Homomorphic Encryption

Jan Pennekamp, Joseph Leisten, Paul Weiler, Markus Dahlmanns, Marcel Fey, Chrstian Brecher, Sandra Geisler, Klaus Wehrle

MapXchange: Designing a Confidentiality-Preserving Platform for Exchanging Technology Parameter Maps

Proceedings of the 40th ACM/SIGAPP Symposium on Applied Computing (SAC ‘25), March 31-April 4, 2025, Catania, Italy

Technology parameter maps summarize experiences with specific parameters in production processes, e.g., milling, and significantly help in designing new or improving existing production processes. Businesses could greatly benefit from globally exchanging such existing knowledge across organizations to optimize their processes. Unfortunately, confidentiality concerns and the lack of appropriate designs in existing data space frameworks—both in academia and industry—greatly impair respective actions in practice. To address this research gap, we propose MapXchange, our homomorphic encryption-based approach to combine technology parameters from different organizations into technology parameter maps while accounting for the confidentiality needs of involved businesses. Central to our design is that it allows for local modifications (updates) of these maps directly at the exchange platform. Moreover, data consumers can query them, without involving data providers, to eventually improve their setups. By evaluating a real-world use case in the domain of milling, we further underline MapXchange's performance, security, and utility for businesses.

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Jan Pennekamp, Markus Dahlmanns, Frederik Fuhrmann, Timo Heutmann, Alexander Kreppein, Dennis Grunert, Christoph Lange, Robert H. Schmitt, Klaus Wehrle

Offering Two-Way Privacy for Evolved Purchase Inquiries

ACM Transactions on Internet Technology

Dynamic and flexible business relationships are expected to become more important in the future to accommodate specialized change requests or small-batch production. Today, buyers and sellers must disclose sensitive information on products upfront before the actual manufacturing. However, without a trust relation, this situation is precarious for the involved companies as they fear for their competitiveness. Related work overlooks this issue so far: Existing approaches only protect the information of a single party only, hindering dynamic and on-demand business relationships. To account for the corresponding research gap of inadequately privacy-protected information and to deal with companies without an established trust relation, we pursue the direction of innovative privacy-preserving purchase inquiries that seamlessly integrate into today's established supplier management and procurement processes. Utilizing well-established building blocks from private computing, such as private set intersection and homomorphic encryption, we propose two designs with slightly different privacy and performance implications to securely realize purchase inquiries over the Internet. In particular, we allow buyers to consider more potential sellers without sharing sensitive information and relieve sellers of the burden of repeatedly preparing elaborate yet discarded offers. We demonstrate our approaches' scalability using two real-world use cases from the domain of production technology. Overall, we present deployable designs that offer two-way privacy for purchase inquiries and, in turn, fill a gap that currently hinders establishing dynamic and flexible business relationships. In the future, we expect significantly increasing research activity in this overlooked area to address the needs of an evolving production landscape.

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