Encryption statistical processing system, decryption system, key generation apparatus, proxy apparatus, encryption statistical data generation apparatus, encryption statistical processing method, and encryption statistical processing program

摘要

[Problem] To provide a technique for performing statistical processing of encrypted data encrypted using different public keys while the data remains encrypted. [Solution] Provided are: a key-retention means for retaining homomorphically encrypted public keys and private keys; a full-public-key acquisition means for acquiring a full public key for generating encrypted information that can be decrypted in a distributed manner; a proxy-key generation means for generating a proxy key for converting encrypted data encrypted using a public key into reencrypted data that can be decrypted in a distributed manner; a reencryption means for converting encrypted data encrypted using a public key into reencrypted data using the proxy key; and an encrypted statistical data generation means for generating encrypted statistical data that can be decrypted into statistical information related to the original data, by performing a calculation using homomorphism on at least one of the reencrypted data items converted using the reencryption means from at least one of the encrypted data items encrypted using at least one of the public keys.