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Niklas Pauli:

Redesigning the user interface of an application for managing open-source security hardware


  • Programming language: Python
  • Framework: Qt5
Human-Centered Design Process, User Interface Design, Crossplattform App, Software Engineering
Bachelor of Science (B.Sc.)



This work is based on literature from the field of human-computer interaction, as the emphasis is on improving usability and user experience. Thematically, the approach is based on the lecture "Human-Computer Interaction 1" by Prof. Dr. Claudia Müller-Birn.

The work consists of the analysis of requirements for the user interface, the design based on this analysis, and the evaluation of the result.


Nitrokey GmbH is the world's leading company for open-source security hardware.

Nitrokey offers IT security hardware for a wide range of services, including data encryption, key management, and user authentication. To make it easier to use Nitrokey devices, a simple app has been developed. As the user interface is the communication link between the program and the user, the users must be able to intuitively understand and use the user interface. Especially in IT security

it is of crucial importance to offer users comprehensible interaction options. In this bachelor thesis, the graphical user interface of the Nitrokey app will be adjusted to the needs of the users to increase usability and user experience.


The aim of this work is to adapt the graphical user interface of the Nitrokey app more appropriately to the needs of the users. The objective is not only to improve existing functions, but also to identify and add missing ones. In addition, a prototype will be programmed. This will be the basis for the new user interface of the Nitrokey app and will be used for the qualitative evaluation.


By applying the human-centered design process, analysis, design and evaluation, a concept for the new user interface will be developed.

The resulting user interface is implemented in Python and finally evaluated.

1. Data gathering / Analysis

  • Current GUI
  • User documentation and instructions
  • User Feedback /Issue Tickets
  • Related software
  • Focus group
    • User interface requirements

2. Design /Implementation

  • Low fidelity prototype
  • High fidelity prototype
    • Testable prototype

3. Evaluation

  • Qualitative study
    • Evaluation of the user interface to determine strengths and weaknesses


H. Sharp, J. Preece. Y. Rogers. Interaction Design - beyond human-computer interaction. 5. Edition, 2019.

D. Kadavy. Design for Hackers Reverse Engineering Beauty, 2011.

W. Galitz. The Essential Guide to User Interface Design. An Introduction to GUI

Design Principles and Techniques, 2007.

J. Tidwell. Designing Interfaces. Patterns for Effective Interaction Design. 2. Edition, 2011.

M. A. A. Majid, M. Othman, S. F. Mohamad, S. A. H. Lim, A. Yusof: Piloting for Interviews in Qualitative Research. Operationalization and Lessons Learnt, 2017.

D. Norman, J. Nielsen. 10 Usability Heuristics for User Interface Design, 2020.