Technical solutions for conducting investigations in digital age

Abstract

Confidentiality has always been a concern in secret operation. In this thesis, we consider the situation of legitimate data request and transfer between investigator and database owner who provides intelligence, where the identity of the investigation subject and the records in the database are both confidential. Current practice of secret investigation solely relies on the integrity and carefulness of the involved individuals to resist data leakage, but regulations, policy, agreement, such human means cannot give a promising solution, thus a technical means is needed. As appropriate solution for this confidential data request and transfer problem cannot be found from related research, our goal is to offer a means that can help keeping the investigation secret and protecting irrelevant data at the same time.

We present a technical solution for preserving two-way confidentiality between the investigator (legitimate data requester) and the database owner (legitimate data holder), which can accommodate the concerns of both sides during the specific information request and transfer. Two schemes, Sender-Based Scheme and Receiver-Based Scheme, have been proposed to solve the problem under different conditions, and illustration of executing our schemes is given through an example situation “Investigator and Private hospital” which is an ordinary scenario during investigation. Furthermore, a practical cost reduction methodology on the schemes and sensible proposals for extensions are suggested and discussed. The direction of future work is also considered.