Symmetrically Encrypted Database Search Using Bloom Filters
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Solution Overview
Problem
Current systems for searching symmetrically encrypted databases are inefficient for conjunctive keyword searches, as they typically require downloading and decrypting large volumes of data, and existing solutions do not support searching for conjunctive keywords effectively, compromising data security and efficiency.
Innovation Solution
A system and method utilizing an encrypted index table and a Bloom filter to enable conjunctive keyword searches in a symmetrically encrypted database, where trapdoors are generated only for the shortest clause without a NOT operator, allowing for efficient computation of search tokens and decryption of relevant file identities without revealing the queried keywords to the server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If documents are encrypted using symmetric encryption methods, then data security is improved, but the ability to perform remote search operations on the documents deteriorates
Solution Approach 1:
The patent introduces an intermediary mechanism involving trapdoors and searchable encryption indices that allow the server to search encrypted documents without decrypting them. The trapdoor serves as a mediator between the user's search query and the encrypted document storage, enabling remote search operations while maintaining encryption security.
Solution Approach 2:
The patent replaces the traditional mechanical approach of downloading and decrypting documents locally with a cryptographic mechanism that performs search operations directly on encrypted data at the server level. This substitution eliminates the need for physical data transfer and local decryption while maintaining search functionality.
2Measurement precision
If all documents are downloaded and decrypted locally before searching, then search accuracy is improved, but data transmission time and bandwidth consumption increase
Solution Approach 1:
The patent extracts only the necessary search information (trapdoors for search terms) from the full document set and transmits these compact representations to the server. This extraction approach allows accurate searching without transferring the entire document corpus, significantly reducing transmission time and bandwidth requirements.
Solution Approach 2:
The patent performs preliminary actions by pre-computing and storing encrypted indices and trapdoors at the server level before actual search operations. This preliminary preparation enables rapid search execution without requiring large amounts of data to be transmitted or processed in real-time during the search operation.
3Productivity
If the server is made aware of search queries and results, then search functionality is improved, but data leakage and unauthorized access risks increase
Solution Approach 1:
The patent creates cryptographic copies (trapdoors and encrypted indices) that allow the server to perform search operations without accessing the actual plaintext data. These copies enable search functionality while maintaining the original encrypted data's secrecy, preventing any data leakage to the server or unauthorized parties.
Solution Approach 2:
The patent applies different quality levels of data exposure at different levels of the system. The server receives only encrypted indices and trapdoor information (low quality exposure), while the user retains access to the full encrypted documents (high quality exposure). This local quality differentiation ensures search functionality at the server level without compromising data security.
4Productivity
If existing SSE solutions are used for single keyword search, then search efficiency is improved, but the ability to handle conjunctive keyword searches deteriorates
Solution Approach 1:
The patent extends the SSE mechanism to provide universal search capability that handles both single keyword and conjunctive keyword searches using the same trapdoor and encrypted index framework. This multi-functional approach allows the system to efficiently process complex search queries involving multiple keywords with different operators without requiring separate specialized mechanisms.
Solution Approach 2:
The patent segments the search query into multiple components (individual keywords and logical operators) and processes each component through the encrypted index separately. This segmentation enables the system to handle conjunctive keyword searches by combining results from individual keyword searches while maintaining the efficiency of the underlying SSE mechanism.
Data Source
AI summary
A system and method for searching a symmetrically encrypted database for conjunctive keywords is provided. More particularly, the system and method provides means for searching a symmetrically encrypted database for conjunctive keywords by utilizing an encrypted index table and a Bloom filter. The encrypted index table contains encrypted keywords and their associated index pairs while the Bloom filter contains elements that represent encrypted identity-keyword pairs of the database.