Countermeasure method in an electronic component for an encryption algorithm with secret key.

摘要

Countermeasure method that uses against attacks type DPA an arithmetic representation and a Boolean representation consisting in preventing the previous recording of the current consumption generated by bit manipulations by bits allowing to pass efficiently from said boolean data representation, such representation is called D xor R, or xor designating the operation type XOR, to said arithmetic representation of data, said representation is called D + R, said method using a data x to be protected, the protected data is called x ' 'with x = x' xor r, the integer r is a random integer, said process allows to obtain a value a as x = a + r, said method being characterized in that includes the following two steps: 1) 1 For all and possible integer values, generate a table T containing the values: T (y) = (y xor r) -r 1) 2 Put into an integer value a T (x ').