Direção de pesquisa : Gilles MULLER

Co-supervisão£o : DAGAND Pierre-Évariste

Usuba, Optimizing Bitslicing Compiler

Bitslicing is a technique commonly used in cryptography to implement high-throughput parallel and constant-time symmetric primitives. However, writing, optimizing and protecting bitsliced implementations by hand are tedious tasks, requiring knowledge of cryptography, CPU microarchitectures and side-channel attacks. The resulting programs tend to be hard to maintain due to their high complexity. To overcome those issues, we propose Usuba, a high-level domain-specific language to write symmetric cryptographic primitives. Usuba allows developers to write high-level specifications of ciphers without worrying about the actual parallelization: an Usuba program is a scalar description of a cipher, from which the Usuba compiler (Usubac) automatically produce vectorized bitsliced code.
When targeting high-end Intel CPUs, the Usubac applies several domain-specific optimizations, such as interleaving and custom instruction-scheduling algorithms. We are thus able to match the throughput of hand-tuned assembly and C implementations of several widely used ciphers.
Furthermore, in order to protect cryptographic implementations on embedded devices against side-channel attacks, we extend our compiler in two ways. First, we integrate into Usubac state-of-the-art techniques in higher order masking to generate implementations that are provably secure against power-analysis attacks. Second, we implement a backend for SKIVA, a custom 32-bit CPU enabling the combination of countermeasures against power-based and timing-based leakage, as well as fault injection.

Publicações 2018-2022

• 2022
  • S. Belaid, D. Mercadier, M. Rivain, A. Taleb : “IronMask: Versatile Verification of Masking Security”, 2022 IEEE Symposium on Security and Privacy (SP), San Francisco, United States, pp. 142-160, (IEEE) (2022)
• 2020
  • D. Mercadier : “Usuba, Optimizing Bitslicing Compiler”, tese, defesas 20/11/2020, direção de pesquisa Muller, Gilles, co-supervisão£o : Dagand, Pierre-Évariste (2020)
  • P. Kiaei, D. Mercadier, P.‑E. Dagand, K. Heydemann, P. Schaumont : “Custom Instruction Support for Modular Defense against Side-channel and Fault Attacks”, International Workshop on Constructive Side-Channel Analysis and Secure Design, COSADE 2020, Lecture Notes in Computer Science, Lugano, Switzerland (2020)
  • S. Belaid, P.‑E. Dagand, D. Mercadier, M. Rivain, R. Wintersdorff : “Tornado: Automatic Generation of Probing-Secure Masked Bitsliced Implementations”, EUROCRYPT, vol. 12107, Lecture Notes in Computer Science, Zagreb / Virtual, Croatia, pp. 311-341, (Springer) (2020)
• 2019
  • D. Mercadier, P.‑E. Dagand : “Usuba: high-throughput and constant-time ciphers, by construction”, PLDI 2019 - 40^th ACM SIGPLAN Conference on Programming Language Design and Implementation, Phoenix, United States, pp. 157-173, (ACM Press) (2019)
• 2018
  • D. Mercadier, P.‑E. Dagand, L. Lacassagne, G. Muller : “Usuba, Optimizing & Trustworthy Bitslicing Compiler”, WPMVP’18 - Workshop on Programming Models for SIMD/Vector Processing, Vienna, Austria, (ACM Press) (2018)