Verfahren zur Sicherung eines SM4-Kryptographieprozesses gegen Seitenkanalangriffe
Anmelder: THALES DIS FRANCE SAS 🇫🇷
Details
- Veröffentlichungs-Nr.
- EP4794248
- Anmeldetag
- 14. Februar 2025
- Veröffentlichung
- 19. August 2026
- Rechtsraum
- EP
- IPC
- H04L9/00, H04L9/06
Abstract
The present invention relates to a method for protecting the execution of SM4 cryptographic process against side-channel attacks by applying 32-bits masks to the inputs of the cryptographic operation and to the round keys. In order to make such a masking compatible with the 8-bit Sbox used by the tau transformation, the present invention generates all masks for all inputs and round keys from a single mask by applying to it a circular permutation shifting the mask to the right or the left by n*8 bits, with n in {0, ...,31} to get masked input values X' and masked round keys RK' such that when computing the value X'<sub>i+1</sub>⊕X'<sub>i+2</sub>⊕X'<sub>i+3</sub>⊕RK'<sub>i</sub> the result will be a 32-bits word composed of four 8-bit chunks all masked by the same mask M<sub>0</sub><sub>xor</sub>. Then the invention replaces the Sbox to be used in SM4 algorithm by a masked Sbox, called SboxM incorporating M<sub>0xor</sub> as input mask and another predefined mask as output mask.
Anmelder
- Firma
- THALES DIS FRANCE SAS
- Land
- 🇫🇷 Frankreich
Französischer Technologiekonzern mit Sitz in Paris, aktiv in Luft- und Raumfahrt, Verteidigungstechnik, Sicherheitstechnologie sowie Bahn- und Kommunikationssystemen für zivile und militärische Anwendungen.
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