Tools for Achieving Usable Ex Post Transparency: A Survey <s> III. RELATED WORK <s> This paper provides a short survey on transparency tools for privacy purposes. It defines the term transparency tools, argues why they are important and gives examples for transparency tools. A classification of transparency tools is suggested and some example tools are analyzed with the help of the classification. <s> BIB001 </s> Tools for Achieving Usable Ex Post Transparency: A Survey <s> III. RELATED WORK <s> As the amount of users' information collected and exchanged on the Internet is growing, so are, consequently, the users' concerns that their privacy might be violated. Some studies have shown that a large number of users avoid engaging in online services due to privacy concerns. It has been suggested that increased transparency of privacy related mechanisms may promote users' trust. This paper reviews the relationship between users' privacy concerns, transparency enhancing and privacy enhancing mechanisms on the one hand, and users' trust on the other, based on the existing literature. Our literature review demonstrates that previous studies have produced inconsistent results, implying this relationship should be re-examined in future work. Impact of higher transparency on users' trust has been insufficiently studied. Current research seems to suggest that the increase of the understanding of privacy issues increases importance of privacy for trust. Use of privacy enhancing mechanisms by service provider also seems to promote the trust, but this may only hold when these mechanisms are understood by the user. A need for tools that would provide users with this kind of knowledge has also been repeatedly recognized. Additionally, this paper provides an overview and description of the currently available transparency enhancing tools. To the best of our knowledge, no such overview has been available to this end. We demonstrate that the majority of tools promote awareness. Most of them attempt to provide a better understanding of privacy policies, or provide insight in the third party tracking behavior. Two tools have been identified that provide some insight in the collected user's data. No tool providing specific information on, or access to, processing logic has been identified. <s> BIB002
Work related to this survey comprises two surveys on PETs and TETs, respectively. Hedbom's BIB001 survey on PETs names the legal stipulations of the European Union as the core principle underlying the necessity of PETs. The classification used in the survey is built on conceptional, socio-structural and technical aspects. The scope is specifically restricted to practical implementations, which includes remote services, stand-alone applications, and browser plug-ins that were available at the time of publishing, but disregards enabler technologies and protocols. Janic et al.'s BIB002 survey on TETs focuses on the aspect of trust. The authors discuss the connection between trust, privacy concern, and transparency. They reflect on how a user's privacy concerns influence her trust in the service she uses, and whether an increase of transparency implies an increased amount of trust. The authors discuss the available publications, and then continue to analyse selected TETs according to the factors previously ascertained in the gathered body of evidence. Hedbom defines transparency in the context of TETs as information about the actual or intended collection, storage, or processing of personal data. Janic et al. define transparency as ''insight in how user's data is being collected, stored, processed and disclosed'' BIB002 . Conversely, this survey considers the term 'transparency' beyond mere conceptional reflection. It aims to answer the question of how exactly individual implementations actually manage to make transparent the processes they were designed for. The design decisions made for the TETs depend on but are not limited to factors such as the stakeholders involved, the environment in which they interact with each other, and the type of device or platform respective TETs operate on. Hedbom as well as Janic et al. briefly discuss the aspect of comprehensibility and usability. Hedbom BIB001 classifies the 'ease of access' as an aspect related to the security requirements of a tool, arguing that tools that are easier to access provide better usability. He attributes comprehensibility in the sense of being easy to understand to a specific type of audience targeted by TETs, namely data subjects in their role as non-professionals. In that regard, that target group's preference for comprehensible information is contrasted by the demands of domain experts whose demands are oriented towards detailed information, which, according to Hedbom, comes at the cost of immediate approachability. Janic et al. BIB002 discuss the aspect of usability explicitly in the context of the comprehensibility of TETs. They hold that comprehensible tools are more likely to support a user's awareness, and are thus more suitable to act as enablers of transparency. However, neither of the two surveys goes into detail about the means by which usability of the reviewed PETs and TETs is achieved, nor whether and how user studies were conducted to test the usability of the respective implementation by the respective target audience. This survey, on the other hand, specifically analyses the means that the reviewed TETs have chosen to achieve usability. The literature research described in Section IV is based on documented methodology, and specifies usability as a key criterion for the screening of the papers. Moreover, the classification scheme presented in this survey in Section V is more detailed and more fine-grained than the ones used in previous surveys and emphasises the connection of its characteristics to the legal and usability principles pointed out in Section II. It comprehends visualisation techniques and usability as a major category of how to meaningfully convey information about disclosed personal data. As such, this survey builds upon and significantly extends and updates the two existing surveys, reviewing contemporary ex post TETs that were discussed in the scientific literature after the aforementioned surveys were published. The contextual scope of this survey is narrower with a fine-grained classification and assessment of ex post TETs compared to the previous surveys, which consider the broader spectrum of PETs and TETs, including ex ante TETs.