Scientific development and progress in the fields of computer science, information technology and their related disciplines, have transformed our world into a “digital world”. Omnipresent digital devices and e-services running on numerous versions of pervasive e-infrastructures generate a wealth of electronically stored information (ESI) from which we can extract a great deal of potential digital evidence.
Digital evidence is sometimes even more revealing than its traditional counterpart, but at the same time it is very fragile and volatile in nature. Preserving the integrity of digital evidence is therefore of major concern, especially when it comes from purportedly illegal, illicit and malicious activities. The acquisition and analysis of digital evidence are also crucial to the functioning of the digital world, regardless of the positive or negative implications of the actions and activities that generated the evidence. All stakeholders should have the right to be assured of the accuracy of the digital forensics process and the people involved in it. Currently they surrender these rights and have to trust the process and the individuals carrying it out. They do not have any guarantee that intentional or unintentional conduct or modification will not affect the outcome of the forensic process, which might compromise their other human rights as a consequence, such as their right to liberty and even their right to life. Protecting basic human rights by ensuring the correctness of the entire forensics process, and its output in the form of digital evidence, is thus a point of concern. The “right to a fair trial” given in Article 6 of the European Convention as an umbrella principle that affects the forensics process, is one example of the protection of basic human rights.
In digital forensics there are principles and models on the top (theoretical basis), acting as a platform on abstract and generic level, in the middle, there are policies and practices and at the bottom, there are technical procedures and techniques. During this research we worked to solve the above mentioned problems, concentrating on all three layers, by extending the abstract models, defining best practice, and by providing new technical procedures employing latest technology. Our work also helps to implement organisational policies.
The research was undertaken in two cycles, starting with an exploration of the theoretical basis and continuing to procedures and techniques. The methods used to preserve the integrity of digital evidence were explored and evaluated in the first cycle. A new technical model called PIDESC was thus proposed. This can preserve the integrity of digital evidence by orchestrating both software- and hardware-based security solutions. The model was evaluated in terms of time and cost. The results suggest that the gains outweigh the additional cost and time. The increase in time is a constant negligible factor of only half a millisecond on average. In the next cycle we built on our knowledge and extended the theoretical basis on an abstract and generic level to preserve the integrity of digital evidence and to protect basic human rights as overarching umbrella principles (2PasU). We then developed specific solutions, including a formal method to select the best mobile device forensics tool, and developed a guide for best practices to fulfil the requirements of preservation and protection. Finally, we mapped the solutions to the proposed extended model with 2PasU, putting all the research into its context in order to pave the way for future work in this domain.
 Protecting Digital Evidence Integrity by Using Smart Cards
 Preservation and Protection as Umbrella Principles
Stockholm: Department of Computer and Systems Sciences, Stockholm University , 2015. , 116 p.
At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 6: Submitted.