SYSTEM FOR PROVING THAT PLAIN SENTENCE OF CIPHERED SENTENCE IS PROVIDED WITHIN SECTION, PREPARATION METHOD FOR PROVING SENTENCE AND VERIFICATION METHOD BY THE PROVING SENTENCE

摘要

PROBLEM TO BE SOLVED: To prove that a committed number is provided in a determined section while hiding the committed number from a verifier in the case that the committed number is provided within the determined section by obtaining the committed number from a supplied commitment for the commitment. SOLUTION: In a proving sentence preparation device for preparing a proving sentence for proving that a numerical value which is the plain sentence of a probability ciphered sentence is provided within a specified range, a deciphering part for deciphering the probability ciphered sentence and acquiring the value of the plain sentence and the value of a random number used for ciphering the plain sentence to the probability ciphered sentence is provided and the proving sentence is prepared by using the value of the plain sentence and the value of the random number acquired by the ciphering part.