CARRY-BASED DIFFERENTIAL POWER ANALYSIS AND ITS APPLICATION TO TESTING FOR VULNERABILITY OF SHA-2 AND HMAC-SHA-2 TO SIDE CHANNEL ATTACK

In a general aspect, a method for testing vulnerability of a cryptographic function (CF) to a side-channel attack includes providing a plurality of input values to the function, where the CF, for each input value calculates a sum of the input value and a first value of the CF, and replaces a second value of the CF with the sum. The method further includes measuring a set of samples including a respective side-channel leakage sample for each input value. The method also includes iteratively performing a series of operations including splitting the set of samples into a plurality of subsets based on the input values, calculating a respective value for each subset based on samples of the subset, and comparing the respective values for different subsets to discover respective bit values of the first value and the second value from their least significant bits to most significant bits.