HASH VALUE GENERATING DEVICE, VERIFICATION DEVICE, HASH VALUE GENERATING METHOD, VERIFICATION METHOD, PROGRAM, AND RECORDING MEDIUM

摘要

<P>PROBLEM TO BE SOLVED: To provide a hash value generating device capable of assuring second preimage resistance and unidirectionality if a compression means has second preimage resistance and unidirectionality. Ž<P>SOLUTION: The hash value generating device comprises: a preprocessing section converting input data X of any length into data Y; a data length adjusting section performing padding to the data Y to output data Z whose data length is a multiple of m-n bits; and a data compression section compressing the data Z by using a compression function to obtain a hash value. The preprocessing section converts the data X into the data Y so that the data Y satisfies the following two conditions: (condition 1) when the data Z is divided into C pieces of m-n bit blocks z[1] to z[C], all blocks z[1] to z[C] include more than μ bits in the data X (μ is a predetermined integer); (condition 2) data X and data Y correspond one-on-one to each other. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž