ENCRYPTION DEVICE, ENCRYPTION METHOD, INFORMATION PROCESSOR, AND ENCRYPTION SYSTEM

摘要

PROBLEM TO BE SOLVED: To shorten the processing time of re-encryption processing.SOLUTION: An encryption server receives encrypted data encrypted by using the public key of a first user to which auxiliary information calculated by using the combination of the secrete key and public key of the first user and data to be encrypted is attached. Then, the encryption server generates re-encrypted data by re-encrypting the encrypted data by using the auxiliary information attached to the encrypted data, the public key of a second user and encryption information related to the secret key of the first user encrypted with the public key of the second user.