A Privacy-Preserving Protocol for the Kidney Exchange Problem

Kidney donations from living donors form an attractive alternative to long waiting times on a list for a post-mortem donation. However, even if a living donor for a given patient is found, the donor's kidney might not meet the patient's medical requirements. If several patients are in this position, they may be able to exchange donors in a cyclic fashion. Current algorithmic approaches for determining such exchange cycles neglect the privacy requirements of donors and patients as they require their medical data to be centrally collected and evaluated. In this paper, we present the first distributed privacy-preserving protocol for kidney exchange that ensures the correct computing of the exchange cycles while at the same time protecting the privacy of the patients' sensitive medical data. We prove correctness and security of the new protocol and evaluate its practical performance

Hierarchical and dynamic threshold Paillier cryptosystem without trusted dealer

We propose the first hierarchical and dynamic threshold Paillier cryptosystem without trusted dealer and prove its security in the malicious adversary model. The new cryptosystem is fully distributed, i. e., public and private key generation is performed without a trusted dealer. The private key is shared with a hierarchical and dynamic secret sharing scheme over the integers. In such a scheme not only the amount of shareholders, but also their levels in the hierarchy decide whether or not they can reconstruct the secret and new shareholders can be added or removed without reconstruction of the secret

Исследование люминесцентных характеристик листьев растений

В работе будет исследована возможность и целесообразность применения люминесцентных методов исследования эффективности облучения растений. Результаты работы покажут возможность применения данной методике в исследовательских работах по направлению "Агрофотоника".The possibility and expediency of the application luminescence methods for studying the effectiveness of plant irradiation. The results of the work will show the possibility of using this technique in research works in the direction of "AgroPhotonics"

Privacy-preserving electronic bartering

E-commerce applications like online shopping, e-marketplaces, and e-banking are becoming more and more prevalent in our daily lives. While providing a lot of convenience, these applications generally require the disclosing of sensitive personal data. Typically, it is not transparent for their users what the personal data are used for. A majority of users may be willing to share sensitive personal data on the Internet to some extent when there is a balance between the involved benefits and drawbacks. However, this is certainly not the case if those data (e.g., one's room for negotiation) have the potential to adversely affect e-commerce transactions which, in particular, may occur particularly in the context of online bartering marketplaces. The research goal of this thesis is to advance the privacy-protection of online bartering marketplaces such that users do not have to disclose private data (including their offers/demands as well as the quantities thereof) to anyone in order to find suitable trade partners. Our approach is to design privacy-preserving protocols that can be used as a key component of a bartering system allowing its users to barter their commodities in a privacy-preserving fashion. More precisely, we devise a novel privacy-preserving bartering protocol for the two-party case providing security against active adversaries as well as two novel privacy-preserving bartering protocols for the multi-party case which provide security against passive and active adversaries, respectively. The focus of this thesis is on the much more complicated multi-party case which, compared to the two-party case, requires fundamentally different design approaches as well as the development of novel privacy-preserving building blocks for comparison and selection operations that are of general interest beyond the context of bartering. Using our privacy-preserving multi-party bartering protocols (which are shown to be practical for a limited number of parties) as a key component, we model a bartering system that allows an arbitrary number of parties (arriving at the system over time) to barter their commodities in a privacy-preserving fashion. The implementation and the simulation of our novel privacy-preserving bartering model as well as the comparison to the most prominent conventional bartering models show that the modeled privacy-preserving bartering system is practical

Privacy-Preserving Multi-Party Bartering Secure Against Active Adversaries

A majority of electronic bartering transactions is carried out via online platforms. Typically, these platforms require users to disclose sensitive information about their trade capabilities which might restrict their room for negotiation. It is in this context that we propose a novel decentralized and privacy-preserving bartering protocol for multiple parties that offers the same privacy guarantees as provided by traditional bartering and by cash payments. The proposed protocol is even secure against an active attacker who controls a majority of colluding parties