Low Rank Parity Check codes and their application to cryptography

In this paper we introduce a new family of rank metric codes: the Low Rank Parity Check codes for which we propose an e cient probabilistic decoding algorithm. This family of codes can be seen as the equivalent of classical LDPC codes for the rank metric. We then propose to use these codes for cryptography in the McEliece encryption setting. At the di erence of previous encryption algorithms based on rank metric -especially based on Gabidulin codes -, the codes we use have a very poor structure. Our cryptosystem can be seen as an equivalent to the NTRU cryptosystem [16] (and also to the more recent MDPC[23] cryptosystem) in a rank metric context. Overall our system permits to achieve a very low public key of 1517 bits for a security of 280, moreover our system is very fast, with a decryption failure which can be made arbitrarily small

Measurements of physical parameters characterizing ESDs on solar cell and correlation between spectral signature and discharge position

International audienceElectrostatic discharges on solar cells are possible cause of dramatic consequences such as secondary arcs responsible of definitive power losses. To cope with these significant implications, different approaches are followed such as design rules reducing voltage between adjacent cells, conductive layers or grouting to try to reduce ESDs triggering. However, ESDs on solar cells cannot be completely avoided and having a good knowledge of their characteristics is essential for prevention, prediction and modelling. In this paper, we describe how the plasma emitted during an electrostatic discharge on solar cell can be analyzed with dynamic tools such as triple probes and time-resolved optical spectroscopy. These techniques are used to obtain results on plasma density and electron temperature that can be compared with outputs from ESDs and flashover propagation models. While time-resolved optical spectroscopy is used on a single point (the point where optical fiber is focused on), triple probe is also used for spatial measurements. With this technique, electron density is measured at several distances from the discharge point providing both temporal and spatial information. In a second time, the optical signature measured by optical spectroscopy is correlated with SEM observations showing the existence of two kinds of triple points at the cell's edge. These two kinds of discharges have different optical signatures showing either elements from the active junction or from the substrate and rear electrode. These discharges are also distinguished by SEM observations and images of cell's edges confirm the previous results. These results show the importance of the silver back electrode and also of the eventual presence of covering glue on the position of the discharge. They provide information for models but let us also imagine possible mitigation methods

Mortality reduction by post-dilution online-haemodiafiltration : A cause-specific analysis

Background. From an individual participant data (IPD) meta-analysis from four randomized controlled trials comparing haemodialysis (HD) with post-dilution online-haemodiafiltration (ol-HDF), previously it appeared that HDF decreases all-cause mortality by 14% (95% confidence interval 25; 1) and fatal cardiovascular disease (CVD) by 23% (39; 3). Significant differences were not found for fatal infections and sudden death. So far, it is unclear, however, whether the reduced mortality risk of HDF is only due to a decrease in CVD events and if so, which CVD in particular is prevented, if compared with HD. Methods. The IPD base was used for the present study. Hazard ratios and 95% confidence intervals for cause-specific mortality overall and in thirds of the convection volume were calculated using the Cox proportional hazard regression models. Annualized mortality and numbers needed to treat (NNT) were calculated as well. Results. Besides 554 patients dying from CVD, fatal infections and sudden death, 215 participants died from 'other causes', such as withdrawal from treatment and malignancies. In this group, the mortality risk was comparable between HD and ol-HDF patients, both overall and in thirds of the convection volume. Subdivision of CVD mortality in fatal cardiac, non-cardiac and unclassified CVD showed that ol-HDF was only associated with a lower risk of cardiac casualties [0.64 (0.61; 0.90)]. Annual mortality rates also suggest that the reduction in CVD death is mainly due to a decrease in cardiac fatalities, including both ischaemic heart disease and congestion. Overall, 32 and 75 patients, respectively, need to be treated by high-volume HDF (HV-HDF) to prevent one all-cause and one CVD death, respectively, per year. Conclusion. The beneficial effect of ol-HDF on all-cause and CVD mortality appears to be mainly due to a reduction in fatal cardiac events, including ischaemic heart disease as well as congestion. In HV-HDF, the NNT to prevent one CVD death is 75 per year

Mortality reduction by post-dilution online-haemodiafiltration : A cause-specific analysis

Background. From an individual participant data (IPD) meta-analysis from four randomized controlled trials comparing haemodialysis (HD) with post-dilution online-haemodiafiltration (ol-HDF), previously it appeared that HDF decreases all-cause mortality by 14% (95% confidence interval 25; 1) and fatal cardiovascular disease (CVD) by 23% (39; 3). Significant differences were not found for fatal infections and sudden death. So far, it is unclear, however, whether the reduced mortality risk of HDF is only due to a decrease in CVD events and if so, which CVD in particular is prevented, if compared with HD. Methods. The IPD base was used for the present study. Hazard ratios and 95% confidence intervals for cause-specific mortality overall and in thirds of the convection volume were calculated using the Cox proportional hazard regression models. Annualized mortality and numbers needed to treat (NNT) were calculated as well. Results. Besides 554 patients dying from CVD, fatal infections and sudden death, 215 participants died from 'other causes', such as withdrawal from treatment and malignancies. In this group, the mortality risk was comparable between HD and ol-HDF patients, both overall and in thirds of the convection volume. Subdivision of CVD mortality in fatal cardiac, non-cardiac and unclassified CVD showed that ol-HDF was only associated with a lower risk of cardiac casualties [0.64 (0.61; 0.90)]. Annual mortality rates also suggest that the reduction in CVD death is mainly due to a decrease in cardiac fatalities, including both ischaemic heart disease and congestion. Overall, 32 and 75 patients, respectively, need to be treated by high-volume HDF (HV-HDF) to prevent one all-cause and one CVD death, respectively, per year. Conclusion. The beneficial effect of ol-HDF on all-cause and CVD mortality appears to be mainly due to a reduction in fatal cardiac events, including ischaemic heart disease as well as congestion. In HV-HDF, the NNT to prevent one CVD death is 75 per year