Organizer: Andrea Püchner

Abstract

Oblivious Transfer (OT) is at the heart of secure computation and is a foundation for many applications in cryptography. Over two decades of work have led to extremely efficient protocols for evaluating OT instances in the preprocessing model, through a paradigm called OT extension. A few “base” OT instances generated in an offline phase can be used to perform many OTs in an online phase efficiently, i.e., with very low communication and computational overheads. Recently, a new paradigm of OT with a public-key setup has emerged, which replaces the base OTs with a non-interactive setup: Using only the public key of the other party, two parties can efficiently compute a virtually unbounded number of OT instances on-the-fly. Here, we put forth a novel framework for OT extension with a public-key setup and concretely efficient instantiations.

Publication
Couteau, G., Devadas, L., Devadas, S., Koch, A., Servan-Schreiber, S. (2025). QuietOT: Lightweight Oblivious Transfer with a Public-Key Setup. In: Chung, KM., Sasaki, Y. (eds) Advances in Cryptology – ASIACRYPT 2024. ASIACRYPT 2024. Lecture Notes in Computer Science, vol 15485. Springer, Singapore. https://doi.org/10.1007/978-981-96-0888-1_7.

Speaker Bio

Alexander Koch received his doctoral degree with a dissertation on cryptographic protocols from physical assumptions, in the group of Prof. Dr. Jörn Müller-Quade at KASTEL Security Research Labs, Karlsruhe Institute of Technology (KIT). He is passionate about research on privacy enhancing technologies, such as secure computations on private data and has continued to work on these topics during a PostDoc at KIT and at IRIF, Université Paris Cité.