Data brokers collect and sell the personal information of millions of individuals, often without their knowledge or consent. The California Consumer Privacy Act (CCPA) grants consumers the legal right to request access to, or deletion of, their data. To facilitate these requests, California maintains an official registry of data brokers. However, the extent to which these entities comply with the law is unclear. This paper presents the first large-scale, systematic study of CCPA compliance of all 543 officially registered data brokers. Data access requests were manually submitted to each broker, followed by in-depth analyses of their responses (or lack thereof). Above 40% failed to respond at all, in an apparent violation of the CCPA. Data brokers that responded requested personal information as part of their identity verification process, including details they had not previously collected. Paradoxically, this means that exercising one's privacy rights under CCPA introduces new privacy risks. Our findings reveal rampant non-compliance and lack of standardization of the data access request process. These issues highlight an urgent need for stronger enforcement, clearer guidelines, and standardized, periodic compliance checks to enhance consumers' privacy protections and improve data broker accountability.

Internet of Things (IoT) devices are becoming increasingly commonplace in both public and semi-private settings. Currently, most such devices lack mechanisms that allow for their discovery by casual (nearby) users who are not owners or operators. However, these users are potentially being sensed, and/or actuated upon, by these devices, without their knowledge or consent. This triggers privacy, security, and safety issues. To address this problem, some recent work explored device transparency in the IoT ecosystem. The intuitive approach is for each device to periodically and securely broadcast (announce) its presence and capabilities to all nearby users. While effective, when no new users are present, this 𝑃𝑢𝑠ℎ-based approach generates a substantial amount of unnecessary network traffic and needlessly interferes with normal device operation. In this work, we construct DB-PAISA which addresses these issues via a 𝑃𝑢𝑙𝑙-based method, whereby devices reveal their presence and capabilities only upon explicit user request. Each device guarantees a secure timely response (even if fully compromised by malware) based on a small active Root-of-Trust (RoT). DB-PAISA requires no hardware modifications and is suitable for a range of current IoT devices. To demonstrate its feasibility and practicality, we built a fully functional and publicly available prototype. It is implemented atop a commodity MCU (NXP LCP55S69) and operates in tandem with a smartphone-based app. Using this prototype, we evaluate energy consumption and other performance factors.