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, wherein the generating entropy source is different from the saving entropy source, and so the generating of the updated random number state information and the generating of the generating random number state information are performed independently.