Towards Realising Post-Quantum Secure ElectionGuard

ElectionGuard is a toolkit used to enable end-to-end verification of elections. Since ElectionGuard uses exponential ElGamal, it is vulnerable to later vote decryption when faced with quantum adversaries. Therefore, to avoid influences on voter behaviour, a post-quantum adaption of ElectionGuard is needed to make the toolkits usage secure for the foreseeable future. In this work, we present cryptographic components that can be used to construct a post-quantum version of ElectionGuard. We use the homomorphic encryption scheme BGV and the commitment scheme BDLOP in a lattice setting. Applying existing and new zero knowledge proofs, we construct the elements needed to show that votes are well-formed and later aggregated correctly. As a final step, we show how to verifiably decrypt the resulting tally. In this paper, we lay the foundation for realising post-quantum secure ElectionGuard. We provide the components for post-quantum vote encryption, aggregation, tallying and verifiable decryption. Our work can be extended by distributed key generation and the components for end-to-end verification

Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant stars VI. First chromosphere model of a late-type giant

Although observational data unequivocally point out to the presence of chromospheres in red giant stars, no attempts have been made so far to model them using 3D hydrodynamical model atmospheres. We therefore compute an exploratory 3D hydrodynamical model atmosphere for a cool red giant in order to study the dynamical and thermodynamic properties of its chromosphere, as well as the influence of the chromosphere on its observable properties. 3D radiation hydrodynamics simulations are carried out with the CO5BOLD model atmosphere code for a star with the atmospheric parameters (Teff=4010 K, log g=1.5, [M/H]=0.0), which are similar to those of the K-type giant star Aldebaran (alpha Tau). ... we compute the emergent continuum intensity maps at different wavelengths, spectral line profiles of Ca II K, the Ca II infrared triplet line at 854.2nm, and H alpha, as well as the spectral energy distribution (SED) of the emergent radiative flux. The initial model quickly develops a dynamical chromosphere characterised by propagating and interacting shock waves. The peak temperatures in the chromospheric shock fronts reach values on the order of up to 5000 K although the shock fronts remain quite narrow. Like for the Sun, the gas temperature distribution in the upper layers is composed of a cool component due to adiabatic cooling in the expanding post-shock regions and a hot component due to shock waves. For this red giant model, the hot component is a rather flat high-temperature tail, which nevertheless affects the resulting average temperatures significantly. The simulations show that the atmospheres of red giant stars are dynamic and intermittent. Consequently, many observable properties cannot be reproduced with one-dimensional static models but demand for advanced 3D HD modelling. Furthermore, including a chromosphere in the models might produce significant contributions to the emergent UV flux.Comment: 14 pages, 8 figures, A&A (2017, accepted

Direct measurement of the nonconservative force field generated by optical tweezers

The force field of optical tweezers is commonly assumed to be conservative, neglecting the complex action of the scattering force. Using a novel method that extracts local forces from trajectories of an optically trapped particle, we measure the three dimensional force field experienced by a Rayleigh particle with 10 nm spatial resolution and femtonewton precision in force. We find that the force field is nonconservative with the nonconservative component increasing radially away from the optical axis, in agreement with the Gaussian beam model of the optical trap. Together with thermal position fluctuations of the trapped particle, the presence of the nonconservative force can cause a complex flux of energy into the optical trap depending on the experimental conditions

Effects of Instrumentality and Personal Force on Deontological and Utilitarian Inclinations in Harm-Related Moral Dilemmas

Moral dilemmas often concern actions that involve causing harm to others in the attempt to prevent greater harm. But not all actions of this kind are equal in terms of their moral evaluation. In particular, a harm-causing preventive action is typically regarded as less acceptable if the harm is a means to achieve the goal of preventing greater harm than if it is a foreseen but unintended side-effect of the action. Likewise, a harm-causing preventive action is typically deemed less acceptable if it directly produces the harm than if it merely initiates a process that brings about the harmful consequence by its own dynamics. We report three experiments that investigated to which degree these two variables, the instrumentality of the harm (harm as means vs. side-effect; Experiments 1, 2, and 3) and personal force (personal vs. impersonal dilemmas; Experiments 2 and 3) influence deontological (harm-rejection) and utilitarian (outcome-maximization) inclinations that have been hypothesized to underly moral judgments in harm-related moral dilemmas. To measure these moral inclinations, the process dissociation procedure was used. The results suggest that the instrumentality of the harm and personal force affect both inclinations, but in opposite ways. Personal dilemmas and dilemmas characterized by harm as a means evoked higher deontological tendencies and lower utilitarian tendencies, than impersonal dilemmas and dilemmas where the harm was a side-effect. These distinct influences of the two dilemma conceptualization variables went undetected if the conventional measure of moral inclinations, the proportion of harm-accepting judgments, was analyzed. Furthermore, although deontological and utilitarian inclinations were found to be largely independent overall, there was some evidence that their correlation depended on the experimental conditions

Errors, fast and slow:An analysis of response times in probability judgments

Based on the Dual-Process Diffusion Model, we tested three hypotheses about response times of errors and correct responses in probability judgments. We predicted that correct responses were (1) slower than errors in the case of conflicting decision processes but (2) faster than errors in the case of alignment; and that they were (3) slower in the case of conflict than in the case of alignment. A binary-choice experiment was conducted in which three types of decision problems elicited conflict or alignment of a deliberative decision process and a heuristic decision process. Consistent with the traditional dual-process architecture, the former captured computational-normative decision strategies and the latter described intuitive-affective aspects of decision making. The hypotheses (1) and (3) were supported, while no statistically significant evidence was found for (2). Implications for the generalisability of the Dual-Process Diffusion Model to slow probability judgments are discussed

A Machine Learning Approach for Automated Fine-Tuning of Semiconductor Spin Qubits

While spin qubits based on gate-defined quantum dots have demonstrated very favorable properties for quantum computing, one remaining hurdle is the need to tune each of them into a good operating regime by adjusting the voltages applied to electrostatic gates. The automation of these tuning procedures is a necessary requirement for the operation of a quantum processor based on gate-defined quantum dots, which is yet to be fully addressed. We present an algorithm for the automated fine-tuning of quantum dots, and demonstrate its performance on a semiconductor singlet-triplet qubit in GaAs. The algorithm employs a Kalman filter based on Bayesian statistics to estimate the gradients of the target parameters as function of gate voltages, thus learning the system response. The algorithm's design is focused on the reduction of the number of required measurements. We experimentally demonstrate the ability to change the operation regime of the qubit within 3 to 5 iterations, corresponding to 10 to 15 minutes of lab-time

Usable Verifiable Secrecy-Preserving E-Voting

In this paper we propose the usage of QR-Codes to enable usable veriable e-voting schemes based on code voting. The idea { from a voter\u27s perspective { is to combine code voting proposed by Chaum with the cast-as-intended verication mechanism used e.g. in Switzerland (using a personal initialization code, return codes per option, a conrmation code and a nalisation code); while all codes to be entered into the e-voting system by voters are available as QR-Code (i.e. one personalised QR voting code per voting option and one personal conrmation QR-Code). We conduct a user study to evaluate the usability and user experience of such an approach: both the code sheets and the election webpage are based on usability research in this area but adopted for our idea. As our proposal performs good wrt. usability, we discuss how such usable front-ends enable more secure e-voting systems in respect to end-to-end veriability and vote secrecy