| 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; a master secret information generation means 12 of selecting (2m+2) secret information and 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. |
