Transparency of personal data processing is enforced by most Western privacy laws, including the new General Data Protection Regulation (GDPR) which will be effective from May 2018. The GDPR specifies that personal data shall be processed lawfully, fairly, and in a transparent manner. It strengthens people's rights for both ex-ante and ex-post transparency and intervenability. Equally important is the strict legal requirements for informed consent established by the GDPR.

On the other hand, the legal privacy principles have Human-Computer Interaction (HCI) implications. People should comprehend the principles, be aware of when the principles may be used, and be able to use them. Transparent information about personal data processing should be concise, intelligible, and provided in an easily accessible form, pursuant to the GDPR. Nonetheless, the answer to the question about how HCI implications can be addressed depends on the attempts to decrease the gap between legal and user-centric transparency, intervenability, and consent. Enhancing individuals' control in a usable way helps people to be aware of the flow of their personal information, control their data, make informed decisions, and finally preserve their privacy.

The objective of this thesis is to propose usable tools and solutions, to enhance people's control and enforce legal privacy principles, especially transparency, intervenability, and informed consent. To achieve the goal of the thesis, different ways to improve ex-ante transparency and informed consent are investigated by designing and testing new solutions to make effective consent forms. Moreover, ex-post transparency and intervenability are improved by designing a transparency enhancing tool and investigating users' perceptions of data portability and transparency in the tool. The results of this thesis contribute to the body of knowledge by mapping legal privacy principles to HCI solutions, unveiling HCI problems and answers when aiming for legal compliance, and proposing effective designs to obtain informed consent.    

The new General Data Protection Regulation (GDPR) strengthens people’s rights for transparency, intervenability, and consent. The legal privacy principles have Human-Computer Interaction (HCI) implications. Besides aiming for legal compliance, it is of paramount importance to investigate how to provide individuals with usable and user-centric transparency, intervenability, and consent.

The objective of this thesis is to propose usable tools and solutions, to enhance people's control and enforce legal privacy principles, especially transparency, intervenability, and informed consent. To achieve the goal of the thesis, different ways to improve ex-ante transparency and informed consent are investigated by designing and testing new solutions to make effective consent forms. Moreover, ex-post transparency and intervenability are improved by designing a transparency enhancing tool and investigating users' perceptions of data portability and transparency in the tool. The results of this thesis contribute to the body of knowledge by mapping legal privacy principles to HCI solutions, unveiling HCI problems and answers when aiming for legal compliance, and proposing effective designs to obtain informed consent.