Privacy-Preserving Bartering

• Applicant: Professorin Dr.-Ing. Ulrike Meyer
• Subject Area: Security and Dependability, Operating-, Communication- and Distributed Systems
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 279353706

Bartering is the practice of trading goods or services in exchange for other goods or services, rather than for money. People have likely been bartering for tens of thousands of years, probably even since the advent of humanity. Today, this early form of commerce continues to play a crucial role in the global economy. For example, the U.S. Department of Commerce estimates that 20-25% of world trade is barter and the International Reciprocal Trade Association estimates that in the U.S. alone 470; 000 companies actively barter. In such B2B scenarios, companies typically exchange some of their assets for goods or services of other companies. In addition, bartering once again is of increasing interest to individuals. Typical examples include the bartering of vacation homes, books, or community services. Both B2B bartering as well as bartering between individuals is increasingly facilitated through online platforms such as The National Association of Trade Exchanges or online communities (e.g., SwapRight, or BarterQuest). While these platforms make it easy for businesses and individuals to publish their offers and search for potential trading partners, they suffer from two main shortcomings. First, to date most of these platforms lack automation, i.e., the respective parties have to initiate contact with each other and then negotiate on an individual basis (either face-to-face or possibly online). Second, these platforms disclose crucial information about a potential barter, regardless of whether or not the negotiation will in fact result in an exchange. This in particular pertains to the personal preferences of a party w.r.t. the goods or services as well as the quantity thereof the party intends to barter. The main drawback of the information disclosure is privacy concerns as the disclosure may, for example, reveal sensitive information about the personal interests and needs of an individual or the standing of a business. This proposal outlines a comprehensive research agenda to develop privacy-preserving bartering protocols which allow the determining of a trade in a distributed fashion that (a) does not require a trusted third party, (b) the commodities and the quantities are kept private at all times, (c) all involved parties are satisfied with the trade, i.e., their preferences are properly recognized, thus realizing a notion of unbiasedness, and (d) is secure even in the presence of adversaries. The intellectual merit of the proposed work goes beyond the development of privacy-preserving bartering protocols. In particular, the privacy-preserving building blocks developed to facilitate privacy-preserving bartering are expected to be of interest and use in the greater context of secure multi-party computation. Furthermore, in pursuing a systemic view of bartering, this work is expected to advance the use of secure multi-party computation in practice.

• DFG Programme: Research Grants
• International Connection: USA
• Cooperation Partner: Professorin Dr.-Ing. Susanne Wetzel