Confidentiality-Preserving Rank-Ordered Search Using Encrypted Indices
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Solution Overview
Problem
Existing information retrieval systems face challenges in securely and efficiently searching large-scale encrypted databases, particularly in protecting data confidentiality while enabling accurate and efficient search capabilities, especially in scenarios involving unauthorized access and insider threats.
Innovation Solution
A confidentiality-preserving rank-ordered search system that utilizes cryptographic encryption and hashing primitives to securely build and query term frequency indices, allowing for secure relevance scoring and retrieval of documents without exposing sensitive information, even when accessed remotely through a data center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data collections are encrypted to protect confidentiality, then security against unauthorized access is improved, but search capability and retrieval efficiency deteriorate
Solution Approach 1:
The patent segments the search process into multiple stages: encrypted index building, encrypted query processing, and selective decryption. The index is divided into encrypted term frequency tables and encrypted inverted indexes, allowing search operations to be performed on encrypted data structures without exposing the actual document contents, thus maintaining both security and search capability
Solution Approach 2:
The patent introduces encrypted index structures as intermediaries between the encrypted document collection and the search query. These encrypted indexes act as a mediator that enables efficient search operations on encrypted data without requiring decryption of the actual document contents, resolving the contradiction between security and search efficiency
2Measurement precision
If all encrypted data is transferred to user's side for decryption and search, then search accuracy is improved, but bandwidth consumption and transfer time increase
Solution Approach 1:
The patent extracts only the necessary index structures (encrypted term frequency tables and encrypted inverted indexes) from the full document collection and transfers them to the user's side. This extraction approach enables accurate search operations without transferring the entire encrypted document collection, significantly reducing bandwidth consumption while maintaining search accuracy
Solution Approach 2:
The patent performs preliminary indexing of the document collection into encrypted index structures before the search operation. This preliminary action creates compact encrypted representations of the document collection that can be efficiently transferred and queried, avoiding the need to transfer and process the full document collection during each search operation
3Reliability
If conventional encryption methods are used, then data confidentiality is improved, but computational complexity for search operations increases
Solution Approach 1:
The patent changes the cryptographic parameters and operations used in conventional encryption methods. It employs specific encryption schemes for building encrypted indexes and performing search operations that are optimized for this purpose, reducing the computational complexity compared to generic encryption methods while maintaining data confidentiality
Data Source
AI summary
A confidentiality preserving system and method for performing a rank-ordered search and retrieval of contents of a data collection. The system includes at least one computer system including a search and retrieval algorithm using term frequency and/or similar features for rank-ordering selective contents of the data collection, and enabling secure retrieval of the selective contents based on the rank-order. The search and retrieval algorithm includes a baseline algorithm, a partially server oriented algorithm, and/or a fully server oriented algorithm. The partially and/or fully server oriented algorithms use homomorphic and/or order preserving encryption for enabling search capability from a user other than an owner of the contents of the data collection. The confidentiality preserving method includes using term frequency for rank-ordering selective contents of the data collection, and retrieving the selective contents based on the rank-order.