Method for secure distribution of data

(57) An electronic signature is given to the data to which summary invention should be transmitted about data and/or the secret distribution method of a program. The unit which receives data and/or a program inspects an electronic signature by performing the modular multiplication which needs multiplication and division. If invention is followed, a signature will be inspected by performing the modular multiplication by Montgomery to which the auxiliary multiplication by the factor and even number index to which the unit which receives data and/or a program uses 2 as a bottom is performed.