User tracking and profiling is a growing threat to online privacy. Whilst Internet users can choose to withhold their personal information, their Internet usage can still be traced back to a unique IP address. This study considers anonymity as a strong and useful form of privacy protection. More specifically, we examine how current anonymity solutions suffer from a number of deficiencies: they are not commonly used, are vulnerable to a host of attacks or are impractical or too cumbersome for daily use. Most anonymity solutions are centralised or partially centralised and require trust in the operators. It is additionally noted how current solutions fail to promote anonymity for common Web activities such as performing online search queries and general day-to-day Web browsing. A primary objective of this research is to develop an anonymising Web browsing protocol which aims to be (1) fully distributed, (2) offer adequate levels of anonymity and (3) enable users to browse the Internet anonymously without overly complex mixing techniques. Our research has led to an anonymising protocol called Polar. Polar is a peer-to-peer network which relays Web requests amongst peers before forwarding it to a Web server, thus protecting the requester's identity. This dissertation presents the Polar model. Design choices and enhancements to the model are discussed. The author's implementation of Polar is also presented demonstrating that an implementation of Polar is feasible. / Dissertation (MSc (Computer Science))--University of Pretoria, 2007. / Computer Science / unrestricted

Proving and verifying remotely a user's identity information have become a critical and challenging problem in the online world, with the increased number of sensitive services offered online. The digital identity management ecosystem has been evolving over the years to address this problem. However, the limitations in existing identity management approaches in handling this problem in a privacy preserving and secure manner have caused disruptions to users' digital lives and damages to revenue and reputation of service providers.<br><br>In this dissertation, we analyze different areas of the identity management ecosystem in terms of privacy and security. In our analysis, we observe three critical aspects to take into account when identifying the privacy and security requirements to address in identity management scenarios, namely: i) protecting privacy and security of digital identity and online transactions of users; ii) providing other stakeholders with assurance about user identity information and accountability of transactions; iii) preserving utility (e.g. accuracy, efficiency and deployability).<br>We show that existing authentication models and identity management protocols fail to address critical privacy and security requirements related to all these three aspects, mainly because of inherent conflicts among these requirements. <br>For example, existing authentication protocols, which aim to protect service providers from imposters by involving strong authentication factors, such as biometrics, fail to protect privacy and security of users' biometrics. Protecting an identity management system against counterfeits of identity assets, while preserving unlinkability of the transactions carried out using the identity assets, is another example of conflicting yet critical privacy and security requirements.<br>We demonstrate that careful combinations of cryptographic techniques and other technologies make it feasible to design privacy preserving identity management protocols which address critical and conflicting requirements related to the aforementioned three aspects. Certain techniques, that we have developed for these protocols, are independent contributions with applications beyond the domain of digital identity management. We validate our contributions by providing prototype implementations, experimental evaluations and security proofs.

The popularity of cannabis and reduction of cannabis prohibition in the United States has led to increased consumption in human users. However, relatively little is understood about the abuse potential of cannabis and its main psychoactive ingredient, THC. One reason for the lack of insight into the addictive effects of THC is that the animal models investigating voluntary intake of THC have been hampered by low rates of behavior and THC intake often does not surpass intake of vehicle. We hypothesized that, in addition to supporting operant behavior (smoking, vaping, or consuming edibles) THC might increase the reinforcing effects of non-drug rewards (e.g., playing video games, listening to music, eating snacks). To investigate this hypothesis, we evaluated whether THC injections could increase responding for saccharin (0.2% w/v, SACC) in male and female rats. During our investigation we noted that the pharmacology of THC was complex, with potent motor suppressant effects, and that changes in behavior depended on the pharmacokinetics of THC administration. To further explore the pharmacokinetics, we conducted 3 experiments that manipulated THC dose (Experiment 1), Injection-Test interval (Experiment 2) and Injection-Injection interval (washout duration, Experiment 3). We hypothesized that THC would increase responding for SACC, but that this effect would depend on having a longer time between sessions to reduce motor-suppressing effects of THC accumulation. Male and female rats were shaped to respond for SACC under a progressive ratio (PR) schedule of reinforcement. The PR schedule measures motivation by increasing the response requirement after each reinforcer is earned. In Experiment 1 there was a significant effect of THC dose, with moderate doses (0.3-0.75 mg/kg) increasing motivation for SACC and high doses (3 mg/kg) causing significant motor suppression. In Experiment 2 (Injection-Test interval) we found that the timing of THC injections was critical – enhancing effects were observed soon after THC injections were administered (30-60 min) but after 120 min THC no longer increased motivation for SACC. Finally, in Experiment 3 (Injection-Injection interval) we found that daily injections of THC (24 h washout) resulted in significant decreases in motivation from Session 1 to session 8. In contrast, 72 h washout intervals resulted in stable enhancement of motivation for SACC by THC. These studies indicate that the reinforcement enhancing effects of THC are robust but depend critically on the pharmacokinetics and bioavailability of THC.

Patients with a tuberculoma typically present with pulmonary involvement of tuberculosis and have risk factors for tuberculosis (TB). The risk factors for tuberculosis include bacillary load, proximity to infectious case, immunosuppressive conditions, malnutrition, young age, diabetes mellitus, working in healthcare, recent incarceration, alcohol use, and tobacco use. Although rare, it is possible for a patient to present with a tuberculoma despite the absence of risk factors for tuberculosis other than diabetes and without pulmonary involvement.

This study investigates the connection between one's adult attachment style and one's evaluation of verifying or enhancing comforting messages. Drawing from research by Swann (2005) and Katz and Joiner (2002), the hypothesis predicted that an individual would prefer verifying messages over enhancing messages regardless of attachment style. A research question was also posed: Will an individual's adult attachment style moderate the degree to which a person perceives the communication of verifying or enhancing messages as helpful or effective? In an effort to find these answers, a questionnaire was completed by 251 individuals. Results indicate a preference for verifying messages among participants regardless of attachment style. This is consistent with the findings of Katz and Joiner (2002) and Swann (2005). However, results did not indicate a significant difference between attachment style and a preference of enhancing or verifying messages.

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<p dir="ltr">In this era of digital surveillance and data breaches, it is important to understand how users protect their smartphone privacy. There needs to be more detailed information regarding the prevalence, factors, and motivations influencing the adoption of privacy-enhancing tools and settings on mobile devices. This study aimed to address this knowledge gap by investigating the use of privacy tools among smartphone users and examining the impact of factors like demographics, awareness levels, and device platforms.</p><p dir="ltr">The study surveyed 342 participants recruited through Amazon Mechanical Turk (MTurk), and the data were analyzed. The survey gathered data on user characteristics, privacy concerns, experiences with breaches, and use of various privacy tools. Statistical analysis showed that demographic factors, particularly age, significantly influenced the use of privacy tools, aligning with previous research. Users with a higher awareness of digital privacy risks were likelier to adopt privacy-enhancing tools. The study found no significant difference in the prevalence and type of privacy tools used between iOS and Android users.</p><p dir="ltr">The study's focus on privacy-enhancing tools among smartphone users and the proposed hypotheses provide valuable insights for law enforcement and forensic practitioners, aiding in digital investigations, evidence collection, and understanding user behavior related to smartphone privacy measures. The study's outcomes contribute to digital forensics, cybersecurity, and privacy domains by providing insights into user behaviors, motivations, and the factors shaping privacy tool adoption on smartphones. These findings can inform the development of more user-centric privacy tools, policies, and educational campaigns, ultimately enhancing digital privacy protection and supporting law enforcement investigations in the digital age.</p>

PET-CON, the Privacy Enhancing Technologies Convention, is a forum for researchers, students, developers, and other interested people to discuss novel research, current development and techniques in the area of Privacy Enhancing Technologies. PET-CON was first conceived in June 2007 at the 7th International PET Symposium in Ottawa, Canada. The idea was to set up a bi-annual convention in or nearby Germany to be able to meet more often than only once a year at some major conference.

PET-CON, the Privacy Enhancing Technologies Convention, is a forum for researchers, students, developers, and other interested people to discuss novel research, current development and techniques in the area of Privacy Enhancing Technologies. PET-CON was first conceived in June 2007 at the 7th International PET Symposium in Ottawa, Canada. The idea was to set up a bi-annual convention in or nearby Germany to be able to meet more often than only once a year at some major conference.