A fresh perspective on covert channels is presented in this work. A new class, air-gap covert channels, is defined as an unintentional communication channel established between systems that are physically and electronically isolated from one another. A specific class of air-gap covert channel is studied in depth, out-of-band covert channels (OOB-CCs), which are defined as policy-breaking communication channels established between isolated, physically unmodified systems. It is shown that OOB-CCs can be categorized by the physical channel that they communicate over: acoustic, light, seismic, magnetic, thermal, and radio-frequency, and the hardware that is required at the transmitter and receiver to make covert communication possible. In general, OOB-CCs are not as high-bandwidth as conventional radio-frequency channels; however, they are capable of leaking sensitive information that requires low data rates to communicate (e.g., text, recorded audio, cryptographic key material). The ability for malware to communicate information using a specific type of OOB-CC, the covert-acoustic channel, is also analyzed. It is empirically demonstrated that using physically unmodified, commodity systems (e.g., laptops, desktops, and mobile devices), covert-acoustic channels can be used to communicate at data rates of hundreds of bits per second, without being detected by humans in the environment, and data rates of thousands of bits per second when nobody is around to hear the communication. Defence mechanisms to counter covert-acoustic channels are also proposed and evaluated, and, as a result, best practices for the designers of secure systems and secure facilities are presented. Additionally, the covertness of OOB-CCs, i.e., the amount of data that can be leaked before the channel is detected, is also determined for classical communication channels as well as for covert-acoustic channels.

Det finns indikationer på att arkitekturen i Sverige upplevs som mer och mer enformig med avsaknad av estetiska kvaliteter. Arkitekter får bära ansvaret för påståendet, men själva menar de att de fråntagits sin ställning i byggprocessen där de byts ut under pågående projekt, underordnade ekonomiska intressen. Målet med arbetet var att ta reda på vad som händer med en byggnads estetiska kvaliteter när arkitekten byts ut samt vad som ligger bakom att bytet sker. En jämförelse mellan två objekt gjordes, ett där arkitekten varit med under hela processen och ett där arkitekten blivit utbytt. Studien utfördes genom faktainsamling från litteratur, observationer och intervjuer. Resultatet visar att viljan att bygga vackert med estetiska kvaliteter är starkt kopplat till beställarens ambitionsnivå. Det sammantagna resultatet visar dock på att estetiska värden underordnas ekonomi i byggprocessen. Vidare har det framkommit under arbetets gång att det råder kunskapsbrist och kommunikationssvårigheter mellan aktörer i byggbranschen, framförallt mellan arkitekt och entreprenör. / There are indications that the architecture in Sweden is perceived as more and more monotonous with the absence of aesthetic qualities. Architects are allowed to bear responsibility for the claim but they themselves believe that they deprived their position in the construction process where they are replaced under ongoing projects, ancillary financial interests. The goal of the work was to find out what happens to a building's aesthetic qualities when the architect is replaced and what lies behind the replacement of the architect. A comparison of two objects was made, one in which the architect has been involved throughout the process and one where the architect has been replaced. The study was conducted through fact-finding from literature, observations and interviews. The result shows that the desire to build beautifully with aesthetic qualities is strongly linked to the client's level of ambition. However, the overall result shows that aesthetic values are subordinated to the economy of the construction-process. Furthermore, it has emerged during the work with this essay that there is a lack of knowledge and difficulties in communication between the actors in the construction industry, especially between architects and contractors.