Predicate Encryption Conversion Rules for Flexible Content Distribution
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Solution Overview
Problem
Existing cryptographic technologies, such as common key and public key systems, face limitations in flexible distribution and decryption of encrypted content, particularly in predicate encryption scenarios where the sender does not necessarily need to know the receiver's information and can freely determine the attributes to embed during encryption.
Innovation Solution
A cryptographic system utilizing predicate encryption with conversion rule information pairs to convert attribute or predicate designation information into attribute or predicate information, allowing flexible operation and distribution of encrypted content through a network of encryption, key generation, and content servers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If predicate encryption is used to allow flexible distribution of encrypted content, then the adaptability and ease of operation are improved, but the device complexity increases due to the need for conversion rule information pairs and multiple apparatuses
Solution Approach 1:
The patent introduces conversion rule information pairs as intermediaries that bridge the gap between simple encryption and flexible decryption. These conversion rules act as mediators that enable the system to handle complex predicate encryption operations without requiring the sender and receiver to directly negotiate or share complex key information, thus improving adaptability while managing system complexity through standardized conversion mechanisms.
Solution Approach 2:
The cryptographic system is segmented into distinct functional components: encryption apparatus, key generation apparatus, and decryption apparatus. Each component has a specific role and processes specific types of information (encryption information, predicate information, attribute information). This segmentation allows the system to achieve high adaptability through specialized components while managing overall complexity by distributing functions across multiple apparatuses rather than concentrating all complexity in a single system.
2Ease of operation
If the sender determines attributes freely without knowing receiver information, then the ease of operation is improved, but the reliability of secure decryption may be compromised
Solution Approach 1:
The receiver performs preliminary actions by generating predicate information and conversion rules in advance, before the encryption occurs. The key generation apparatus pre-generates conversion rule information pairs that will enable future decryption operations. This preliminary preparation ensures that even though the sender operates freely without knowing receiver information, the decryption reliability is maintained because the receiver has already prepared the necessary cryptographic materials that will match the sender's freely chosen attributes.
Solution Approach 2:
The system implements a feedback mechanism through conversion rule information pairs that connect the sender's attribute selection back to the receiver's decryption capability. When the sender encrypts content with freely chosen attributes, the conversion rules embedded in the encryption information provide feedback that enables the receiver to verify whether their predicate information matches the encrypted attributes, thus maintaining decryption security without restricting the sender's operational freedom.
Data Source
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AI summary
A cryptographic communication technology that allows an encrypted content encrypted with predicate encryption to be distributed and that can operate flexibly is provided. A conversion rule information pair is determined in advance, which has attribute conversion rule information prescribing a conversion rule for converting attribute designation information to attribute information used in a predicate encryption algorithm and predicate conversion rule information prescribing a conversion rule for converting predicate designation information to predicate information used in the predicate encryption algorithm. One kind of conversion rule information included in the conversion rule information pair is used to obtain first attribute information or first predicate information from input information. The first attribute information or the first predicate information is used for encryption of content. The encrypted content is stored in a content server. Encryption information is decrypted with a decryption key generated by using second attribute information or second predicate information obtained from user information by using the other kind of conversion rule information.