MULTIPLE ENCRYPTION KEY DELIVERY SYSTEM, MULTIPLE ENCRYPTION KEY DELIVERY METHOD, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To allow the size of a cipher text to be constant even after encryption with one public key, and to assure safety even if a public key of a user of malicious intent is mixed with.;SOLUTION: A transmission device includes a key pair selection part for selecting m pairs of public key/secret key, and an encryption part. The encryption part includes a factor calculation means for calculating factors c, t, and τ, a key K generation means for calculating a key K, and a cipher text generating means which generates a cipher text C from c, τ, and element ρ of a set V. A reception device includes a partial decryption part, a key K connection part for generating a key K by connecting a partial key, and a decryption part. The partial decryption part includes a first public key inspection means for inspecting m public keys, a first factor inspection means for inspecting factors c and τ, and a partial key calculation means for calculating a partial key. The decryption part includes a second public key inspection means for inspecting m public keys, and a second factor inspection means for inspecting factors c and τ.;COPYRIGHT: (C)2013,JPO&INPIT