requests # Required for downloading class names 10 11# --- 0. Helper Functions and Data --- 12 13def get_imagenet_labels(): 14 """Downloads ImageNet class labels for human-readable output.""" 15 class_index_url = "https://raw.githubusercontent.com/pytorch/hub/master/imagenet_classes.txt" 16 try: 17 response = requests.get(class_index_url) 18 response.raise_for_status() 19 labels_list = response.text.strip().split('\n') 20 labels_dict = {i: label for i, label in enumerate(labels_list)} 21 print("✅ Successfully fetched all 1000 ImageNet labels.") 22 return labels_dict 23 except requests.exceptions.RequestException as e: 24 print(f"❌ Error fetching ImageNet labels from URL: {e}") 25 # Fallback for demonstration 26 return {388: 'giant panda, panda', 346: 'cougar, puma, catamount', 0: 'tench', 999: 'toilet tissue'} 27 except Exception as e: 28 print(f"❌ An unexpected error occurred while processing labels: {e}") 29 return {} 30 31def denormalize(tensor): 32 """Reverses the ImageNet normalization for visualization.""" 33 # Standard ImageNet mean and std 34 mean = torch.tensor([0.485, 0.456, 0.406]).view(1, 3, 1, 1).to(tensor.device) 35 std = torch.tensor([0.229, 0.224, 0.225]).view(1, 3, 1, 1).to(tensor.device) 36 37 # Reverse the normalization: (tensor * std) + mean 38 tensor = tensor * std + mean 39 40 # Clip the values to [0, 1] range and convert to CPU numpy array 41 return torch.clamp(tensor, 0, 1).squeeze().permute(1, 2, 0).cpu().numpy() 42 43def pgd_attack(model, image, label, epsilon=0.07, alpha=0.01, num_steps=40): 44 """ 45 Projected Gradient Descent (PGD) Attack: Iteratively finds the worst-case noise. 46 """ 47 # Detach and clone to ensure clean tensor operations 48 image = image.clone().detach() 49 adversarial_image = image.clone().detach() 50 51 # Start with random noise within the epsilon boundary for better robustness 52 random_noise = torch.rand_like(image).uniform_(-epsilon, epsilon) 53 # Clip the initial image + noise to the valid [0, 1] range 54 adversarial_image = torch.clamp(image + random_noise, 0, 1) 55 56 for i in range(num_steps): 57 adversarial_image.requires_grad = True 58 59 # A. Forward pass and Loss Calculation 60 output = model(adversarial_image) 61 target = torch.tensor([label]).to(image.device) 62 # Loss calculated against the true label (untargeted attack: maximize loss) 63 loss = nn.CrossEntropyLoss()(output, target) 64 65 # B. Backward Pass: Calculate the Gradient 66 model.zero_grad() 67 loss.backward() 68 69 # C. Take a step (step size is alpha) 70 with torch.no_grad(): 71 # Get the sign of the gradient (direction of maximum increase in loss) 72 perturbation = alpha * adversarial_image.grad.sign() 73 # Step in the direction of the gradient 74 adversarial_image += perturbation 75 76 # D. PROJECTION/CLIPPING (Ensures noise stays within epsilon of original image) 77 # Calculate difference (delta) from the original clean image 78 delta = adversarial_image - image 79 # Project delta back into the L-infinity ball (max change of epsilon) 80 delta = torch.clamp(delta, min=-epsilon, max=epsilon) 81 # Reconstruct the adversarial image and clip to valid pixel range [0, 1] 82 adversarial_image = torch.clamp(image + delta, min=0, max=1) 83 84 return adversarial_image 85 86 87# --- 1. Setup and Model Load --- 88device = torch.device("cuda" if torch.cuda.is_available() else "cpu") 89# Load ResNet-50 model weights pre-trained on ImageNet 90model = models.resnet50(weights=models.ResNet50_Weights.IMAGENET1K_V1).to(device) 91model.eval() 92 93# --- 2. Image Preparation (Panda Example) --- 94image_path = "/content/Giant_Panda_in_Beijing_Zoo_1.jpeg" 95try: 96 img = Image.open(image_path).convert("RGB") 97 print(f"✅ Successfully loaded the image: {image_path}") 98except: 99 print(f"❌ Error: Could not load the image. Please verify the file path.") 100 exit() 101 102# FIX: Corrected transforms.Compose list 103preprocess = transforms.Compose([ 104 transforms.Resize(256), 105 transforms.CenterCrop(224), 106 transforms.ToTensor(), 107 transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225]), 108]) 109 110# Create the input tensor and enable gradient tracking 111input_tensor = preprocess(img).unsqueeze(0).to(device).requires_grad_(True) 112labels = get_imagenet_labels() 113 114# --- 3. Initial Prediction (To define the target for the attack) --- 115pred_initial = model(input_tensor) 116probabilities_initial = F.softmax(pred_initial, dim=1) 117top_prob_initial, top_catid_initial = torch.max(probabilities_initial, 1) 118 119original_confidence = top_prob_initial.item() 120target_id_for_attack = top_catid_initial.item() 121original_label = labels.get(target_id_for_attack, f"ID {target_id_for_attack} (Unknown)") 122 123print("\n--- Model Prediction: INITIAL BASELINE ---") 124print(f"Top Prediction: {original_label} (ID: {target_id_for_attack})") 125print(f"Confidence: {original_confidence*100:.2f}%") 126 127# --- 4. EXECUTE THE PGD ATTACK --- 128epsilon_pgd = 0.07 129adv_image_pgd = pgd_attack(model, input_tensor, target_id_for_attack, epsilon=epsilon_pgd, alpha=0.01) 130 131# --- 5. Adversarial Prediction (After PGD Attack) --- 132pred_pgd = model(adv_image_pgd) 133probabilities_pgd = F.softmax(pred_pgd, dim=1) 134 135top_pred_conf_pgd, top_pred_idx_pgd = torch.max(probabilities_pgd, 1) 136adv_label_pgd = labels.get(top_pred_idx_pgd.item(), f"ID {top_pred_idx_pgd.item()} (Unknown)") 137attack_success_pgd = '✅ SUCCESS' if top_pred_idx_pgd.item()!= target_id_for_attack else '❌ FAIL' 138 139print("\n--- Model Prediction: AFTER PGD ATTACK (Worst-Case Test) ---") 140print(f"Attack Epsilon: {epsilon_pgd}") 141print(f"New Prediction: {adv_label_pgd} (ID: {top_pred_idx_pgd.item()})") 142print(f"Confidence: {top_pred_conf_pgd.item()*100:.2f}%") 143print(f"Result: {attack_success_pgd}") 144 145# --- 6. Visualization and Saving --- 146original_denorm = denormalize(input_tensor.data) 147adv_denorm_pgd = denormalize(adv_image_pgd.data) 148 149perturbation_pgd = adv_denorm_pgd - original_denorm 150 151# FIX: Corrected indexing: ax is an array of 3 axes 152fig, ax = plt.subplots(1, 3, figsize=(18, 6)) 153 154# Plot 1: Original Image 155ax[0].imshow(original_denorm) 156ax[0].set_title(f"Original Image\nPred: {original_label}\nConf: {original_confidence*100:.1f}%", fontsize=10) 157ax[0].axis('off') 158 159# Plot 2: Perturbation (Noise) 160# Use raw string for title to avoid SyntaxWarning with \n 161im = ax[1].imshow(perturbation_pgd * 10, cmap='bwr', vmin=-1, vmax=1) 162ax[1].set_title(r"PGD Perturbation (Noise $\eta$) x10" f"\nEpsilon={epsilon_pgd}", fontsize=10) 163ax[1].axis('off') 164 165# Plot 3: Adversarial Image 166ax[2].imshow(adv_denorm_pgd) 167ax[2].set_title(f"PGD Attacked Image\nNew Pred: {adv_label_pgd}\nConf: {top_pred_conf_pgd.item()*100:.1f}%", fontsize=10, color='red') 168ax[2].axis('off') 169 170plt.tight_layout() 171filename = "pgd_panda_attack.png" 172plt.savefig(filename, dpi=800, bbox_inches='tight') 173print(f"\nFigure saved successfully as: {filename}") 174plt.show()
...

MetricInitial BaselinePGD Worst-Case Result
Top Predictiongiant panda (ID: 388)bison (ID: 347)
Confidence85.16%100.00%
ConclusionHigh accuracyProfound robustness failure

AI Safety Case Excerpt (Part 1)

Module: Robustness and adversarial defense

This section documents the results of the Red Team evaluation conducted to test the system's resilience against worst-case, imperceptible input perturbations. Robustness is a core pillar of AI Safety, directly mitigating the risk of system Malfunctions (accidents) in deployment.

Artifact IDDateTest TypeBudget (ϵ)Result
ROBUST-PGD-001Projected Gradient Descent (PGD)0.07 (L-infinity)Failure
Claim: Lack of sufficient adversarial robustness

Argument: The model lacks the necessary robustness to operate safely in any real-world environment where inputs may be noisy, perturbed, or unintentionally misleading. The system is fundamentally brittle and susceptible to catastrophic misclassification by exploiting mathematical flaws, even when the input image is visually unchanged for a human observer.

Evidence: PGD worst-case failure data

The PGD iterative stress test (the "Gold Standard" for robustness) confirms a profound structural weakness in the model, demonstrating a confident failure mode that must be addressed before deployment.

MetricBaseline (Clean Image)PGD Attacked Image (ϵ=0.07)
Top Predictiongiant panda (ID: 388)bison (ID: 347)
Confidence85.16%100.00%
Failure ModeHigh AccuracyConfident, Decisive Misclassification

The PGD algorithm successfully maximized the loss function within the allowed budget (ϵ=0.07\epsilon=0.07). The model not only failed to maintain its classification but also shifted its confidence to an absolute certainty (100.00100.00%) in an incorrect class (bison). This demonstrates that the model relies on fragile, easily manipulated mathematical patterns and is vulnerable to systemic failure, which is a clear deficiency in the model's safety profile.

Mitigation: Required defense strategy

The demonstrated failure cannot be resolved with simple input filters or output monitoring. The lack of robustness is an intrinsic flaw that must be addressed at the model level.

  • Required mitigation: Implement a robust fine-tuning technique, specifically adversarial training.
  • Action plan: The model must be retrained using the set of adversarial examples generated during this PGD Red Team exercise. The new training loop will force the model to correctly classify these worst-case inputs, effectively strengthening the model's internal weights and significantly expanding its safe operational range (improving robustness).

AI Safety Case Excerpt (Part 1)

Module: Robustness and adversarial defense

This section documents the results of the Red Team evaluation conducted to test the system’s resilience against worst-case, imperceptible input perturbations. Robustness is a core pillar of AI Safety, directly mitigating the risk of system Malfunctions (accidents) in deployment.

Artifact IDDateTest TypeBudget (ϵ)Result
ROBUST-PGD-001Projected Gradient Descent (PGD)0.07 (L-infinity)Failure
Claim: Lack of sufficient adversarial robustness

Argument: The model lacks the necessary robustness to operate safely in any real-world environment where inputs may be noisy, perturbed, or unintentionally misleading. The system is fundamentally brittle and susceptible to catastrophic misclassification by exploiting mathematical flaws, even when the input image is visually unchanged for a human observer.

Evidence: PGD worst-case failure data

The PGD iterative stress test (the “Gold Standard” for robustness) confirms a profound structural weakness in the model, demonstrating a confident failure mode that must be addressed before deployment.

MetricBaseline (Clean Image)PGD Attacked Image (ϵ=0.07)
Top Predictiongiant panda (ID: 388)bison (ID: 347)
Confidence85.16%100.00%
Failure ModeHigh AccuracyConfident, Decisive Misclassification

The PGD algorithm successfully maximized the loss function within the allowed budget (ϵ=0.07\epsilon=0.07). The model not only failed to maintain its classification but also shifted its confidence to an absolute certainty (100.00100.00%) in an incorrect class (bison). This demonstrates that the model relies on fragile, easily manipulated mathematical patterns and is vulnerable to systemic failure, which is a clear deficiency in the model’s safety profile.

Mitigation: Required defense strategy

The demonstrated failure cannot be resolved with simple input filters or output monitoring. The lack of robustness is an intrinsic flaw that must be addressed at the model level.

  • Required mitigation: Implement a robust fine-tuning technique, specifically adversarial training.
  • Action plan: The model must be retrained using the set of adversarial examples generated during this PGD Red Team exercise. The new training loop will force the model to correctly classify these worst-case inputs, effectively strengthening the model’s internal weights and significantly expanding its safe operational range (improving robustness).

构建安全 AI 系统的基础

使用 LIME 和 SHAP 检查不透明模型