International Association for Cryptologic Research

International Association
for Cryptologic Research

Transactions on Cryptographic Hardware and Embedded Systems, Volume 2021

Side-Channel Protections for Picnic Signatures


Diego F. Aranha
Department of Computer Science and DIGIT, Aarhus University, Denmark

Sebastian Berndt
University of Lübeck, Germany

Thomas Eisenbarth
University of Lübeck, Germany

Okan Seker
University of Lübeck, Germany

Akira Takahashi
Department of Computer Science and DIGIT, Aarhus University, Denmark

Luca Wilke
University of Lübeck, Germany

Greg Zaverucha
Microsoft Research, USA


Keywords: side-channel attacks, masking, MPC-in-the-head, Picnic signatures


Abstract

We study masking countermeasures for side-channel attacks against signature schemes constructed from the MPC-in-the-head paradigm, specifically when the MPC protocol uses preprocessing. This class of signature schemes includes Picnic, an alternate candidate in the third round of the NIST post-quantum standardization project. The only previously known approach to masking MPC-in-the-head signatures suffers from interoperability issues and increased signature sizes. Further, we present a new attack to demonstrate that known countermeasures are not sufficient when the MPC protocol uses a preprocessing phase, as in Picnic3.

We overcome these challenges by showing how to mask the underlying zero-knowledge proof system due to Katz–Kolesnikov–Wang (CCS 2018) for any masking order, and by formally proving that our approach meets the standard security notions of non-interference for masking countermeasures. As a case study, we apply our masking technique to Picnic. We then implement different masked versions of Picnic signing providing first order protection for the ARM Cortex M4 platform, and quantify the overhead of these different masking approaches. We carefully analyze the side-channel risk of hashing operations, and give optimizations that reduce the CPU cost of protecting hashing in Picnic by a factor of five. The performance penalties of the masking countermeasures ranged from 1.8 to 5.5, depending on the degree of masking applied to hash function invocations.

Publication

Transactions of Cryptographic Hardware and Embedded Systems, Volume 2021, Issue 4

Paper

Artifact

Artifact number
tches/2021/a17

Artifact published
September 10, 2021

README

tar.gz (276 KB)  

View on Github

License
This work is licensed under the MIT License.

Some files in this archive are licensed under a different license. See the contents of this archive for more information.


BibTeX How to cite

Aranha, D. F., Berndt, S., Eisenbarth, T., Seker, O., Takahashi, A., Wilke, L., & Zaverucha, G. (2021). Side-Channel Protections for Picnic Signatures. IACR Transactions on Cryptographic Hardware and Embedded Systems, 2021(4), 239–282. https://doi.org/10.46586/tches.v2021.i4.239-282. Artifact at https://artifacts.iacr.org/tches/2021/a17.