ENCRYPTION SYSTEM, ENCRYPTION PROCESSING METHOD FOR ENCRYPTION SYSTEM, ENCRYPTION DEVICE, ENCRYPTION PROGRAM, DECRYPTION DEVICE, DECRYPTION PROGRAM, SETUP DEVICE, SETUP PROGRAM, KEY GENERATION DEVICE, KEY GENERATION PROGRAM, KEY ASSIGNMENT DEVICE AND KEY ASSIGNMENT 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 C 1 and a cipher value C 3 , and outputs ciphertext data CT including plaintext cipher value C 0 , the cipher value C 1 , and the cipher value C 3 . 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 C 0 included in the ciphertext data CT using the extracted hierarchy identifier, the cipher value C 1 and the cipher value C 3 which are included in the ciphertext data CT, and outputs plaintext data M.