Cryptography processor for use with smart card for encrypting e.g. personal data, has processor unit arranged to compute result of exponentiation based on random base value, and random number generator arranged to produce random number

摘要

The processor (100) has a random number generator (110) arranged to produce a random number (R). A processor unit (120) computes in order to sum a base value with multiples of module value in order obtain a random base value depending on multiples of the module value of the random number. The processor unit is arranged to compute the result of the exponentiation based on the random base value. The random number generator is arranged to produce the random number with pre-defined bit length. Independent claims are also included for the following: (1) a method for computing a result of a exponentiation of a base value with an exponent module of a module value (2) a computer program comprising a set of instructions for computing a result of a exponentiation of a base value with an exponent module of a module value.