Patent ID: 8964982
Filing Date: 2015-02-24
Classification: H04L

Abstract:
1. A cryptographic system that uses predicate encryption, comprising at least: one or a plurality of encryption apparatuses; one or a plurality of key generation apparatuses; and one or a plurality of decryption apparatuses; wherein a private key and a public key corresponding to the private key are determined in advance for each of the one or the plurality of key generation apparatuses; one or a plurality of conversion rule information pairs are determined in advance, each pair of which has attribute conversion rule information prescribing a conversion rule for converting attribute designation information that designates an attribute to attribute information used in a predicate encryption algorithm and predicate conversion rule information prescribing a conversion rule for converting predicate designation information that designates a predicate to predicate information used in the predicate encryption algorithm; policy information that identifies one of the attribute conversion rule information and the predicate conversion rule information is determined in advance; each of the one or the plurality of encryption apparatuses comprises circuitry configured to: each of the one or the plurality of key generation apparatuses comprises circuitry configured to: each of the one or the plurality of decryption apparatuses comprises circuitry configured to use the decryption key to apply a decryption process to the encryption information according to the predicate encryption algorithm.