International Association for Cryptologic Research

International Association
for Cryptologic Research


Chosen-Ciphertext Secure Dual-Receiver Encryption in the Standard Model Based on Post-Quantum Assumptions

Laurin Benz , Karlsruhe Institute of Technology
Wasilij Beskorovajnov , FZI Forschungszentrum Informatik
Sarai Eilebrecht , FZI Forschungszentrum Informatik
Maximilian Müller , FZI Forschungszentrum Informatik
Jörn Müller-Quade , Karlsruhe Institute of Technology
Roland Gröll , FZI Forschungszentrum Informatik
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Presentation: Slides
Conference: PKC 2024
Abstract: Dual-receiver encryption (DRE) is a special form of public key encryption (PKE) that allows a sender to encrypt a message for two recipients. Without further properties, the difference between DRE and PKE is only syntactical. One such important property is soundness, which requires that no ciphertext can be constructed such that the recipients decrypt to different plaintexts. Many applications rely on this property in order to realize more complex protocols or primitives. In addition many of these applications explicitly avoid the usage of the random oracle, which poses an additional requirement on a DRE construction. We show that all of the IND-CCA2 secure standard model DRE constructions based on post-quantum assumptions fall short of augmenting the constructions with soundness and describe attacks thereon. We then give an overview over all applications of IND-CCA2 secure DRE, group them into generic (i. e., applications using DRE as black-box) and non-generic applications and demonstrate that all generic ones require either soundness or public verifiability. Conclusively, we identify the gap of IND-CCA2 secure DRE constructions with soundness based on post-quantum assumptions in the standard model. In order to fill this gap we provide two direct IND-CCA2 secure DRE constructions based on the standard post-quantum assumptions, Normal Form Learning With Errors (NLWE) and Learning Paritiy with Noise (LPN).
  title={Chosen-Ciphertext Secure Dual-Receiver Encryption in the Standard Model Based on Post-Quantum Assumptions},
  author={Laurin Benz and Wasilij Beskorovajnov and Sarai Eilebrecht and Maximilian Müller and Jörn Müller-Quade and Roland Gröll},