METHOD AND DEVICE FOR MAKING ELECTRONIC SIGNATURE BY DIVIDED PARTIAL DECODING AND ELECTRONIC SIGNATURE PREPARATION PROGRAM RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To prepare a reception signature for a plain text being the origin of the code data constituting the proof of reception of the code data from a sender without making the perfect plain text of the code data exist on a receiver's computer when the code data are received. SOLUTION: A divided decode/divided hashing means 1 divides the received code data 21 successively, and decodes the divided code data on a memory in the order of division, and calculates a hash value corresponding to the code data from the decode data of the divided code data, and deletes successively the decode data used for calculating the hash value from on the memory before the next divided code data are decoded. A reception signature generation means 2 prepares the reception signature 23 on the basis of the reception proof information 22 of the hash value calculated by the divided decode/division hashing means 1.