To generate random numbers having higher safety for a random number generator which is used for ciphering algorithm or the like.
A random number generator 10 is provided with a pseudo-random number generating section 12 which is used to output a plurality of different pseudo-random number sequences, a physical random number generator 14 which generates physical random numbers and a switching section 16 which is used to switch the pseudo-random number sequence of random numbers outputted by the section 12 based on the physical random numbers generated by the generator 14 and the generator 12 sets the output of the section 12 as output random numbers. Since the plurality of different pseudo-random number sequences are switched by the physical random numbers and outputted, predictability of the random numbers is reduced compared with a conventional random number generator which utilizes only pseudo-random numbers. Since the physical random numbers are not directly used as output random numbers , adverse effect on the predictability of output random numbers is relatively made small compared with a conventional device even if some kind of operation is applied to the physical random number generating means from the outside.
TAMAOKI HARUAKI
IKETANI AKIRA
MATHEMATICAL DESIGN RES INST
SANYO SEMICON DEVICE CO LTD
Jun Ishida