FRAST: TFHE-Friendly Cipher Based on Random S-Boxes

Abstract: A transciphering framework, also known as hybrid homomorphic encryption, is a practical method of combining a homomorphic encryption (HE) scheme with a symmetric cipher in the client-server model to reduce computational and communication overload on the client side. As a server homomorphically evaluates a symmetric cipher in this framework, new design rationales are required for “HE-friendly” ciphers that take into account the specific properties of the HE schemes. In this paper, we propose a new TFHE-friendly cipher, dubbed FRAST, with a TFHE-friendly round function based on a random S-box to minimize the number of rounds. The round function of FRAST can be efficiently evaluated in TFHE by a new optimization technique, dubbed double blind rotation. Combined with our new WoP-PBS method, the double blind rotation allows computing multiple S-box calls in the round function of FRAST at the cost of a single S-box call. In this way, FRAST enjoys 2.768 (resp. 10.57) times higher throughp.... https://tosc.iacr.org/index.php/ToSC/article/view/11809

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch

References and Relationships

• Bibliographic citation: FRAST: TFHE-Friendly Cipher Based on Random S-Boxes ; volume:2024 ; number:3 ; year:2024 ; IACR transactions on symmetric cryptology ; 2024, Heft 3 (2024)

Contributors, Places and Time

• Creator: Cho, Mingyu ; Chung, Woohyuk ; Ha, Jincheol ; Lee, Jooyoung ; Oh, Eun-Gyeol ; Son, Mincheol

Further information

• DOI: 10.46586/tosc.v2024.i3.1-43
• URN: urn:nbn:de:101:1-2409251858558.885197998543
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 15.08.2025, 7:39 AM CEST