Countermeasure method against side channel analysis for cryptographic algorithms using boolean operations and arithmetic operations

摘要

The present invention relates to a countermeasure method against side channel analysis for cryptographic algorithm using Boolean operations and arithmetic operation. To protect a cryptographic algorithm combining Boolean and arithmetic instructions against first order side channel analysis, it is necessary to perform conversions between Boolean masking and arithmetic masking. The present invention proposes a new conversion method from arithmetic masking to Boolean masking, using only one pre-computed table T. Said table T being configured so that to convert from arithmetic to Boolean masking k-bit nibble by k-bit nibble for integers having a size greater than k bits while adding a masked carry from the modular addition to the nibble.