| 摘要 |
The object is to provide a decentralized multi-authority functional encryption according to which the security of the whole system does not depend on a single party. Among a plurality of key generation devices 100, arbitrary one key generation device 100 generates gparam, and each key generation device 100 generates an authority public key apk and an authority secret key ask based on gparam. At least some key generation devices 100 among the plurality of key generation devices 100 generate a part of a decryption key usk gid,(t,xt) of the user based on the authority secret key ask. The user forms one decryption by putting together the decryption keys usk gid,(t,xt) generated by at least some of the key generation devices 100, and decrypts a ciphertext cts. |
