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  1. Generative models are now capable of synthesizing images, speeches, and videos that are hardly distinguishable from authentic contents. Such capabilities cause concerns such as malicious impersonation and IP theft. This paper investigates a solution for model attribution, i.e., the classification of synthetic contents by their source models via watermarks embedded in the contents. Building on past success of model attribution in the image domain, we discuss algorithmic improvements for generating user-end speech models that empirically achieve high attribution accuracy, while maintaining high generation quality. We show the tradeoff between attributability and generation quality under a variety of attacks on generated speech signals attempting to remove the watermarks, and the feasibility of learning robust watermarks against these attacks. 
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  2. null (Ed.)
    The emergence of programmable switches offers a new opportunity to revisit ISP-scale defenses for volumetric DDoS attacks. In theory, these can offer better cost vs. performance vs. flexibility trade-offs relative to proprietary hardware and virtual appliances. However, the ISP setting creates unique challenges in this regard---we need to run a broad spectrum of detection and mitigation functions natively on the programmable switch hardware and respond to dynamic adaptive attacks at scale. Thus, prior efforts in using programmable switches that assume out-of-band detection and/or use switches merely as accelerators for specific tasks are no longer sufficient, and as such, this potential remains unrealized. To tackle these challenges, we design and implement Jaqen, a switch-native approach for volumetric DDoS defense that can run detection and mitigation functions entirely inline on switches, without relying on additional data plane hardware. We design switch-optimized, resource-efficient detection and mitigation building blocks. We design a flexible API to construct a wide spectrum of best-practice (and future) defense strategies that efficiently use switch capabilities. We build a network-wide resource manager that quickly adapts to the attack posture changes. Our experiments show that Jaqen is orders of magnitude more performant than existing systems: Jaqen can handle large-scale hybrid and dynamic attacks within seconds, and mitigate them effectively at high line-rates (380 Gbps). 
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  3. The emergence of programmable switches offers a new opportunity to revisit ISP-scale defenses for volumetric DDoS attacks. In theory, these can offer better cost vs. performance vs. flexibility trade-offs relative to proprietary hardware and virtual appliances. However, the ISP setting creates unique challenges in this regard---we need to run a broad spectrum of detection and mitigation functions natively on the programmable switch hardware and respond to dynamic adaptive attacks at scale. Thus, prior efforts in using programmable switches that assume out-of-band detection and/or use switches merely as accelerators for specific tasks are no longer sufficient, and as such, this potential remains unrealized. To tackle these challenges, we design and implement Jaqen, a switch-native approach for volumetric DDoS defense that can run detection and mitigation functions entirely inline on switches, without relying on additional data plane hardware. We design switch-optimized, resource-efficient detection and mitigation building blocks. We design a flexible API to construct a wide spectrum of best-practice (and future) defense strategies that efficiently use switch capabilities. We build a network-wide resource manager that quickly adapts to the attack posture changes. Our experiments show that Jaqen is orders of magnitude more performant than existing systems: Jaqen can handle large-scale hybrid and dynamic attacks within seconds, and mitigate them effectively at high line-rates (380 Gbps). 
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  4. Growing applications of generative models have led to new threats such as malicious personation and digital copyright infringement. One solution to these threats is model attribution, i.e., the identification of user-end models where the contents under question are generated from. Existing studies showed empirical feasibility of attribution through a centralized classifier trained on all user-end models. However, this approach is not scalable in reality as the number of models ever grows. Neither does it provide an attributability guarantee. To this end, this paper studies decentralized attribution, which relies on binary classifiers associated with each user-end model. Each binary classifier is parameterized by a user-specific key and distinguishes its associated model distribution from the authentic data distribution. We develop sufficient conditions of the keys that guarantee an attributability lower bound. Our method is validated on MNIST, CelebA, and FFHQ datasets. We also examine the trade-off between generation quality and robustness of attribution against adversarial post-processes. 
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  5. Programmable switches have been touted as an attractive alternative for deploying network functions (NFs) such as network address translators (NATs), load balancers, and firewalls. However, their limited memory capacity has been a major stumbling block that has stymied their adoption for supporting state-intensive NFs such as cloud-scale NATs and load balancers that maintain millions of flow-table entries. In this paper, we explore a new approach that leverages DRAM on servers available in typical NFV clusters. Our new system architecture, called TEA (Table Extension Architecture), provides a virtual table abstraction that allows NFs on programmable switches to look up large virtual tables built on external DRAM. Our approach enables switch ASICs to access external DRAM purely in the data plane without involving CPUs on servers. We address key design and implementation challenges in realizing this idea. We demonstrate its feasibility and practicality with our implementation on a Tofino-based programmable switch. Our evaluation shows that NFs built with TEA can look up table entries on external DRAM with low and predictable latency (1.8-2.2 μs) and the lookup throughput can be linearly scaled with additional servers (138 million lookups per seconds with 8 servers). 
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