ENCRYPTION SYSTEM, ENCRYPTION PROCESSING METHOD OF ENCRYPTION SYSTEM, ENCRYPTION DEVICE, ENCRYPTION PROGRAM, DECRYPTION DEVICE, DECRYPTION PROGRAM, SETUP DEVICE, SETUP PROGRAM, KEY GENERATION DEVICE, KEY GENERATION PROGRAM, KEY DELEGATION DEVICE, AND KEY DELEGATION PROGRAM

摘要

In a wildcard-applicable anonymous hierarchical identity-based encryption system, it is aimed to make the number of pairing operations a fixed number. A user identifier ID and a pattern P are used. The user identifier ID includes k number of hierarchy identifiers. The pattern P includes either of a hierarchy identifier, a wildcard value and a blank value for each hierarchy. An encryption device 400 extracts a key value H corresponding to a hierarchy of the wildcard value and a key value H corresponding to a hierarchy of a pattern value from a public key PK, calculates a cipher value C1 and a cipher value C3, and outputs ciphertext data CT including plaintext cipher value C0, the cipher value C1, and the cipher value C3. A decryption device 300 extracts the hierarchy identifier of the hierarchy corresponding to the wildcard value from the user identifier ID, decrypts the plaintext cipher value C0 included in the ciphertext data CT using the extracted hierarchy identifier, the cipher value C1 and the cipher value C3 which are included in the ciphertext data CT, and outputs plaintext data M.