Settling for limited privacy: how much does it help?

This thesis explores practical and theoretical aspects of several privacy-providing technologies, including tools for anonymous web-browsing, verifiable electronic voting schemes, and private information retrieval from databases. State-of-art privacy-providing schemes are frequently impractical for implementational reasons or for sheer information-theoretical reasons due to the amount of information that needs to be transmitted. We have been researching the question of whether relaxing the requirements on such schemes, in particular settling for imperfect but sufficient in real-world situations privacy, as opposed to perfect privacy, may be helpful in producing more practical or more efficient schemes. This thesis presents three results. The first result is the introduction of caching as a technique for providing anonymous web-browsing at the cost of sacrificing some functionality provided by anonymizing systems that do not use caching. The second result is a coercion-resistant electronic voting scheme with nearly perfect privacy and nearly perfect voter verifiability. The third result consists of some lower bounds and some simple upper bounds on the amount of communication in nearly private information retrieval schemes; our work is the first in-depth exploration of private information schemes with imperfect privacy

Design and prototype of a coercion-resistant, voter verifiable electronic voting system

Abstract — In elections, it is important that voters be able to verify that the tally reflects the sum of the votes that were actually cast, as they were intended to be cast. It is also important that voters not be subject to coercion from adversaries. Currently most proposed voting systems fall short: they either do not provide both properties, or require the voter to be a computer. In this paper, we present a new voting system that uses voter knowledge to allow voter verification by using a receipt that is uninformative for a coercer without access to the voting machine or the contents of the cast ballots. Our system does not assume any trust in the voting machine, but requires a few other assumptions which we believe to be reasonable in the real-world situation. A basic prototype of this system is available on our website. I

Using Caching For Browsing Anonymity

this paper, we propose a caching proxy system for allowing users to retrieve data from the World-Wide Web in a way that would provide recipient unobservability by a third party and sender unobservability by the recipient and thus dispose with intersection attacks, and report on the prototype we built using Googl

Unusual penta-and hexanuclear Ni(II) based silsesquioxane polynuclear complexes.

International audienc

Novel Cage-Like Hexanuclear Nickel(II) Silsesquioxane. Synthesis, Structure, and Catalytic Activity in Oxidations with Peroxides

New hexanuclear nickel(II) silsesquioxane [(PhSiO1.5)12(NiO)6(NaCl)] (1) was synthesized as its dioxane-benzonitrile-water complex (PhSiO1,5)12(NiO)6(NaCl)(C4H8O2)13(PhCN)2(H2O)2 and studied by X-ray and topological analysis. The compound exhibits cylinder-like type of molecular architecture and represents very rare case of polyhedral complexation of metallasilsesquioxane with benzonitrile. Complex 1 exhibited catalytic activity in activation of such small molecules as light alkanes and alcohols. Namely, oxidation of alcohols with tert-butylhydroperoxide and alkanes with meta-chloroperoxybenzoic acid. The oxidation of methylcyclohexane gave rise to the isomeric ketones and unusual distribution of alcohol isomers

Tuning linkage isomerism and magnetic properties of bi- and tri-metallic cage silsesquioxanes by cation and solvent effects

International audienc

High-Nuclearity (Cu₈‑Based) Cage Silsesquioxanes: Synthesis and Structural Study

We herein report a study of Cu­(II)-silsesquioxanes’ self-assembly in the presence of two possible template agents (acetonitrile and acetone). This results in the isolation of unusual high-nuclearity cluster Cu^II₈ cage silsesquioxanes [(Ph₈Si₈O₁₆)₂­Cu₈­(DMF)₈]­[Ph₈Si₈O₁₂]­·2MeCN <b>1</b> and [(Me₈Si₈O₁₆)₂­Cu₈­(Me₂CO)₄]₂­[MeCOO^–]₂­[Na⁺]₂­·2­(H₂O)­·3­(Me₂CO) <b>2</b>. In the case of <b>1</b>, acetonitrile indeed serves as a template being incorporated into the inner void of the prism-like cage of the crystalline product. To the contrary, in the case of complex <b>2</b>, acetone molecules just play the role of external solvates. An inner void of the prism-like cage in <b>2</b> is occupied by sodium acetate groups. The latter, most likely, are produced via the mild oxidation of ethanol during the synthesis of <b>2</b>. Finally, the sodium centers of these acetate groups caused an unprecedented “cage connectivity” (dimerization of two octacopper cage silsesquioxanes in <b>2</b>)

Tridecanuclear Cu^II₁₁Na₂ Cagelike Silsesquioxanes

A series of three unprecedented heterometallic copper­(II) sodium silsesquioxanes were isolated (i) via the unusual rearrangement process during synthesis of coordination polymers or (ii) via the self-assembly reaction using 2,2′-bipyridine. The unique type of these products’ molecular topology consists of an unusual fusion of two sandwich-like components (each including five copper and one sodium sites) via a central copper ion. These compounds correspond to the highest nuclearity among Cu­(II)-based cage silsesquioxanes reported to date