Patent ID: 7257224

Claim:
A cryptographical pseudo-random number generation apparatus functioning as a calculation device for word length of w bits, comprising: an input unit inputting natural numbers c, o, and a (c+o≦p where p indicates a prime number, and 2 p −1 also indicates a prime number) and two bit strings (on condition that each bit string includes a bit of 0 and a bit of 1) of a bit length p; an internal status storage unit storing a first bit string of the bit length p input by said input unit; a generator storage unit storing a second bit string of the bit length p input by said input unit; an irreducible polynomial storage unit storing an irreducible polynomial f (t) (=t p +b p-1 t p-1 +b p-2 t p-2 + . . . +b 1 t+b 0 ) of a p-th {0, 1} coefficient depending on a p-bit bit string of {0, 1} coefficient b p-1 b p-2 . . . b 1 b 0 ; and an arithmetic unit, wherein said arithmetic unit computes g s (modf(t)) using a value g of p bits stored in said generator storage unit, a value s of low order c bits of the p bits stored in said internal status storage unit, and a bit string of the p bits stored in said irreducible polynomial storage unit, an arithmetic result of the p bits of the arithmetic unit is stored in said internal status storage unit, low order o bits of the arithmetic result of the p bits are output, and a series of which processes are repeated a times, thereby generating a pseudo-random number.