Deep learning models have revolutionized the field of artificial intelligence, but they also have a major weakness: their susceptibility to adversarial attacks. These attacks can be designed to manipulate the model's predictions by adding small, imperceptible changes to the input data.
Adversarial attacks can be particularly devastating in applications where model accuracy is crucial, such as image classification, object detection, and natural language processing. For instance, a study found that a carefully crafted adversarial image can cause a state-of-the-art image classifier to misclassify a stop sign as a speed limit sign.
To counter this threat, researchers have been working on developing deep learning models that are resistant to adversarial attacks. One approach is to use adversarial training, which involves training the model on a mix of normal and adversarial examples. This can help the model learn to recognize and reject adversarial inputs.
By incorporating adversarial training into the development process, researchers have been able to create models that are significantly more robust to adversarial attacks. For example, a study found that a model trained with adversarial examples was able to correctly classify images even when attacked with a sophisticated adversarial technique.
For another approach, see: Hidden Layers in Neural Networks Code Examples Tensorflow
Defending Against Attacks
One way to defend against powerful white-box adversarial attacks is through adversarial training. This process involves training a model to be robust against attacks by deliberately introducing perturbations to its inputs.
Adversarial training can be achieved through a method called projected gradient descent (PGD) attack. This attack works by iteratively perturbing the input to the model to maximize the model's error.
By training a model to be robust against PGD attacks, you can create models that are more resistant to adversarial attacks.
Suggestion: Ddos Attack
Benefits and History
Deep learning models resistant to adversarial attacks have some unexpected benefits. Adversarial training of an MNIST classifier has been found to produce models that can smoothly interpolate between classes using large-epsilon adversarial examples. This means that the model can produce images that are clearly of the desired class, even when the input is heavily perturbed.
These models also have sparse weights, which are considered useful for their own sake as they're more interpretable and are more amenable to pruning and hence model size reductions. The L∞ model, in particular, has very sparse weights, with most filters being zeros and the non-zero filters containing only one non-zero weight.
The history of adversarial attacks on deep learning models is a story of gradual understanding of the vulnerabilities of these models. Researchers have been experimenting with machine-learning spam filters since 2004, and by 2012, it was clear that deep neural networks could be fooled by adversaries using gradient-based attacks.
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Benefits of a Robust Model
A robust model has some amazing benefits that go beyond just being able to withstand attacks. One of the most interesting benefits is the ability to smoothly interpolate between classes using large-epsilon adversarial examples.
This means that a robust model can create images that are clearly of the desired class, even when given a large amount of noise. This is because the gradients of the robust model in the input space align well with human perception, making it possible to produce plausible images.
The L² trained model is particularly good at this, producing images that are remarkably similar to the desired class, even with large amounts of noise. This is in contrast to non-robust models, which produce garbage images that only bear a slight resemblance to the desired classes.
Another benefit of a robust model is that it can produce very sparse weights, which are useful for their own sake as they're more interpretable and amenable to pruning and model size reductions. The L∞ model, in particular, has most of its filters as zeros, with the non-zero filters containing only one non-zero weight.
This means that the non-zero filters act as thresholding filters, which can help to destroy small perturbations and make the model more robust to attacks. This is a well-known adversarial defense, and it's impressive that adversarial training can cause the model to learn this independently.
Here are some of the benefits of a robust model:
- Smooth interpolation between classes using large-epsilon adversarial examples
- Production of very sparse weights
- Improved robustness to attacks
- Destruction of small perturbations through thresholding filters
These benefits make a robust model a valuable tool for a wide range of applications, from image classification to natural language processing.
History
The history of spam filters is a fascinating story of cat and mouse between spammers and researchers. In 2004, John Graham-Cumming showed that a machine-learning spam filter could be used to defeat another machine-learning spam filter by automatically learning which words to add to a spam email to get the email classified as not spam.
Spammers quickly adapted to this tactic by inserting "good words" into their spam emails to evade linear classifiers. This was first noted in 2004 by Nilesh Dalvi and others, who observed that simple "evasion attacks" could defeat these filters.
As researchers continued to develop more advanced spam filters, spammers found new ways to evade them. In 2006, a study outlined a broad taxonomy of attacks that could be used against machine-learning models. These attacks included gradient-based attacks, which were later used to fool deep neural networks.
In 2012, deep neural networks began to dominate computer vision problems, but they were not immune to attacks. Christian Szegedy and others demonstrated in 2014 that deep neural networks could be fooled by adversaries using a gradient-based attack to craft adversarial perturbations.
Here are some key events in the history of spam filters:
- 2004: John Graham-Cumming shows that a machine-learning spam filter can be used to defeat another machine-learning spam filter.
- 2004: Nilesh Dalvi and others note that linear classifiers can be defeated by simple "evasion attacks".
- 2006: A study outlines a broad taxonomy of attacks that can be used against machine-learning models.
- 2012: Deep neural networks begin to dominate computer vision problems.
- 2014: Christian Szegedy and others demonstrate that deep neural networks can be fooled by adversaries.
Attack Types and Modalities
Adversarial attacks come in many forms, each with its own unique characteristics. There are a large variety of different adversarial attacks that can be used against machine learning systems.
Some of the most common attack types include Adversarial Examples, Trojan Attacks / Backdoor Attacks, Model Inversion, and Membership Inference. These attacks can be used against both deep learning systems and traditional machine learning models like SVMs and linear regression.
Additional reading: Learning Systems in Machine Learning
Attacks can be categorized along three primary axes: influence on the classifier, security violation, and specificity. This taxonomy has been extended into a more comprehensive threat model that allows explicit assumptions about the adversary's goal, knowledge of the attacked system, and capability of manipulating the input data/system components.
Evasion attacks are a type of attack that exploit the imperfection of a trained model. They can be generally split into two different categories: black box attacks and white box attacks.
Attack Modalities
Adversarial attacks come in many forms, each with its own unique characteristics.
One type of attack is the Adversarial Example, which can be used against both deep learning systems and traditional machine learning models like SVMs and linear regression.
Trojan Attacks, also known as Backdoor Attacks, are another type of attack that can be used against machine learning systems.
Model Inversion is a type of attack that can be used to extract sensitive information from a trained model.
Membership Inference is a type of attack that can be used to determine whether a specific data point was used to train a model or not.
On a similar theme: Evasion Attack Example
Taxonomy
Machine learning algorithms can be vulnerable to attacks that disrupt their classification phase, which may be preceded by an exploration phase to identify vulnerabilities. The attacker's capabilities might be restricted by the presence of data manipulation constraints.
There are three primary axes to categorize attacks against supervised machine learning algorithms: influence on the classifier, security violation, and specificity.
A targeted attack attempts to allow a specific intrusion/disruption, while an indiscriminate attack creates general mayhem.
Attacks can influence the classifier by disrupting the classification phase, and they can also supply malicious data that gets classified as legitimate. Malicious data supplied during training can cause legitimate data to be rejected after training.
Here's a breakdown of the three primary axes:
Byzantine Attacks
In distributed learning, some participants may deviate from their expected behavior to harm the central server's model or bias algorithms towards certain behaviors. This can happen when edge devices collaborate with a central server, sending gradients or model parameters.
Machine learning models are vulnerable to attacks on the machine they're trained on, especially if the training is performed on a single machine. This is because the machine is a single point of failure.
The machine owner can even insert undetectable backdoors, which can be a significant threat to the model's integrity. This highlights the importance of robust security measures in machine learning.
Robust gradient aggregation rules are currently the leading solution to make learning algorithms provably resilient to a minority of malicious participants. However, these rules may not work as well when the data across participants has a non-iid distribution.
In the context of heterogeneous honest participants, such as users with different consumption habits or writing styles, there are provable impossibility theorems on what any robust learning algorithm can guarantee.
Black Box Attacks
Black Box Attacks are a type of evasion attack that doesn't require any information about the model's internal workings. This makes them particularly challenging to defend against.
In a Black Box Attack, the attacker has no knowledge of the model's architecture or parameters, but still manages to manipulate the input to get the desired output. For instance, spammers and hackers often use image-based spam to evade detection by anti-spam filters.
Black Box Attacks can be more difficult to detect than White Box Attacks, as the attacker doesn't leave any digital fingerprints. However, they can still be split into two categories: evasion attacks that exploit the imperfection of a trained model, and those that use influence over the training data.
Here's a breakdown of Black Box Attack types:
- Evasion attacks that exploit the imperfection of a trained model
- Evasion attacks that use influence over the training data (although this is not specific to Black Box Attacks)
These types of attacks are a reminder that even with the most advanced machine learning models, there's always room for improvement in terms of security and robustness.
Compare Perturbation Values
As you compare different attack types and modalities, it's essential to understand how perturbation values affect the robustness of your networks.
Perturbation values can significantly impact the number of verified results. To compare these values, you can specify multiple pairs of input bounds in a single call to the verifyNetworkRobustness function, which can help reduce computation time.
The number of verified results decreases as perturbation values increase for both networks. This means that as the perturbation increases, the number of observations returning verified results decreases.
To visualize this, you can plot the results and see how the number of verified results changes with different perturbation values. This can help you identify the optimal perturbation value for your specific use case.
Deep Reinforcement Learning
Deep reinforcement learning is an active area of research focusing on vulnerabilities of learned policies. This field has shown that reinforcement learning policies are susceptible to imperceptible adversarial manipulations.
Some studies have proposed methods to overcome these susceptibilities, but recent research has revealed that these solutions are far from providing an accurate representation of current vulnerabilities of deep reinforcement learning policies.
Adversarial deep reinforcement learning is a significant concern in this field, and researchers are working to develop more robust policies that can withstand these types of attacks.
Natural Language Processing
Natural Language Processing is a field that's become increasingly vulnerable to attacks. Adversarial natural language processing has been used to compromise speech recognition systems, particularly in speech-to-text applications like Mozilla's DeepSpeech implementation.
These attacks can be particularly sneaky, as they're designed to manipulate language models into producing incorrect results. For example, researchers have shown that small changes to audio inputs can significantly alter speech recognition outputs.
In the case of Mozilla's DeepSpeech, adversarial attacks have been used to compromise its speech-to-text capabilities. This highlights the need for robust security measures in natural language processing systems.
These attacks can have serious consequences, including the spread of misinformation or the compromising of sensitive information. It's essential to stay aware of these risks and take steps to mitigate them.
A unique perspective: Smart Parking Systems Machine Learning
Linear Models
Linear models are a crucial tool in understanding adversarial attacks. They allow for analytical analysis and can reproduce phenomena observed in state-of-the-art models.
The analysis of adversarial attacks in linear models is simplified because the computation of these attacks can be simplified in linear regression and classification problems. This makes them a prime example of how to explain the trade-off between robustness and accuracy.
On a similar theme: Log Linear Models
Linear models are convex in the case of adversarial training, which makes them easier to work with. They can be used to analyze the trade-off between robustness and accuracy in a way that's easy to understand.
The study of adversarial attacks in linear models has been an important tool for understanding how these attacks affect machine learning models.
Sources
- https://towardsdatascience.com/know-your-enemy-7f7c5038bdf3
- https://en.wikipedia.org/wiki/Adversarial_machine_learning
- https://www.mathworks.com/help/deeplearning/ug/verify-robustness-of-deep-learning-network.html
- https://medium.com/@hyponymous/paper-summary-towards-deep-learning-models-resistant-to-adversarial-attacks-ef9d2c195a46
- https://dblp.org/rec/conf/iclr/MadryMSTV18
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