diff --git "a/INE1T4oBgHgl3EQfFwM8/content/tmp_files/load_file.txt" "b/INE1T4oBgHgl3EQfFwM8/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/INE1T4oBgHgl3EQfFwM8/content/tmp_files/load_file.txt" @@ -0,0 +1,1570 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf,len=1569 +page_content='REaaS: Enabling Adversarially Robust Downstream Classifiers via Robust Encoder as a Service Wenjie Qu1, Jinyuan Jia2, Neil Zhenqiang Gong3 1 Huazhong University of Science and Technology, wen jie qu@outlook.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='com 2 University of Illinois Urbana-Champaign, jinyuan@illinois.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='edu 3 Duke University, neil.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='gong@duke.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='edu Abstract—Encoder as a service is an emerging cloud service.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Specifically, a service provider first pre-trains an encoder (i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', a general-purpose feature extractor) via either supervised learning or self-supervised learning and then deploys it as a cloud service API.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A client queries the cloud service API to obtain feature vectors for its training/testing inputs when training/testing its classifier (called downstream classifier).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A downstream classifier is vulnerable to adversarial examples, which are testing inputs with carefully crafted perturbation that the downstream classifier misclassifies.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, in safety and security critical applications, a client aims to build a robust downstream classifier and certify its robustness guarantees against adversarial examples.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' What APIs should the cloud service provide, such that a client can use any certification method to certify the robustness of its downstream classifier against adversarial examples while minimizing the number of queries to the APIs?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' How can a service provider pre-train an encoder such that clients can build more certifiably robust downstream classifiers?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We aim to answer the two questions in this work.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For the first question, we show that the cloud service only needs to provide two APIs, which we carefully design, to enable a client to certify the robustness of its downstream classifier with a minimal number of queries to the APIs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For the second question, we show that an encoder pre- trained using a spectral-norm regularization term enables clients to build more robust downstream classifiers.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' I.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' INTRODUCTION In an encoder as a service, a service provider (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', OpenAI, Google, and Amazon) pre-trains a general-purpose feature extractor (called encoder) and deploys it as a cloud service;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' and a client queries the cloud service APIs for the feature vectors of its training/testing inputs when training/testing a downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For instance, the encoder could be pre- trained using supervised learning on a large amount of labeled data or self-supervised learning [1], [2] on a large amount of unlabeled data.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A client could be a smartphone, IoT device, self-driving car, or edge device in the era of edge computing.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Encoder as a service has been widely deployed by industry, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', OpenAI’s GPT-3 API [3] and Clarifai’s General Embedding API [4].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In the Standard Encoder as a Service (SEaaS), the service provides a single API (called Feature-API) for clients Wenjie Qu performed this research when he was an intern in Gong’s group.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' and the encoder is pre-trained without taking the robustness of downstream classifiers into consideration.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A client sends its training/testing inputs to the Feature-API, which returns their feature vectors to the client.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A downstream classifier is vulnerable to adversarial exam- ples [5], [6].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Suppose a testing input is correctly classified by the downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' An attacker adds a small carefully crafted perturbation to the testing input to induce misclassification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Such testing input with carefully crafted perturbation is called an adversarial example.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, in security and safety critical applications such as user authentication and traffic sign recognition, a client desires to build a downstream classifier robust against adversarial examples.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Many methods have been developed for an attacker to craft adversarial examples and the community keeps developing new, stronger ones.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, instead of defending against a specific class of adversarial examples, a client aims to defend against all bounded adversarial perturbations via building a certifiably robust downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A classifier is certifiably robust if its predicted label for a testing input is unaffected by arbitrary perturbation added to the testing input once its size (measured by ℓ2-norm in this work) is less than a threshold, which is known as certified radius.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A larger certified radius indicates better certified robustness against adversarial examples.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In general, there are two categories of complementary methods to build a certifiably robust classifier and derive its certified radius for a testing input, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', base classifier (BC) based certification [7], [8], [9], [10] and smoothed classifier (SC) based certification (also known as randomized smoothing) [11], [12], [13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' BC based certification aims to directly derive the certified radius of a given classifier (called base classifier) for a testing input.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' BC based certification requires white-box access to the base classifier as it often requires propagating the perturbation from the input layer to the output layer of the base classifier layer by layer.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' SC based certification first builds a smoothed classifier based on the base classifier via adding random noise (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', Gaussian noise) to a testing input and then derives the certified radius of the smoothed classifier for the testing input.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' To increase the testing inputs’ certified radii, SC based certification often requires training the base classifier using training inputs with random noise.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Moreover, to derive the predicted label and certified radius for a testing input, SC based certification requires the base classifier to predict the labels of multiple noisy versions of the testing input.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' SEaaS faces three challenges when a client aims to build a certifiably robust downstream classifier and derive its certified Network and Distributed System Security (NDSS) Symposium 2023 28 February - 4 March 2023, San Diego, CA, USA ISBN 1-891562-83-5 https://dx.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='doi.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='org/10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='14722/ndss.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='2023.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='24444 www.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='ndss-symposium.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='org arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='02905v1 [cs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='CR] 7 Jan 2023 SEaaS REaaS Feature-API Feature-API F2IPerturb-API [0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='1, ⋯, 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='2] Cloud Server Client Client Cloud Server Encoder Encoder � [0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='1, ⋯, 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='2] Downstream Classifier Step 1 Step 2 Step 3 BC/SC Fig.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' 1: SEaaS vs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' radii for testing inputs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The first challenge is that a client cannot use BC based certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In particular, the composition of the encoder and the client’s downstream classifier is the base classifier that the client needs to certify in BC based certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' However, the client does not have white-box access to the encoder deployed on the cloud server, making BC based certification not applicable.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The second challenge is that, although a client can use SC based certification by treating the composition of the encoder and its downstream classifier as a base classifier, it incurs a large communication cost for the client and a large computation cost for the cloud server.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Specifically, the client needs to query the Feature-API once for each noisy training input in each training epoch of the downstream classifier because SC based certification trains the base classifier using noisy training inputs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, the client requires e queries to the Feature-API per training input, where e is the number of epochs used to train the downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Moreover, to derive the predicted label and certified radius for a testing input, SC based certification requires the base classifier to predict the labels of N noisy testing inputs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, the client requires N queries to the Feature-API per testing input.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Note that N is often a large number (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', 10,000) [13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The large number of queries to the Feature- API imply 1) large communication cost, which is intolerable for resource-constrained clients such as smartphone and IoT devices, and 2) large computation cost for the cloud server.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The third challenge is that SC based certification achieves suboptimal certified radii.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' This is because the base classifier is the composition of the encoder and a client’s downstream classifier, but a client cannot train/fine-tune the encoder as it is deployed on the cloud server.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our work: We propose Robust Encoder as a Service (REaaS) to address the three challenges of SEaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Figure 1 compares SEaaS with REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our key idea is to provide another API called F2IPerturb-API.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='1 A downstream classifier essentially takes a feature vector as input and outputs a label.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our F2IPerturb-API enables a client to treat its downstream classifier alone as a base classifier and certify the robustness of its base or smoothed downstream classifier in the feature space.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Specifically, a client performs three steps to derive the certified radius of a testing input in REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' First, the client obtains the feature vector of the testing input via querying the Feature-API.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Second, the client views its downstream classifier alone as a base classifier and derives a feature-space certified radius RF for the testing input using any BC/SC certification method.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The client’s base or smoothed downstream classifier predicts the same label for the testing input if the ℓ2-norm of the adversarial perturbation added to the testing input’s feature vector is less 1‘F’ stands for Feature and ‘I’ stands for Input.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' than RF .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Third, the client sends the testing input and its feature- space certified radius RF to query the F2IPerturb-API, which returns the corresponding input-space certified radius R to the client.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our input-space certified radius R guarantees the client’s base or smoothed downstream classifier predicts the same label for the testing input if the ℓ2-norm of the adversarial perturbation added to the testing input is less than R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The key challenge of implementing our F2IPerturb-API is how to find the largest input-space certified radius R for a given testing input and its feature-space certified radius RF .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' To address the challenge, we formulate finding the largest R as an optimization problem, where the objective function is to find the maximum R and the constraint is that the feature- space perturbation is less than RF .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' However, the optimization problem is challenging to solve due to the highly non-linear constraint.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' To address the challenge, we propose a binary search based solution.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The key component of our solution is to check whether the constraint is satisfied for a specific R in each iteration of binary search.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Towards this goal, we derive an upper bound of the feature-space perturbation for a given R and we treat the constraint satisfied if the upper bound is less than RF .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our upper bound can be computed efficiently.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' F2IPerturb-API addresses the first two challenges of SEaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Specifically, BC based certification is applicable in REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Moreover, SC based certification requires much less queries to the APIs in REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Specifically, for any certification method, a client only requires one query to Feature-API per training input and two queries (one to Feature-API and one to F2IPerturb-API) per testing input in our REaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' To address the third challenge of SEaaS, we propose a new method to pre-train a robust encoder, so a client can derive larger certified radii even though it cannot train/fine-tune the encoder.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our method can be combined with standard supervised learning or self-supervised learning to enhance the robustness of a pre-trained encoder.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' An encoder is more robust if it produces more similar feature vectors for an input and its adversarially perturbed version.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our key idea is to derive an upper bound for the Euclidean distance between the feature vectors of an input and its adversarial version, where our upper bound is a product of a spectral-norm term and the perturbation size.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The spectral- norm term depends on the parameters of the encoder, but it does not depend on the input nor the adversarial perturbation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' An encoder with a smaller spectral-norm term may produce more similar feature vectors for an input and its adversarial version.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Thus, we use the spectral-norm term as a regularization term to regularize the pre-training of an encoder.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We perform a systematic evaluation on multiple datasets including CIFAR10, SVHN, STL10, and Tiny-ImageNet.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Our 2 evaluation results show that REaaS addresses the three chal- lenges of SEaaS.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' First, REaaS makes BC based certification ap- plicable.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Second, REaaS incurs orders of magnitude less queries to the cloud service than SEaaS for SC based certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For instance, REaaS reduces the number of queries to the cloud service APIs respectively by 25× and 5, 000× per training and testing input when a client trains its downstream classifier for e = 25 epochs and uses N = 10, 000 for certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Third, in the framework of REaaS, our robust pre-training method achieves larger average certified radius (ACR) for the testing inputs than existing methods to pre-train encoders for both BC and SC based certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For instance, when the encoder is pre-trained on Tiny-ImageNet and the downstream classifier is trained on SVHN, the ACRs for MoCo (a standard non-robust self-supervised learning method) [1], RoCL (an adversarial training based state-of-the-art robust self-supervised learning method) [14], and our method are respectively 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='011, 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='014, and 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='275 when a client uses SC based certification.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In summary, we make the following contributions: We propose REaaS, which enables a client to build a certifiably robust downstream classifier and derive its certified radii using any certification method with a minimal number of queries to the cloud service.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We propose a method to implement F2IPerturb-API.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We propose a spectral-norm term to regularize the pre-training of a robust encoder.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We extensively evaluate REaaS and compare it with SEaaS on multiple datasets.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' II.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' RELATED WORK A.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Adversarial Examples We discuss adversarial examples [5], [15] in the context of encoder as a service.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We denote by f a pre-trained encoder and g a downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Given a testing input x, the encoder outputs a feature vector for it, while the downstream classifier takes the feature vector as input and outputs a label.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' For simplicity, we denote by f(x) the feature vector and g◦f(x) the predicted label for x, where ◦ represents the composition of the encoder and downstream classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In an adversarial example, an attacker adds a carefully crafted small perturbation δ to x such that its predicted label changes, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', g ◦f(x+δ) ̸= g ◦ f(x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' The carefully perturbed input x + δ is called an adversarial example.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Many methods (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', [5], [6], [16]) have been proposed to find an adversarial perturbation δ for a given input x.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' In our work, we focus on certified defenses, which aim to defend against any bounded adversarial perturbations no matter how they are found.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, we omit the details on how an attacker can find an adversarial perturbation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' B.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Certifying Robustness of a Classifier Definition of certified radius: A classifier is certifiably robust against adversarial examples if its predicted label for an input is unaffected by any perturbation once its size is bounded [7], [12], [13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Formally, a classifier h is certifiably robust if we have the following guarantee for an input x: h(x + δ) = h(x), ∀ ∥δ∥2 < R, (1) where R is known as certified radius.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Note that certified radius R may be different for different inputs x, but we omit the explicit dependency on x in the notation for simplicity.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' A certification method against adversarial examples aims to build a certifiably robust classifier and derive its certified radius R for any input x.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' There are two general categories of certification methods, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', base classifier (BC) based certification [7], [8], [9], [10] and smoothed classifier (SC) based certification [11], [12], [13].' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Both categories of methods may be adopted in different scenarios depending on certification needs.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' On one hand, BC based certification often produces deterministic guarantees (i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', the derived certified radius is absolutely correct), while SC based certification often provides probabilistic guarantees (i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', the derived certified radius may be incorrect with a small error probability).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' On the other hand, SC based certification often derives a larger certified radius than BC based certification due to its probabilistic guarantees.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Base classifier (BC) based certification: BC based certi- fication aims to directly derive the certified radius R of a given classifier (called base classifier) for an input x.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' These methods often propagate perturbation from the input x to the output of the base classifier layer by layer in order to derive the certified radius.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Therefore, they require white-box access to the base classifier.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Suppose F is a base classifier that maps an input x to one of c classes {1, 2, · · · , c}.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' We use H(x) to denote the base classifier’s last-layer output vector for x, where Hl(x) represents the lth entry of H(x) and l = 1, 2, · · · , c.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' F(x) denotes the predicted label for x, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', F(x) = argmaxl=1,2,··· ,c Hl(x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Next, we overview how to derive the certified radius R using CROWN [9], a state-of-the- art BC based certification method.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' CROWN shows that each entry Hl(x) can be bounded by two linear functions HL l (x) and HU l (x).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' Suppose the base classifier predicts label y for x when there is no adversarial perturbation, i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', F(x) = y.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=' CROWN finds the largest r such that the lower bound of the yth entry (i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/INE1T4oBgHgl3EQfFwM8/content/2301.02905v1.pdf'} +page_content=', min∥δ∥2