Searchable Encryption Index Generation for Access Control
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Solution Overview
Problem
Existing searchable encryption technologies face challenges in achieving high-speed search while maintaining access control, with common-key schemes offering high-speed search but limited access control and public-key schemes providing access control but not high-speed search.
Innovation Solution
A system that includes an index generation unit to create encryption keywords for ciphertexts, a key generation unit to generate conversion keys for proxy re-encryption, and a registration unit to transmit these to a server device, enabling high-speed searchable encryption with access control using an index-type scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If common-key scheme searchable encryption is used, then search speed is improved, but access control capability deteriorates
Solution Approach 1:
The patent segments the encryption system into multiple independent key pairs (registration key pairs and search key pairs) instead of using a single common key. Each user receives their own key pairs, allowing simultaneous support for high-speed search operations and fine-grained access control. The registration device holds registration key pairs while search devices hold search key pairs, enabling controlled access without sacrificing search performance.
2Adaptability or versatility
If public-key scheme searchable encryption is used, then access control capability is improved, but search speed deteriorates
Solution Approach 1:
The patent applies different cryptographic qualities to different parts of the system: registration key pairs are used for access control and key management, while search key pairs are optimized for fast search operations. This local differentiation allows each component to operate at optimal performance levels, achieving both fast search and strong access control simultaneously.
3Adaptability or versatility
If tag-type searchable encryption is used, then access control is improved, but search efficiency deteriorates
Solution Approach 1:
The patent dynamically selects between index-type and tag-type encryption methods based on the specific access control requirements and search efficiency needs of different scenarios. The system can adaptively choose the most appropriate encryption type for each data set, optimizing both access control capability and search performance rather than being constrained to a single static approach.
Data Source
AI summary
A registration device (200) generates an encryption keyword by encrypting a keyword with a registration key, generates an index including the encryption keyword and identification information which identifies a corresponding ciphertext, generates a conversion key from the registration key and a search key, and registers a plurality of ciphertexts, the index, and the conversion key in a server device (400). A search device (300) generates a search query by encrypting a keyword, and transmits the search query to the server device (400). The server device (400) generates a re-encryption keyword by re-encrypting the search query with the registered conversion key, searches the registered index with the re-encryption keyword, acquires, from the index, the identification information if the encryption keyword is obtained as a search result, extracts a ciphertext identified by the identification information from the registered plurality of ciphertexts, and transmits the extracted ciphertext to the search device (300).