This paper analyzes Google Home, Apple HomeKit, Samsung SmartThings, and Amazon Alexa platforms, focusing on their integration with the Matter protocol. Matter is a connectivity standard developed by the Connectivity Standards Alliance (CSA) for the smart-home industry. By examining key features and qualitative metrics, this study aims to provide valuable insights for consumers and industry professionals in making informed decisions about smart-home devices. We conducted (from May to August 2024) a comparative analysis to explore how Google Home Nest, Apple HomePod Mini, Samsung SmartThings station, and Amazon Echo Dot platforms leverage the power of Matter to provide seamless and integrated smart-home experiences.

With 'smart' technology becoming more prevalent in homes, computing is increasingly embedded into everyday life. The benefits are well-advertised, but the risks associated with these technologies are not as clearly articulated. We aim to address this gap by educating community members on some of these risks, and providing actionable advice to mitigate risks. To this end, we describe our efforts to design and implement a hands-on workshop for the public on smart-home security and privacy.

Harmonic radar systems have been shown to be an effective method for detecting the presence of electronic devices, even if the devices are powered off. Prior work has focused on detecting specific non-linear electrical components (such as transistors and diodes) that are present in any electronic device. In this paper we show that harmonic radar is also capable of detecting the presence of batteries. We tested a proof-of-concept system on Alkaline, NiMH, Li-ion, and Li-metal batteries. With the exception of Li-metal coin cells, the prototype harmonic radar detected the presence of batteries in our experiments with 100% accuracy.

A key feature of smart home devices is monitoring the environment and recording data. These devices provide security via motion-detection video alerts, cost-savings via thermostat usage history, and peace of mind via functions like auto-locking doors or water leak detectors. At the same time, the sharing of this information in interpersonal relationships---though necessary---is currently accomplished on an all-or-nothing basis. This can easily lead to oversharing in a multi-user environment. Although prior work has studied people's perceptions of information sharing with vendors or ISPs, the sharing of household data among users who interact personally is less well understood. Interpersonal situations make data sharing much more context-based and, thus, more complicated. In this paper, we use themes from the theory of contextual integrity in an online survey (n=1,992) to study how people perceive data sharing with others in smart homes and inform future designs and research. Our results show that data recipients in a smart home can be reduced to three major groups, and data types matter more than device types. We also found that the types of access control desired by users can vary from scenario to scenario. Depending on whom they are sharing data with and about what data, participants expressed varying levels of comfort when presented with different types of access control (e.g., explicit approval versus time-limited access). Taken together, this provides strong evidence that a more dynamic access control system is needed, and we can design it in a more usable way.

Although user authentication has been well explored, device-to-device authentication - specifically in Bluetooth networks - has not seen the same attention. We propose Verification of Interaction Authenticity (VIA) - a recurring authentication scheme based on evaluating characteristics of the communications (interactions) between devices. We adapt techniques from wireless traffic analysis and intrusion-detection systems to develop behavioral models that capture typical, authentic device interactions (behavior); these models enable recurring verification of device behavior. To evaluate our approach we produced a new dataset consisting of more than 300 Bluetooth network traces collected from 20 Bluetooth-enabled smart-health and smart-home devices. In our evaluation, we found that devices can be correctly verified at a variety of granularities, achieving an F1-score of 0.86 or better in most cases.

Providing secure communications between wireless devices that encounter each other on an ad-hoc basis is a challenge that has not yet been fully addressed. In these cases, close physical proximity among devices that have never shared a secret key is sometimes used as a basis of trust; devices in close proximity are deemed trustworthy while more distant devices are viewed as potential adversaries. Because radio waves are invisible, however, a user may believe a wireless device is communicating with a nearby device when in fact the user's device is communicating with a distant adversary. Researchers have previously proposed methods for multi-antenna devices to ascertain physical proximity with other devices, but devices with a single antenna, such as those commonly used in the Internet of Things, cannot take advantage of these techniques.

Secure communication is difficult to arrange between devices that have not previously shared a secret. Previous solutions to the problem are susceptible to man-in-the-middle attacks, require additional hardware for out-of-band communication, or require an extensive public-key infrastructure. Furthermore, as the number of wireless devices explodes with the advent of the Internet of Things, it will be impractical to manually configure each device to communicate with its neighbors. Our system, CloseTalker, allows simple, secure, ad hoc communication between devices in close physical proximity, while jamming the signal so it is unintelligible to any receivers more than a few centimeters away. CloseTalker does not require any specialized hardware or sensors in the devices, does not require complex algorithms or cryptography libraries, occurs only when intended by the user, and can transmit a short burst of data or an address and key that can be used to establish long-term or long-range communications at full bandwidth. In this paper we present a theoretical and practical evaluation of CloseTalker, which exploits Wi-Fi MIMO antennas and the fundamental physics of radio to establish secure communication between devices that have never previously met. We demonstrate that CloseTalker is able to facilitate secure in-band communication between devices in close physical proximity (about 5~cm), even though they have never met nor shared a key.

Close physical proximity among wireless devices that have never shared a secret key is sometimes used as a basis of trust. In these cases, devices in close proximity are deemed trustworthy while more distant devices are viewed as potential adversaries. Because radio waves are invisible, however, a user may believe a wireless device is communicating with a nearby device when in fact the user's device is communicating with a distant adversary. Researchers have previously proposed methods for multi-antenna devices to ascertain physical proximity with other devices, but devices with a single antenna, such as those commonly used in the Internet of Things, cannot take advantage of these techniques. We investigate a method for a single-antenna Wi-Fi device to quickly determine proximity with another Wi-Fi device. Our approach leverages the repeating nature Wi-Fi's preamble and the characteristics of a transmitting antenna's near field to detect proximity with high probability. Our method never falsely declares proximity at ranges longer than 14 cm.

Nearly every setting is increasingly populated with wireless and mobile devices - whether appliances in a home, medical devices in a health clinic, sensors in an industrial setting, or devices in an office or school. There are three fundamental operations when bringing a new device into any of these settings: to configure the device to join the wireless local-area network, to partner the device with other nearby devices so they can work together, and (3) to configure the device so it connects to the relevant individual or organizational account in the cloud. The challenge is to accomplish all three goals simply, securely, and consistent with user intent. We present a novel approach we call Wanda - a `magic wand' that accomplishes all three of the above goals - and evaluate a prototype implementation.