An Algebraic Framework for Silent Preprocessing with Trustless Setup and Active Security

Recently, number-theoretic assumptions including DDH, DCR and QR have been used to build powerful tools for secure computation, in the form of homomorphic secret-sharing (HSS), which leads to secure two-party computation protocols with succinct communication, and pseudorandom correlation functions (PCFs), which allow non-interactive generation of a large quantity of correlated randomness. In this work, we present a group-theoretic framework for these classes of constructions, which unifies their approach to computing distributed discrete logarithms in various groups. We cast existing constructions in our framework, and also present new constructions, including one based on class groups of imaginary quadratic fields. This leads to the first construction of two-party homomorphic secret sharing for branching programs from class group assumptions. Using our framework, we also obtain pseudorandom correlation functions for generating oblivious transfer and vector-OLE correlations from number-theoretic assumptions. These have a trustless, public-key setup when instantiating our framework using class groups. Previously, such constructions either needed a trusted setup in the form of an RSA modulus with unknown factorisation, or relied on multi-key fully homomorphic encryption from the learning with errors assumption. We also show how to upgrade our constructions to achieve active security using appropriate zero-knowledge proofs. In the random oracle model, this leads to a one-round, actively secure protocol for setting up the PCF, as well as a 3-round, actively secure HSS-based protocol for secure two-party computation of branching programs with succinct communication

Bringing Foundations and Governments Closer - Evidence from Mexico

The recommendations formulated in the study provide the basis for close and effective cooperation between Mexican foundations and government agencies, including the Mexican Agency for International Development Co-operation, Agencia Mexicana de Cooperación Internacional para el Desarrollo (AMEXCID). The study expands the spectrum of key development partners for a co-operation agency of the South. Similarly, it has been recognised that not only governments, but all actors, including foundations, must co-operate and assume their respective responsibilities in order to achieve the SDGs

Sanitation as a Business: Unclogging the Blockages

The first Unclogging the Blockages conference took place in Kampala, Uganda in February 2014 with the aim of putting on the table some of the major challenges facing the scale up of sustainable sanitation as well as collaborating towards innovaive soluions. This report summarizes the discussions and takeaway messages from the conference, including concrete action plans developed around a number of thematic areas. [KEY FINDINGS]Market based approaches are key to addressing some of the main barriers for scaling sustainable sanitation solutions. Participants came away with a much richer understanding of the principles and key tenets of sanitation as a business. A push for greater integration in sanitation programming between the housing, energy, business, health, and education sectors will allow for sustainable city and district-wide sanitation services.Unlocking finance for businesses and households and embedding monitoring within all work is critical. One interesting outcome of the group work was a suggestion to form a Global Sanitation Financing Alliance.Supporting sanitation businesses to be successful in the realities of the market requires on-the-ground, real time, market-focused technology development and R&D. A variety of these technologies were on display at the meeting

Preserving Both Privacy and Utility in Network Trace Anonymization

As network security monitoring grows more sophisticated, there is an increasing need for outsourcing such tasks to third-party analysts. However, organizations are usually reluctant to share their network traces due to privacy concerns over sensitive information, e.g., network and system configuration, which may potentially be exploited for attacks. In cases where data owners are convinced to share their network traces, the data are typically subjected to certain anonymization techniques, e.g., CryptoPAn, which replaces real IP addresses with prefix-preserving pseudonyms. However, most such techniques either are vulnerable to adversaries with prior knowledge about some network flows in the traces, or require heavy data sanitization or perturbation, both of which may result in a significant loss of data utility. In this paper, we aim to preserve both privacy and utility through shifting the trade-off from between privacy and utility to between privacy and computational cost. The key idea is for the analysts to generate and analyze multiple anonymized views of the original network traces; those views are designed to be sufficiently indistinguishable even to adversaries armed with prior knowledge, which preserves the privacy, whereas one of the views will yield true analysis results privately retrieved by the data owner, which preserves the utility. We present the general approach and instantiate it based on CryptoPAn. We formally analyze the privacy of our solution and experimentally evaluate it using real network traces provided by a major ISP. The results show that our approach can significantly reduce the level of information leakage (e.g., less than 1\% of the information leaked by CryptoPAn) with comparable utility

Program Learning Event on Violence against Children in and around Schools in East Africa

Sponsored by the Elevate Children Funders Group (ECFG), a three-day Program Learning Event (PLE) on Violence against Children in and around Schools (VACiS) held in Kampala, Uganda from 14-16 July 2015, attracted 77 practitioners, donors, advocates, researchers and government representatives in the field of violence against children from Uganda, Tanzania, Kenya, South Africa, Germany, the United Kingdom and United States of America. The theme of the event was developing a common learning agenda on preventing and responding to VACiS

"Challenge Current Practice and Assumptions! Make waves!!” : What Works Scotland Collaborative Learning Event 23 & 24 February 2016 Queens Hotel, Perth

No abstract available