Projects per year
Abstract
Motivated by new applications such as secure MultiParty
Computation (MPC), Fully Homomorphic Encryption (FHE), and ZeroKnowledge proofs (ZK), the need for symmetric encryption schemes that minimize the number of field multiplications in their natural algorithmic description is apparent. This development has brought forward many dedicated symmetric encryption schemes that minimize the number of multiplications in F2푛 or F푝, with 푝 being prime. These novel schemes have lead to new cryptanalytic insights that have broken many of said schemes. Interestingly, to the best of our knowledge, all of the newly proposed schemes that minimize the number of multiplications use those multiplications exclusively in Sboxes based on a power mapping that is
typically 푥 3 or 푥 −1.
Furthermore, most of those schemes rely on complex and resourceintensive linear layers to achieve a low multiplication count.
In this paper, we present Ciminion, an encryption scheme minimizing the number of field multiplications in large binary or prime fields, while using a very lightweight linear layer. In contrast to other schemes that aim to minimize field multiplications in F2푛 or F푝, Ciminion relies on the Toffoli gate to improve the nonlinear diffusion of the overall design. In addition, we have tailored the primitive for the use in a Farfallelike construction in order to minimize the number of rounds of the used primitive, and
hence, the number of field multiplications as far as possible
Computation (MPC), Fully Homomorphic Encryption (FHE), and ZeroKnowledge proofs (ZK), the need for symmetric encryption schemes that minimize the number of field multiplications in their natural algorithmic description is apparent. This development has brought forward many dedicated symmetric encryption schemes that minimize the number of multiplications in F2푛 or F푝, with 푝 being prime. These novel schemes have lead to new cryptanalytic insights that have broken many of said schemes. Interestingly, to the best of our knowledge, all of the newly proposed schemes that minimize the number of multiplications use those multiplications exclusively in Sboxes based on a power mapping that is
typically 푥 3 or 푥 −1.
Furthermore, most of those schemes rely on complex and resourceintensive linear layers to achieve a low multiplication count.
In this paper, we present Ciminion, an encryption scheme minimizing the number of field multiplications in large binary or prime fields, while using a very lightweight linear layer. In contrast to other schemes that aim to minimize field multiplications in F2푛 or F푝, Ciminion relies on the Toffoli gate to improve the nonlinear diffusion of the overall design. In addition, we have tailored the primitive for the use in a Farfallelike construction in order to minimize the number of rounds of the used primitive, and
hence, the number of field multiplications as far as possible
Original language  English 

Title of host publication  Lecture Notes in Computer Science 
Number of pages  49 
Publication status  In preparation  2021 
Event  Eurocrypt 2021  Zagreb, Croatia Duration: 17 Oct 2021 → 21 Oct 2021 
Conference
Conference  Eurocrypt 2021 

Country  Croatia 
Period  17/10/21 → 21/10/21 
Fingerprint Dive into the research topics of 'Ciminion: Symmetric Encryption Based on ToffoliGates over Large Finite Fields'. Together they form a unique fingerprint.
Projects


FWF  Authenticated Encryption  Advancing in Authenticated Encryption
Dobraunig, C. E.
3/02/20 → 31/08/20
Project: Research project