Secure authentication on situated displays (e.g., to access sensitive information or to make purchases) is becoming increasingly important. A promising approach to resist shoulder surfing attacks is to employ cues that users respond to while authenticating; this overwhelms observers by requiring them to observe both the cue itself as well as users' response to the cue. Although previous work proposed a variety of modalities, such as gaze and mid-air gestures, to further improve security, an understanding of how they compare with regard to usability and security is still missing as of today. In this paper, we rigorously compare modalities for cue-based authentication on situated displays. In particular, we provide the first comparison between touch, mid-air gestures, and calibration-free gaze using a state-of-the-art authentication concept. In two in-depth user studies (N=37) we found that the choice of touch or gaze presents a clear trade-off between usability and security. For example, while gaze input is more secure, it is also more demanding and requires longer authentication times. Mid-air gestures are slightly slower and more secure than touch but users hesitate to use them in public. We conclude with three significant design implications for authentication using touch, mid-air gestures, and gaze and discuss how the choice of modality creates opportunities and challenges for improved authentication in public. CCS Concepts: • Security and privacy → Authentication; • Human-centered computing → Human computer interaction (HCI); Interaction techniques; Interaction design;

Recent work has questioned the largely unconditional nature of charitable donations and explored the value of conditional giving with contemporary donors. In this paper, we extend this work by exploring how to operationalise features of conditionality in charitable giving, situated in the context of large international non-governmental organisations (NGOs). Building on prior engagements with international aid organisations, we present design considerations and a conceptual architecture supporting real-time, conditional giving for individual and institutional donations. Our architecture leverages properties of distributed-ledger technologies (DLT) to empower donors to (i) attach conditions to their donation, (ii) store funds in a secure, decentralised escrow and (iii) automatically release funds once conditions are met. Unlike prior work that envisions radical disintermediation and the removal of intermediate NGOs using DLT, our work recognises the expertise of NGOs in tackling complex global problems and instead investigates compelling new way for charities to increase transparency and accountability by introducing dynamic pledge controls. CCS Concepts: • Social and professional topics → Socio-technical systems; • Human-centered computing → Mobile computing; • Information systems → Collaborative and social computing systems and tools.

This paper reports on a co-speculative interview study with charitable donors to explore the future of programmable, conditional and data-driven donations. Responding to the rapid emergence of blockchain-based and AI-supported financial technologies, we specifically examine the potential of automated, third-party 'escrows', where donations are held before they are released or returned based on specified rules and conditions. To explore this we conducted pilot workshops with 9 participants and an interview study in which 14 further participants were asked about their experiences of donating money, and invited to co-speculate on a service for programmable giving. The study elicited how data-driven conditionality and automation could be leveraged to create novel donor experiences, however also illustrated the inherent tensions and challenges involved in giving programmatically. Reflecting on these findings, our paper contributes implications both for the design of programmable aid platforms, and the design of escrow-based financial services in general. CCS CONCEPTS • Human-centered computing → User studies.

IoT technologies are increasingly being deployed to support the operation and maintenance of complex highways infrastructure assets. However, the use of interconnected cyber-physical systems in such critical infrastructure raises important privacy, safety and security issues. While security issues in IoT transport systems and autonomous vehicles are well studied, there is minimal research relating to cyber security in the field of highways maintenance. In this paper, we introduce the problem domain, evidence the lack of existing research and provide example threats to IoT highways maintenance systems based on a realworld case study.

Although recovering from errors is straightforward on most interfaces, public display systems pose very unique design challenges. Namely, public display users interact for very short amounts of times and are believed to abandon the display when interrupted or forced to deviate from the main task. To date, it is not well understood whether public display designers should enable users to correct errors (e.g. by asking users to confirm or giving them a chance correct their input), or aim for faster interaction and rely on other types of feedback to estimate errors. To close this gap, we conducted a field study where we investigated the users willingness to correct their input on public displays. We report on our findings from an in-the-wild deployment of a public gaze-based voting system where we intentionally evoked system errors to see if users correct them. We found that public display users are willing to correct system errors provided that the correction is fast and straightforward. We discuss how our findings influence the choice of interaction methods for public displays; interaction methods that are highly usable but suffer from low accuracy can still be effective if users can "undo" their interactions.

Smart Donations is a blockchain-based platform that enables users to program and set conditions on charitable donations. Users set up contracts to donate in response to real-world events, e.g., whenever an earthquake is detected or an activist tweets about refugees. We designed Smart donations with Oxfam Australia, trialled it over 8-weeks with 86 people and qualitatively analysed questionnaires and interviews about their experiences. Temporal qualities emerge when automation enforces conditions that determine when donations are made. These contributed to participants' sense of immediacy in donating to humanitarian crises, ongoing involvement while awaiting conditions to be met, and awareness of events that are usually unconscious. We suggest that automation can reveal diverse temporal registers, in real-world phenomena, sociality, morality and everyday life, which contribute to experiencing a 'right time' to donate. Thus, we recommend adopting a sensitivity to right time in designing for multiple temporalities in FinTech more generally.

Social and professional topics → Socio-technical systems; • Human-centered computing → Mobile computing; • Information systems → Collaborative and social computing systems and tools;

The increase in IoT sensing and actuating devices that are seamlessly integrated into the environment is often leading to a mistrust of users as it becomes impossible to spot deployed IoT devices and understand their purposes and capabilities. One approach is to provide an appropriate mechanism of mapping the IoT and address stakeholder requirements. However, providing comprehensive maps of the IoT may expose a number of vulnerabilities that need to be addressed. We conducted a comprehensive literature survey outlining the limitations of the existing body of work regarding the mapping of the IoT and conducting an appropriate threat analysis. We subsequently applied the STRIDE model to two case studies (smart campus and urban environment) to identify a set of potential vulnerabilities and approaches at addressing these issues in the context of IoT maps.