Abstract We continue investigating variants of the splitting and reaping numbers introduced in [4]. In particular, answering a question raised there, we prove the consistency of and of . Moreover, we discuss their natural generalisations $\mathfrak {s}_{\rho }$ and $\mathfrak {r}_{\rho }$ for $\rho \in (0,1)$ , and show that $\mathfrak {r}_{\rho }$ does not depend on $\rho $ .

Parental control applications, software tools designed to manage and monitor children’s online activities, serve as essential safeguards for parents in the digital age. However, their usage has sparked concerns about security and privacy violations inherent in various child monitoring products. Sideloaded software (i.e. apps installed outside official app stores) poses an increased risk, as it is not bound by the regulations of trusted platforms. Despite this, the market of sideloaded parental control software has remained widely unexplored by the research community. This paper examines 20 sideloaded parental control apps and compares them to 20 apps available on the Google Play Store. We base our analysis on privacy policies, Android package kit (APK) files, application behaviour, network traffic and application functionalities. Our findings reveal that sideloaded parental control apps fall short compared to their in-store counterparts, lacking specialised parental control features and safeguards against misuse while concealing themselves on the user's device. Alarmingly, three apps transmitted sensitive data unencrypted, half lacked a privacy policy and 9 out of 20 were flagged for potential stalkerware indicators of compromise (IOC).

Addressing a critical aspect of cybersecurity in online gaming, this paper systematically evaluates the extent to which kernel-level anti-cheat systems mirror the properties of rootkits, highlighting the importance of distinguishing between protective and potentially invasive software. After establishing a definition for rootkits (making distinctions between rootkits and simple kernel-level applications) and defining metrics to evaluate such software, we introduce four widespread kernel-level anti-cheat solutions. We lay out the inner workings of these types of software, assess them according to our previously established definitions, and discuss ethical considerations and the possible privacy infringements introduced by such programs. Our analysis shows two of the four anti-cheat solutions exhibiting rootkit-like behaviour, threatening the privacy and the integrity of the system. This paper thus provides crucial insights for researchers and developers in the field of gaming security and software engineering, highlighting the need for informed development practices that carefully consider the intersection of effective anti-cheat mechanisms and user privacy.

The protection of private information is a crucial issue in data-driven research and business contexts. Typically, techniques like anonymisation or (selective) deletion are introduced in order to allow data sharing, e. g. in the case of collaborative research endeavours. For use with anonymisation techniques, the k-anonymity criterion is one of the most popular, with numerous scientific publications on different algorithms and metrics. Anonymisation techniques often require changing the data and thus necessarily affect the results of machine learning models trained on the underlying data. In this work, we conduct a systematic comparison and detailed investigation into the effects of different k-anonymisation algorithms on the results of machine learning models. We investigate a set of popular k-anonymisation algorithms with different classifiers and evaluate them on different real-world datasets. Our systematic evaluation shows that with an increasingly strong k-anonymity constraint, the classification performance generally degrades, but to varying degrees and strongly depending on the dataset and anonymisation method. Furthermore, Mondrian can be considered as the method with the most appealing properties for subsequent classification.

Today, many different types of scams can be found on the internet. Online criminals are always finding new creative ways to trick internet users, be it in the form of lottery scams, downloading scam apps for smartphones or fake gambling websites. This paper presents a large-scale study on one particular delivery method of online scam: pop-up scam on typosquatting domains. Typosquatting describes the concept of registering domains which are very similar to existing ones while deliberately containing common typing errors; these domains are then used to trick online users while under the belief of browsing the intended website. Pop-up scam uses JavaScript alert boxes to present a message which attracts the user's attention very effectively, as they are a blocking user interface element.