Bartering is defined as the cashless act of trading goods and services in exchange for other goods and services. Bartering has been practiced since the early days of humanity and still plays a crucial role in the global economy. Today, a majority of bartering transactions is carried out via online platforms which allow their users to find potential trade partners in a convenient way. An inherent requirement of these platforms is that a user has to disclose their trading capabilities to the operator and typically also to all other users. As a consequence, private information on the personal preferences of a user is leaked which can undermine their bargaining position.
Within our research project (in cooperation with Professor Wetzel of the Stevens Institute of Technology), we designed decentralized cryptographic protocols that allow multiple users to determine potential trade partners and to barter offered goods and services while keeping their trade capabilities private. More precisely, a user only learns what they get and what they have to give away, but no more information about what their trade partners do in return and no information about the trade capabilities and activities of other users.
Ongoing work deals with bringing theoretical solutions into practice by designing a privacy-preserving bartering system which is capable of handling a large number of users and guaranteing the correctness and fairness of the computed trade while preserving the privacy of its users.
The project was funded by the german research organisation DFG (Deutsche Forschungsgemeinschaft) under the project number ME 3704/4-1.