Usalduse vähendamine ja turvalisuse parandamine zk-SNARK-ides ja kinnitusskeemides

Väitekirja elektrooniline versioon ei sisalda publikatsioonezk-SNARK-id on tõhusad ja praktilised mitteinteraktiivsed tõestussüsteemid, mis on konstrueeritud viitestringi mudelis ning tänu kompaktsetele tõestustele ja väga tõhusale verifitseeritavusele on need laialdaselt kasutusele võetud suuremahulistes praktilistes rakendustes. Selles töös uurime zk-SNARK-e kahest vaatenurgast: nende usalduse vähendamine ja turvalisuse tugevdamine. Esimeses suunas uurime kui palju saab vähendada usaldust paaristuspõhiste zk-SNARK-ide puhul ilma nende tõhusust ohverdamata niiviisi, et kasutajad saavad teatud turvataseme ka siis kui seadistusfaas tehti pahatahtlikult või kui avalikustati seadistusfaasi salajane teave. Me pakume välja mõned tõhusad konstruktsioonid, mis suudavad takistada zk-SNARK-i seadistusfaasi ründeid ja mis saavutavad senisest tugevama turvataseme. Näitame ka seda, et sarnased tehnikad võimaldavad leevendada usaldust tagauksega kinnitusskeemides, mis on krüptograafiliste primitiivide veel üks silmapaistev perekond ja mis samuti nõub usaldatud seadistusfaasi. Teises suunas esitame mõned tõhusad konstruktsioonid, mis tagavad parema turvalisuse minimaalsete lisakuludega. Mõned esitatud konstruktsioonidest võimaldavad lihtsustada praegusi TK-turvalisi protokolle, nimelt privaatsust säilitavate nutilepingusüsteemide Hawk ja Gyges konstruktsiooni, ja parandada nende tõhusust. Uusi konstruktsioone saab aga otse kasutada uutes protokollides, mis soovivad kasutada zk-SNARK-e. Osa väljapakutud zk-SNARK-e on implementeeritud teegis Libsnark ja empiirilised tulemused kinnitavad, et usalduse vähendamiseks või suurema turvalisuse saavutamiseks on arvutuslikud lisakulud väikesed.Zero-knowledge Succinct Non-interactive ARguments of Knowledge (zk-SNARKs) are an efficient family of NIZK proof systems that are constructed in the Common Reference String (CRS) model and due to their succinct proofs and very efficient verification, they are widely adopted in large-scale practical applications. In this thesis, we study zk-SNARKs from two perspectives, namely reducing trust and improving security in them. In the first direction, we investigate how much one can mitigate trust in pairing-based zk-SNARKs without sacrificing their efficiency. In such constructions, the parties of protocol will obtain a certain level of security even if the setup phase was done maliciously or the secret information of the setup phase was revealed. As a result of this direction, we present some efficient constructions that can resist against subverting of the setup phase of zk-SNARKs and achieve a certain level of security which is stronger than before. We also show that similar techniques will allow us to mitigate the trust in the trapdoor commitment schemes that are another prominent family of cryptographic primitives that require a trusted setup phase. In the second direction, we present some efficient constructions that achieve more security with minimal overhead. Some of the presented constructions allow to simplify the construction of current UC-secure protocols and improve their efficiency. New constructions can be directly deployed in any novel protocols that aim to use zk-SNARKs. Some of the proposed zk-SNARKs are implemented in Libsnark, the state-of-the-art library for zk-SNARKs, and empirical experiences confirm that the computational cost to mitigate the trust or to achieve more security is practical.https://www.ester.ee/record=b535927

Classification of Primary versus Metastatic Pancreatic Tumor Cells Using Multiple Biomarkers and Whole Slide Imaging

Pancreatic cancer is a challenging cancer with a high mortality rate and a 5-year survival rate between 2% to 9%. The role of biomarkers is crucial in cancer prognosis, diagnosis, and predicting the possible responses to a specific therapy. The Discovery and development of various types of biomarkers have been studied intensively in the hope of determining the best treatment approaches, better management, and possibly cure of this deadly cancer. However, metastasis, responsible for about 90% of the deaths from cancer, is still poorly understood. A few research that have investigated the expression of a particular biomarker or a panel of biomarkers in the primary and secondary (metastatic) tumor demonstrates that the expression of different biomarkers in the primary and secondary tumor sites is not necessarily the same, even though the primary and metastatic tumor cells are originated from the same organ. In this project, we aim to design a classifier to distinguish between primary and secondary tumor cells based on their uptake of different biomarkers, using immunofluorescence whole slide imaging. For this purpose, we first register consecutive images of the same slide together to be able to locate multiple biomarkers that belong to a cell and later we design our classifier based on vectors that show the presence or absence of multiple antibodies in addition to the amount of that antibody in a tumor cell. Advisor: Khalid Sayoo

A Content Analysis of Colour-term Conceptual Metaphors in Modern Persian Poetry

This study sought answers related to the distribution of colour terms in Persian poems and their metaphoric reflection in poets' beliefs, ideas, or values. In so doing, 137 Persian verses from two poetry books with colour terms in content were considered for the analysis. Four raters who studied literature of Persian scrutinized the verses for the evaluation of the colour metaphoric conceptualizations. To validate the raters' suggestions, a focus group of sixteen commented on the recommended connotations. Results indicated that colours are not similarly distributed in Persian poems, are used with different conceptualizations and stood for both positive and negative connotations. Therefore, since colours are part of the authors' and speakers' daily lives to express information, knowledge of metaphoric expressions is suggested to be an inseparable part of language classes

Sulfonated organic heteropolyacid salts as a highly efficient and green solid catalysts for the synthesis of 1,8-dioxo-decahydroacridine derivatives in water

AbstractIn the present study, we introduce two nonconventional ionic liquids [MIMPS]3PW12O40 (a) and [TEAPS]3PW12O40 (b) as green and highly efficient solid acid catalysts for the synthesis of 1,8-dioxo-decahydroacridine derivatives. The one-pot three component reaction of 1,3-cyclohexanediones, aromatic aldehydes and aromatic amines or ammonium acetate in water afforded the corresponding 1,8-dioxo-decahydroacridines in excellent yields. This reaction has been carried out in the presence of 1mol% of catalysts at room temperature. The reusability of the catalysts was demonstrated by a five-run test. Additionally, the catalysts pose several advantages including mild reaction conditions, cleaner reactions and shorter reaction times

Study of Antibacterial Activity of Ethylacetate Total Extract and the Alkaloid Fraction from Flowering Aerial Parts of Glaucium vitellinum Boiss. et Buhse against Clinical Isolates of Staphylococcus Spp.

Background: The purpose of this study was evaluation of the antimicrobial effect of ethyl acetate extract and alkaloid fraction of Glaucium vitellinum (G. vitellinum) against clinical Staphylococcus spp. isolates from patients of Sina hospital of Tehran.Materials and Methods: The plant of G. vitellinum was collected from Khonsar, Isfahan province, during May 2014. It’s flowering and aerial parts were washed, dried, powdered and extracted with methanol and ethyl acetate by using percolator apparatus, separately. In continuation, the alkaloid fraction was separated from metanolic total extract. 100 clinical isolates of Staphylococcus spp. were collected randomly from different clinical samples of patients who referred to Sina hospital of Tehran during 2013-2014. Also, their resistant to common antibiotics were evaluated by disk diffusion method based on the CLSI 2014 protocol. Continuously, the antibacterial effect of ethyl acetate total extract and the alkaloid fraction against clinical isolates of Staphylococcus spp. were evaluated by determining the minimal inhibitory concentration (MIC) by microdilution method based on the CLSI 2014. Standard Staphylococcus aureus (PTCC1431) and Staphylococcus epidermidis (PTCC 1435) were evaluated, simultaneously.Results: Based on the results, 93% of isolates were coagulase positive and 7% were coagulase negative Staphylococci spp. (CoNS). All coagulase positive cocci were identified as Staphylococcus aureus and among 7% CoNS, 3% were identified as S. epidermidis, so, in the follow they are named only CoNS.The MIC of alkaloid fraction of G.vitellinum was: 17.87 mg/ml and 23.21 mg/ml against coagulase positive S.aureus and CoNS isolates, respectively. Also, MIC of ethyl acetate total extract of G.vitellinum was: 73.25 mg/ml and 98.21mg/ml on coagulase positive S. aureus and CoNS isolates, respectively.61.29% of clinical S. aureus isolates were sensitive to ethyl acetate total extract  and 100 % were sensitive to alkaloid fraction while 100% were penicillin resistant while only 60%  of them were Trimethoprim/sulfamethoxazole (SXT) sensitive.Similarly, among CoNS isolates, 42.85% and 100% were sensitive to ethyl acetate total extract and alkaloid fraction, respectively. While 100% were penicillin resistant and only 42%were ciprofloxacin and doxycycline sensitivity.Conclusion: based on the existence of good antibacterial effect for alkaloid portion of G. vitellinum against clinical isolates of Staphylococcus spp. doing other in vitro and in vivo complementation tests are recommended for the further studies. Keyword: Glaucium vitellinum, Anti bacterial, Alkaloids, Papaveraceae

Etiology of acute scrotal pain in children and adolescent patients admitted in Ahvaz Educational Hospitals

Purpose Acute scrotum is an emergency condition requiring rapid intervention. The aim of this study was to evaluate the clinical and epidemiological specifications of acute scrotum.Patients and methods This retrospective study was carried out on patients less than 21 years admitted with a diagnosis of acute scrotum in the surgical and medical wards from 2009 to 2010. One hundred and thirty-nine patients were included in this study. Epi-info version 6.4 (CDC) was used for data analysis.Results The final diagnoses were as follows: spermatic cord torsion (n =57, 41.00%), incarcerated inguinal hernia (n =30, 21.60%), epididymo-orchitis (n= 28, 20.14%), missed torsion (n =15, 10.79%), testicular trauma (n=5, 3.60%), and torsion of the appendix of the testis (n= 4, 2.87%). The most common age groups in relation to the diagnoses were as follows: testicular torsion and missed torsion (10–15 years, 34.7%), torsion of appendix testis (10–15 years, 100%), epididymo-orchitis (15–21 years, 85.71%), and incarcerated inguinal hernia with two peaks of age ( <5 years, 46.7%). Fifty-eight patients (41.72%) visited the hospital less than 6 h after the onset of pain. Twenty-eight patients underwent orchiectomy or orchiopexy and 38 patients underwent detorsion and bilateral orchiopexy. A herniotomy was performed in 15 patients and herniorraphy in 10 patients. An appendectomy was performed in four patients. Other procedures were carried out in seven patients. Out of 72 patients diagnosed with torsion (57 patients) or missed torsion (15 patients), 38 patients (52.7%) underwent a testicular salvage surgery (detorsion and orchiopexy). Out of all patients (139 patients), 92 patients underwent surgery and the rest (47 patients) were treated conservatively. These 47 patients had epididymo-orchitis (n= 28), testicular trauma (n =4), incarcerated inguinal hernia (n= 5), and missed torsion and testicular torsion (n= 10). Out of 27 patients with abnormal urinary findings, 19 patients had epididymo-orchitis.Conclusion The most common important differential diagnosis for acute scrotum is spermatic cord torsion. Most of the abnormal urinary findings were observed in patients with epididymo-orchitis. Most of the patients underwent surgery less than 6 h of disease onset. In patients with spermatic cord torsion, the affected testis has to be evaluated and treated during the first 6 h of presentation.Keywords: epididymitis, epididymo-orchitis, herniotomy, hydrocele, inguinal hernia, orchiopexy, scrotum, testicular torsion, traum

Boosting terahertz-radiation power with two-color circularly polarized midinfrared laser pulses

A way to considerably enhance terahertz radiation, emitted in the interaction of intense midinfrared laser pulses with atomic gases, in both the total energy and the electric-field amplitude is suggested. The scheme is based on the application of a two-color field consisting of a strong circularly polarized midinfrared pulse with wavelengths of 1.6-4 mu m and its linearly or circularly polarized second harmonic of lower intensity. By combining the strong-field approximation for the ionization of a single atom with particle-in-cell simulations of the collective dynamics of the generated plasma, it is shown that the application of such two-color circularly polarized laser pulses may lead to an order-of-magnitude increase in the energy emitted in the terahertz frequency domain as well as in a considerable enhancement in the maximal electric field of the terahertz pulse. Our results support recently reported experimental and numerical finding

Tiramisu: Black-Box Simulation Extractable NIZKs in the Updatable CRS Model

Zk-SNARKs, as the most efficient NIZK arguments in terms of proof size and verification, are ubiquitously deployed in practice. In applications like Hawk [S&P\u2716], Gyges [CCS\u2716], Ouroboros Crypsinous [S&P\u2719], the underlying zk-SNARK is lifted to achieve Black-Box Simulation Extractability (BB-SE) under a trusted setup phase. To mitigate the trust in such systems, we propose $\texttt{Tiramisu}$, as a construction to build NIZK arguments that can achieve $\textit{updatable BB-SE}$, which we define as a new variant of BB-SE. This new variant allows $\textit{updating}$ the public parameters, therefore eliminating the need for a trusted third party, while unavoidably relies on a $\textit{non-black-box}$ extraction algorithm in the setup phase. In the cost of one-time individual CRS update by the parties, this gets around a known impossibility result by Bellare et al. from ASIACRYPT\u2716, which shows that BB extractability cannot be achieved with subversion ZK (ZK without trusting a third party). $\texttt{Tiramisu}$ uses an efficient public-key encryption with updatable keys which may be of independent interest. We instantiate $\texttt{Tiramisu}$, implement the overhead, and present efficient BB-SE zk-SNARKs with updatable parameters that can be used in various applications while allowing the end-users to update the parameters and eliminate the needed trust