correction steps required in conventional division when quotient digit estimates are inaccurate, it is mostly free of the conditional branches which are the primary targets of timing and power side-channel attacks; the sequence of instructions executed is independent of the input operand values. The only exception is the final conditional subtraction of the modulus, but it is easily modified (to always subtract something, either the modulus or zero) to make it resistant. It is of course necessary to ensure that the exponentiation algorithm built around the multiplication primitive is also resistant. See also Barrett reduction References External links Computer arithmetic Cryptographic algorithms Modular arithmetic