The program, the program content and decoding apparatus, as well as the delivery and content generation device, the program, the program and secret key generation device, the program and specific user and device encryption information generating apparatus

摘要

PROBLEM TO BE SOLVED: To provide a content distribution system for setting the size of a cryptogram to fixed length without depending on the number of users.;SOLUTION: An encrypted information generation server 10 of the content distribution system includes: a basic information generation means 11 of generating m prime numbers and generators, the composite number of the prime numbers, and an element where the generators are composited, and identifying bilinear mapping e from a group G with the composite number and composited element as the order and generator to a group G_T; a master secret information generation means 12 of selecting respective values of 1x₁, ₀, x₁, ₁p₁, ..., 1x_m, ₀, x_m, ₁p_m, 1, , n as secret information, and of generating a master secret key and a public parameter; and a public key generation means 14 of generating a public key based on the public parameter, m prime numbers and the generator, the bilinear mapping e, and the secret information.;COPYRIGHT: (C)2011,JPO&INPIT