Fair and Decentralized Exchange of Digital Goods

We construct a privacy-preserving, distributed and decentralized marketplace where parties can exchange data for tokens. In this market, buyers and sellers make transactions in a blockchain and interact with a third party, called notary, who has the ability to vouch for the authenticity and integrity of the data. We introduce a protocol for the data-token exchange where neither party gains more information than what it is paying for, and the exchange is fair: either both parties gets the other's item or neither does. No third party involvement is required after setup, and no dispute resolution is needed.Comment: 10 page

Secure Exchange of Digital Goods in a Decentralized Data Marketplace

We are tackling the problem of trading real-world private information using only cryptographic protocols and a public blockchain to guarantee honest transactions. In this project, we consider three types of agents —buyers, sellers and notaries— interacting in a decentralized privacy-preserving data marketplace (dPDM) such as theWibson data marketplace. This framework offers infrastructure and financial incentives for individuals to securely sell personal information while preserving personal privacy. Here we provide an efficient cryptographic primitive for the secure exchange of data in a dPDM, which occurs as an atomic operation wherein the data buyer gets access to the data and the data seller gets paid simultaneously.Sociedad Argentina de Informática e Investigación Operativ

Secure Exchange of Digital Goods in a Decentralized Data Marketplace

We are tackling the problem of trading real-world private information using only cryptographic protocols and a public blockchain to guarantee honest transactions. In this project, we consider three types of agents —buyers, sellers and notaries— interacting in a decentralized privacy-preserving data marketplace (dPDM) such as theWibson data marketplace. This framework offers infrastructure and financial incentives for individuals to securely sell personal information while preserving personal privacy. Here we provide an efficient cryptographic primitive for the secure exchange of data in a dPDM, which occurs as an atomic operation wherein the data buyer gets access to the data and the data seller gets paid simultaneously.Sociedad Argentina de Informática e Investigación Operativ

Secure Exchange of Digital Goods in a Decentralized Data Marketplace

We are tackling the problem of trading real-world private information using only cryptographic protocols and a public blockchain to guarantee honest transactions. In this project, we consider three types of agents —buyers, sellers and notaries— interacting in a decentralized privacy-preserving data marketplace (dPDM) such as theWibson data marketplace. This framework offers infrastructure and financial incentives for individuals to securely sell personal information while preserving personal privacy. Here we provide an efficient cryptographic primitive for the secure exchange of data in a dPDM, which occurs as an atomic operation wherein the data buyer gets access to the data and the data seller gets paid simultaneously.Sociedad Argentina de Informática e Investigación Operativ

Deformation algorithms for polynomial system solving

Esta tesis está dedicada a ciertas tareas computacionales de geometría algebraica en característica cero. Apuntamos a analizar y descubrir la complejidad de problemas definidos por sistemas de ecuaciones polinomiales con una perspectiva de álgebra computacional. La intratabilidad computacional de los enfoques generalistas a los problemas de geometría computacional nos impele a estudiar familias particulares de sistemas de ecuaciones polinomiales en los que la complejidad del peor caso es tratable (y significativamente más baja que la del caso general). Cuando sea posible, proveeremos un método eficiente para encontrar su solución. Como “brújula” para determinar estas familias usamos técnicas de deformación las que, según mostraremos, son sensibles a problemas con buenas propiedades semánticas. Entonces, este trabajo consiste en establecer algunos problemas de eliminación que son tratables y exhibir algoritmos eficientes que los resuelven. Nuestras técnicas de deformación se basan en un procedimiento de levantamiento à la Newton–Hensel que se adapta bien para producir algoritmos que corren en menos pasos cuando las propiedades semánticas referenciadas anteriormente son buenas. Construiremos, entonces, un catálogo de resultados sobre la resolución de sistemas de ecuaciones polinomiales, usando algoritmos de álgebra altamente eficientes, que constituyen mejoras en relación con el estado del arte.This thesis is devoted to computational tasks of basic algebraic geometry in characteristic zero. We aim to analyse and discover the complexity of problems defined by systems of polynomial equations from a computer algebra perspective. The computational intractability of a general approach to geometric elimination problems compels us to study the difficulty of elimination for particular families of polynomial equation systems where worst-case complexity is tractable (and significantly lower than the complexity of tackling the general case). When possible, we provide an efficient solution method. As our “compass” for determining these families, we use deformation techniques which, we will show, are susceptible to problems with well-posed semantic properties. Hence, this work consists in establishing some elimination problems that are tractable, and for these, exhibiting efficient algorithms that tackle them. Our deformation techniques rely on a Newton-Hensel lifting procedure which adapts well in order to obtain algorithms running in fewer steps when certain semantic parameters are “low”. Using highly-efficient algorithms for constructing these geometric elimination procedures, we develop a catalogue of results on polynomial system solving that improve over the prior art.Fil:Waissbein, Ariel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina