Cyber Threat Actors for the Factory of the Future

The increasing degree of connectivity in factory of the future (FoF) environments, with systems that were never designed for a networked environment in terms of their technical security nature, is accompanied by a number of security risks that must be considered. This leads to the necessity of relying on risk assessment-based approaches to reach a sufficiently mature cyber security management level. However, the lack of common definitions of cyber threat actors (CTA) poses challenges in untested environments such as the FoF. This paper analyses policy papers and reports from expert organizations to identify common definitions of CTAs. A significant consensus exists only on two common CTAs, while other CTAs are often either ignored or overestimated in their importance. The identified motivations of CTAs are contrasted with the specific characteristics of FoF environments to determine the most likely CTAs targeting FoF environments. Special emphasis is given to corporate competitors, as FoF environments probably provide better opportunities than ever for industrial espionage if they are not sufficiently secured. In this context, the study aims to draw attention to the research gaps in this area

Cryptography for Human Senses

Cryptography is a key element in establishing trust and enabling services in the digital world. Currently, cryptography is realized with mathematical operations and represented in ways that are not accessible to human users. Thus, humans are left out of the loop when establishing trust and security in the digital world. In many areas the interaction between users and machines is being made more and more seamless and user-friendly, but cryptography has not really enjoyed such development. In this paper, we present ideas that could make cryptography more accessible to humans. We review previous research on this topic and some results that have been achieved. We propose several topics and problems that need to be solved in order to build cryptography for human senses. These measures range from practical implementations of existing methods and utilising a wider range of human senses all the way to building the theoretical foundations of this new form of cryptography

The influence of accretion geometry on the spectral evolution during thermonuclear (type-I) X-ray bursts

Neutron star (NS) masses and radii can be estimated from observations of photospheric radius-expansion X-ray bursts, provided the chemical composition of the photosphere, the spectral colour-correction factors in the observed luminosity range, and the emission area during the bursts are known. By analysing 246 X-ray bursts observed by the Rossi X-ray Timing Explorer from 11 low-mass X-ray binaries, we find a dependence between the persistent spectral properties and the time evolution of the black body normalisation during the bursts. All NS atmosphere models predict that the colour-correction factor decreases in the early cooling phase when the luminosity first drops below the limiting Eddington value, leading to a characteristic pattern of variability in the measured blackbody normalisation. However, the model predictions agree with the observations for most bursts occurring in hard, low-luminosity, &#39;island&#39; spectral states, but rarely during soft, high-luminosity, &#39;banana&#39; states. The observed behaviour may be attributed to the accretion flow, which influences cooling of the NS preferentially during the soft state bursts. This result implies that only the bursts occurring in the hard, low-luminosity spectral states can be reliably used for NS mass and radius determination.</p

The effect of accretion on the measurement of neutron star mass and radius in the low-mass X-ray binary 4U 1608-52

Spectral measurements of thermonuclear (type I) X-ray bursts from low-mass X-ray binaries have been used to measure neutron star (NS) masses and radii. A number of systematic issues affect such measurements and have raised concerns as to the robustness of the methods. We present analysis of the X-ray emission from bursts observed from 4U 1608&minus;52 at various persistent fluxes. We find a strong dependence of the burst properties on the flux and spectral hardness of the persistent emission before burst. Bursts occurring during the low accretion rate (hard) state exhibit evolution of the blackbody normalization consistent with the theoretical predictions of NS atmosphere models. However, bursts occurring during the high accretion rate (soft) state show roughly constant normalization, which is inconsistent with the NS atmosphere models and therefore these bursts cannot be easily used to determine NS parameters. We analyse the hard-state burst to put the lower limit on the NS radius R in 4U 1608&minus;52 of 12 km (for masses 1.0&ndash;2.4 M⊙). We constrain R to be between 13 and 16 km for masses 1.2&ndash;1.6 M⊙. The best agreement with the theoretical NS mass&ndash;radius relations is achieved for source distances in the range 3.1&ndash;3.7 kpc. We expect that the radius limit will be 10 per cent lower if spectral models including rapid rotation are used instead. &nbsp;</p