Is Radiation of Quantized Black Holes Observable?

If primordial black holes (PBH) saturate the present upper limit on the dark matter density in our Solar system and if their radiation spectrum is discrete, the sensitivity of modern detectors is close to that necessary for detecting this radiation. This conclusion is not in conflict with the upper limits on the PBH evaporation rate.Comment: 6 pages, 1 figure (reproduced properly in pdf file

Optimization of the ROCA (CVE-2017-15361) Attack

2017. aastal avastasid Tšehhi teadlased Infineoni loodud RSA võtmete genereerimis algoritmist haavatavuse CVE-2017-15361 (ROCA rünnak). Leiti, et Infineoni algoritmiga genereeritud 2048-bitiseid võtmeid on võimalik faktoriseerida halvimal juhul kõigest 140.8 CPU aastaga. Antud algortimi kasutades olid genereeritud võtmed 750 000 Eesti ID-kaardi jaoks. Selle magistritöö raames implementeeriti ROCA rünnak ning genereeritud võtmeid ja haavatavaid kiipkaarte analüüsides loodi rünnakust uus, optimiseeritud versioon, mille abil on võimalik sooritada rünnak 140.8 aasta asemel 35.2 CPU aastaga 90% võtmete puhul ning 70.4 aastaga ülejäänud võtmetel. Lisaks loodi paralleliseeritud versioon rünnakust kasutades teadusarvutuste klastrit (HPC).In 2017, Czech researchers found the vulnerability CVE-2017-15361 (the ROCA attack) in Infineon's proprietary RSA key generation algorithm. The researchers found that 2048-bit RSA key can be factored in only 140.8 CPU-years in the worst case scenario. The algorithm turned out to be used by 750 000 Estonian ID-cards. In this thesis, we implemented the ROCA attack and, based on the properties observed from the keys generated by the affected smartcards, found further optimizations which allow to improve the original attack from 140.8 CPU-years to 35.2 CPU-years for 90% of the keys and 70.4 CPU-years for the remaining 10% of the keys. As additional contribution, we provide a parallelized version of the attack that can be executed on an HPC

Free space laser telecommunication through fog

Atmospheric clearness is a key issue for free space optical communications (FSO). We present the first active method to achieve FSO through clouds and fog, using ultrashort high intensity laser filaments. The laser filaments opto-mechanically expel the droplets out of the beam and create a cleared channel for transmitting high bit rate telecom data at 1.55 microns. The low energy required for the process allows considering applications to Earth-satellite FSO and secure ground based optical communication, with classical or quantum protocols.Comment: 4 pages + 2 pages supplementary text and movie

Measuring the Cosmic X-ray Background accurately

Measuring the Cosmic X-ray Background (CXB) is a key to understand the Active Galactic Nuclei population, their absorption distribution and their average spectra. However, hard X-ray instruments suffer from time-dependent backgrounds and cross-calibration issues. The uncertainty of the CXB normalization remain of the order of 20%. To obtain a more accurate measurement, the Monitor Vsego Neba (MVN) instrument was built in Russia but not yet launched to the ISS (arXiv:1410.3284). We follow the same ideas to develop a CXB detector made of four collimated spectrometers with a rotating obturator on top. The collimators block off-axis photons below 100 keV and the obturator modulates on-axis photons allowing to separate the CXB from the instrumental background. Our spectrometers are made of 20 mm thick CeBr$_{3}$ crystals on top of a SiPM array. One tube features a $\sim$20 cm$^2$ effective area and more energy coverage than MVN, leading to a CXB count rate improved by a factor of $\sim$10 and a statistical uncertainty $\sim$0.5% on the CXB flux. A prototype is being built and we are seeking for a launch opportunity.Comment: 8 pages, 5 figures, 37th International Cosmic Ray Conference (ICRC2021