Extortion using digital platforms is an increasing form of crime. A commonly seen problem is extortion in the form of an infection of a Crypto Ransomware that encrypts the files of the target and demands a ransom to recover the locked data. By analyzing the four most common Crypto Ransomwares, at writing, a clear vulnerability is identified; all infections rely on tools available on the target system to be able to prevent a simple recovery after the attack has been detected. By renaming the system tool that handles shadow copies it is possible to recover from infections from all four of the most common Crypto Ransomwares. The solution is packaged in a single, easy to use script.

A new method for musical steganography for the MIDI format is presented. The MIDI standard is a user-friendly music technology protocol that is frequently deployed by composers of different levels of ambition. There is to the author’s knowledge no fully implemented and rigorously specified, publicly available method for MIDI steganography. The goal of this study, however, is to investigate how a novel MIDI steganography algorithm can be implemented by manipulation of the velocity attribute subject to restrictions of capacity and security. Many of today’s MIDI steganography methods—less rigorously described in the literature—fail to be resilient to steganalysis. Traces (such as artefacts in the MIDI code which would not occur by the mere generation of MIDI music: MIDI file size inflation, radical changes in mean absolute error or peak signal-to-noise ratio of certain kinds of MIDI events or even audible effects in the stego MIDI file) that could catch the eye of a scrutinizing steganalyst are side-effects of many current methods described in the literature. This steganalysis resilience is an imperative property of the steganography method. However, by restricting the carrier MIDI files to classical organ and harpsichord pieces, the problem of velocities following the mood of the music can be avoided. The proposed method, called Velody 2, is found to be on par with or better than the cutting edge alternative methods regarding capacity and inflation while still possessing a better resilience against steganalysis. An audibility test was conducted to check that there are no signs of audible traces in the stego MIDI files.

This study describes a new method for musical steganography utilizing the MIDI format. MIDI is a standard music technology protocol that is used around the world to create music and make it available for listening. Since no publicly available method for MIDI steganography has been found (even though there are a few methods described in the literature), the study investigates how a new algorithm for MIDI steganography can be designed so that it satisfies capacity and security criteria. As part of the study, a method for using velocity values to hide information in music has been designed and evaluated, during which the capacity of the method is found to be comparable with similar methods. In an audibility test, it is observed that audible impact on the music can not be distinguished at any reasonable significance level, which means that also a security criterion is met.

The rapid growth of distributed real-time systems creates a need for cheap and available network solutions while still fulfilling the real-time requirements. In this paper we propose a method for less pessimistic delay analysis for packet switched first come first serve network, when knowing the intervals of possible message generation. Experiments show that the proposed method generates the expected results according to theoretical limitations of the experiment cases. The experiments also show that the proposed method could be practically used for non-trivial systems. Suggestions are given for future work on how to relax traffic requirements and how to cope with circular dependencies.