INFORMATION DISTRIBUTING METHOD, INFORMATION TRANSMITTER, INFORMATION RECEIVER, INFORMATION TRANSMITTING PROGRAM, INFORMATION RECEIVING PROGRAM, RECORDING MEDIUM STORING INFORMATION TRANSMITTING PROGRAM AND RECORDING MEDIUM STORING INFORMATION RECEIVING PROGRAM

摘要

PROBLEM TO BE SOLVED: To easily provide information distribution while securing secrecy. SOLUTION: Decipher information is prepared and transmitted to a reader A and through the reader A to a reader B by enumerating the pair of a reading range identifier for identifying a reading range to permit reading of a voucher to respective readers A and B and a common key for enciphering this reading range and by enciphering the pair while using the public key of each of readers in an information distributing device 100 of a voucher issuer. In the information distributing device 100 of each of readers A and B, the decipher information received respectively is deciphered by using his/her own secret key and a common key for deciphering the reading range permitted to himself/herself is acquired. In the information distributing device 100 of the voucher issuer, the part designated by the reading range identifier is enciphered by the correspondent common key and transmitted to the reader A and through the reader A to the reader B. In the information distributing device 100 of each of readers A and B, the permitted reading range in the voucher received respectively is deciphered by the common key acquired beforehand.