Foundations and applications of program obfuscation

Code is said to be obfuscated if it is intentionally difficult for humans to understand. Obfuscating a program conceals its sensitive implementation details and protects it from reverse engineering and hacking. Beyond software protection, obfuscation is also a powerful cryptographic tool, enabling a variety of advanced applications. Ideally, an obfuscated program would hide any information about the original program that cannot be obtained by simply executing it. However, Barak et al. [CRYPTO 01] proved that for some programs, such ideal obfuscation is impossible. Nevertheless, Garg et al. [FOCS 13] recently suggested a candidate general-purpose obfuscator which is conjectured to satisfy a weaker notion of security called indistinguishability obfuscation. In this thesis, we study the feasibility and applicability of secure obfuscation: - What notions of secure obfuscation are possible and under what assumptions? - How useful are weak notions like indistinguishability obfuscation? Our first result shows that the applications of indistinguishability obfuscation go well beyond cryptography. We study the tractability of computing a Nash equilibrium vii of a game { a central problem in algorithmic game theory and complexity theory. Based on indistinguishability obfuscation, we construct explicit games where a Nash equilibrium cannot be found efficiently. We also prove the following results on the feasibility of obfuscation. Our starting point is the Garg at el. obfuscator that is based on a new algebraic encoding scheme known as multilinear maps [Garg et al. EUROCRYPT 13]. 1. Building on the work of Brakerski and Rothblum [TCC 14], we provide the first rigorous security analysis for obfuscation. We give a variant of the Garg at el. obfuscator and reduce its security to that of the multilinear maps. Specifically, modeling the multilinear encodings as ideal boxes with perfect security, we prove ideal security for our obfuscator. Our reduction shows that the obfuscator resists all generic attacks that only use the encodings' permitted interface and do not exploit their algebraic representation. 2. Going beyond generic attacks, we study the notion of virtual-gray-box obfusca- tion [Bitansky et al. CRYPTO 10]. This relaxation of ideal security is stronger than indistinguishability obfuscation and has several important applications such as obfuscating password protected programs. We formulate a security requirement for multilinear maps which is sufficient, as well as necessary for virtual-gray-box obfuscation. 3. Motivated by the question of basing obfuscation on ideal objects that are simpler than multilinear maps, we give a negative result showing that ideal obfuscation is impossible, even in the random oracle model, where the obfuscator is given access to an ideal random function. This is the first negative result for obfuscation in a non-trivial idealized model

Triazole-Based Compound as a Candidate To Develop Novel Medicines To Treat Toxoplasmosis

This article reports anti-Toxoplasma gondii activity of 3-(thiophen-2-yl)-1,2,4-triazole-5-thione. The compound displayed significant and reproducible antiparasitic effects at nontoxic concentrations for the host cells, with an experimentally determined 50% inhibitory concentration (IC50) at least 30 times better than that of the known chemotherapeutic agent sulfadiazine. Purine nucleoside phosphorylase was defined as the probable target for anti-Toxoplasma activity of the tested compound. These results provide the foundation for future work to develop a new class of medicines to better treat toxoplasmosis

A DFT and ONIOM study of C–H hydroxylation catalyzed by nitrobenzene 1,2-dioxygenase

A detailed description of the mechanism of C–H hydroxylation by Rieske non-heme iron dioxygenases remains elusive, as the nature of the oxidizing species is not definitively known. DFT calculations on cluster models of nitrobenzene 1,2-dioxygenase were done to explore possible mechanisms arising from oxidation by either the experimentally observed FeIII–OOH complex or the putative high-valent HO–FeVQO intermediate formed through a heterolytic O–O bond cleavage. Hydrogen abstraction by HO–FeVQO, followed by oxygen rebound, was found to be consistent with experimental studies. The findings from the quantum mechanical cluster approach were verified by accounting for the effect of the protein environment on transition state geometries and reaction barriers through ONIOM calculations

1,4-disubstituted thiosemicarbazide derivatives are potent inhibitors of toxoplasma gondii proliferation.

A series of 4-arylthiosemicarbazides substituted at the N1 position with a 5-membered heteroaryl ring was synthesized and evaluated in vitro for T. gondii inhibition proliferation and host cell cytotoxicity. At non-toxic concentrations for the host cells all studied compounds displayed excellent anti-parasitic effects when compared to sulfadiazine, indicating a high selectivity of their anti-T. gondii activity. The differences in bioactivity investigated by DFT calculations suggest that the inhibitory activity of 4-arylthiosemicarbazides towards T. gondii proliferation is connected with the electronic structure of the molecule. Further, these compounds were tested as potential antibacterial agents. No growth-inhibiting effect on any of the test microorganisms was observed for all the compounds, even at high concentrations

Influence of Association on Binding of Disaccharides to YKL-39 and hHyal-1 Enzymes

Disaccharide complexes have been shown experimentally to be useful for drug delivery or as an antifouling surface biofilm, and are promising drug-encapsulation and delivery candidates. Although such complexes are intended for medical applications, to date no studies at the molecular level have been devoted to the influence of complexation on the enzymatic decomposition of polysaccharides. A theoretical approach to this problem has been hampered by the lack of a suitable computational tool for binding such non-covalent complexes to enzymes. Herein, we combine quantum-mechanical calculations of disaccharides complexes with a nonstandard docking GaudiMM engine that can perform such a task. Our results on four different complexes show that they are mostly stabilized by electrostatic interactions and hydrogen bonds. This strong non-covalent stabilization demonstrates the studied complexes are some excellent candidates for self-assembly smart materials, useful for drug encapsulation and delivery. Their advantage lies also in their biocompatible and biodegradable character

Theoretical studies of energetics and binding isotope effects of binding a triazole-based inhibitor to HIV-1 reverse transcriptase

Understanding of protein-ligand interactions is crucial for rational drug design. Binding isotope effects, BIEs, can provide intimate details of specific interactions between individual atoms of an inhibitor and the binding pocket. We have applied multi-scale QM/MM simulations to evaluate binding energetics of a novel triazole-based non-nucleoside inhibitor of HIV-1 reverse transcriptase and to calculate associated BIEs. The binding sites can be distinguished based on the 18O-BIE.This work has been supported by the grants 2011/02/A ST4/00246 (Maestro) from the Polish National Research Center (NCN) and 0478/IP3/2015/73 (Iuventus Plus) from the Polish Ministry of Science and Higher Education

The Water Project: Is Water Wet?

The goal of this project was to quantify inorganic analytes in water from various sources in the Capital Region1. Specifically, we chose to investigate the differences in inorganic ion concentrations in samples from above- and underground natural water sources. Samples were obtained from Wilsey Creek, Delanson Pond, and the Saratoga Springs, the locations of which are labeled on the map below. Tap water was used to compare these natural water sources to a familiar source. Water sources investigated in this experiment: Saratoga Springs – obtained from downtown spring Wilsey Creek – obtained upstream from road crossing in Burtonville Delanson Pond – obtained from Delanson Farm pond Tap Water – obtained from sink in S&E building at Union College, Schenectadyhttps://digitalworks.union.edu/waterprojectposters/1000/thumbnail.jp

Pharmacological and Structure-Activity Relationship Evaluation of 4-aryl-1-Diphenylacetyl(thio)semicarbazides

This article describes the synthesis of six 4-aryl-(thio)semicarbazides (series a and b) linked with diphenylacetyl moiety along with their pharmacological evaluation on the central nervous system in mice and computational studies, including conformational analysis and electrostatic properties. All thiosemicarbazides (series b) were found to exhibit strong antinociceptive activity in the behavioural model. Among them, compound 1-diphenylacetyl-4-(4-methylphenyl)thiosemicarbazide 1b was found to be the most potentan algesic agent, whose activity is connected with the opioid system. For compounds from series a significant anti-serotonergic effect, especially for compound 1-diphenylacetyl-4- (4-methoxyphenyl)semicarbazide 2b was observed. The computational studies strongly support the obtained results

Ajuste del celóstato del espectroheliógrafo de San Miguel

El tiempo que permanezca quieta la imagen del sol sobre la ranura del espectrógrafo depende de la exactitud de montaje del celóstato. En particular, son cuatro los elementos críticos: 1º que el plano del espejo primario sea paralelo a su eje de rotación (es decir, declinación de su normal Ọ°); 2º que dicho eje esté en el plano meridiano (azimut respecto el plano meridiano O°); 3º que la inclinación del eje de rotación respecto a un plano horizontal sea igual a la latitud del lugar; 4° que el reloj produzca un seguimiento perfecto (una vuelta del espejo en 48 horas del día solar medio).Asociación Argentina de Astronomí