Hash value calculation device and the hash value calculation method and hash value calculation program

摘要

PROBLEM TO BE SOLVED: To shorten a length of a message input to a hash function after padding to reduce a calculation amount of the hash function.;SOLUTION: An arithmetic part 104 has n pieces of arithmetic units C₁, ..., C_n. The arithmetic part 104 receives input of a bit string M_i as input to the arithmetic unit C_i (i=1, ..., n), and calculates a hash value of a message M' comprising the bit strings M₁, ..., M_n by use of the arithmetic units C₁, ..., C_n. The bit string M_i has a bit length predetermined in each arithmetic unit C_i. A padding part 102 combines the bit string representing n and a prescribed bit pattern to generate a bit string P, and adds the bit string P to a prescribed position of a message M input by an input part 101 to generate the message M'. Though the bit string S has a predetermined bit length, a bit length of the whole bit string P is set according to a bit length of the message M.;COPYRIGHT: (C)2010,JPO&INPIT