| 摘要 |
PROBLEM TO BE SOLVED: To provide a cryptographic key producing apparatus which ensures uniqueness of primes to be produced in large quantities and does not require a number of storage regions. SOLUTION: On the assumption that (n) is a positive integer of≤1 and fulfilling a condition of 2n=1+m, when preparing a storage region having a length of 2n bits in a storage part, '1' is substituted into a register A of 1 bit and a register B of (m) bits by using an arithmetic operation part and a control part, initialized and saved in the storage part, and the registers A and B are read out of the storage part and connected in the order of A||B||A to obtain M. Then, M is encrypted to obtain C in a CBC mode by using a common key cipher with a processing block length of (n) bits, the M from left side n+1 bits to 3n bits is selected as D and while making the value of B increment by '1', D are produced and linked as many as a number required for a length pLen to obtain a bit stream P'. Then, P' is defined as an integer P" of the bit length pLen, a prime P near this value is obtained and while making the value of B increment by '1', k pieces of P are produced and outputted. COPYRIGHT: (C)2004,JPO
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