1. A method of generating a random number using a nonvolatile memory, comprising: reading random number state information from the nonvolatile memory when power is supplied; updating a random number state of a random number generator using the random number state information and a saving entropy source, thereby producing updated random number state information; storing the updated random number state information in the nonvolatile memory; updating the random number state of the random number generator using the updated random number state information and a generating entropy source, thereby producing generating random number state information; and producing a random number to be used in an application program using the generating random number state information and the generating entropy source.