Digital forensics is a branch of forensic science that is focused on investigation of data found in digital devices in relation to cybercrime. It has become a critical aspect of modern law enforcement investigations. The significance of digital forensics has been highlighted in paragraph 256 of the Explanatory Report to the Council of Europe Convention on Cybercrime as it has been pointed out that digital data is highly volatile. Besides being able to ‘move’ really fast, digital data is also fragile. Namely, any weak link in the digital ‘chain of custody’ can have a detrimental impact upon the data’s integrity and reliability. Digital forensics requires certain expertise that goes beyond traditional methods of data collection.

In order for digital evidence to be accepted in court, it has to be handled in a specific way. There are five steps of digital forensics such as identification, preservation, analysis, documentation, and presentation. The complexity behind digital forensics imposes challenges to the right to a fair trial and the scientific validity of digital data gathered during the investigation. A number of legal scholars examined impact of the inappropriate use of investigative technology in relation to essential legal principles, such as the presumption of innocence. Furthermore, the need for data retention for the purposes of investigation has been recognized widely by law enforcement, yet it has been questioned and criticised due to its controversial nature. For instance, in the Tele2Sverige case (Joined cases C-203/15 and 698/15, CJEU), the Court of Justice of the EU held that a general requirement for collection of traffic and location data by all service providers for the purpose of combating crime was not compliant with the EU data protection legislation.

On the EU level, the processing of large-scale digital evidence in criminal investigations falls within the scope of the so-called Police Directive (2016/680) that has entered into force in 2016. year. The main aim of this Directive is to safeguard individuals’ personal data that is being processed for the purposes of investigation or prosecution of criminal offences. Nevertheless, digital forensics will continue to develop as a highly valuable tool in criminal investigations. This scientific branch poses a number of challenges due to rapidly changing technologies and legal issues, specifically in relation to the admission of digital evidence in courts.