Response-Hiding Searchable Encryption via ORAM
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Solution Overview
Problem
Current searchable encryption methods are either computationally expensive, making them impractical for large datasets, or they compromise security and privacy to improve efficiency, and they are also vulnerable to attacks that reveal query responses.
Innovation Solution
The implementation of a response-hiding searchable encryption system using oblivious random access memory (ORAM) in a blackbox manner, which provides constant efficiency in ORAM operations and minimizes leakage to untrusted servers, while maintaining privacy and security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fully homomorphic encryption is used for searchable encryption, then security and privacy are maintained, but computational cost becomes extremely expensive and prohibitive for large document sets
Solution Approach 1:
The patent segments the searchable encryption system into multiple components: symmetric encryption for document content, asymmetric encryption for keyword indexing, and ORAM for access pattern hiding. This segmentation allows each component to be optimized independently, achieving both security and efficiency that would be impossible with a single approach like fully homomorphic encryption.
Solution Approach 2:
The patent introduces an intermediary indexing structure that stores encrypted keyword-document mappings. This intermediary layer allows the server to perform efficient searches on encrypted data without requiring computationally expensive fully homomorphic encryption operations, thus resolving the contradiction between security and computational efficiency.
2Productivity
If traditional searchable encryption methods are used to improve efficiency, then computational cost is reduced, but security and privacy are sacrificed and the system becomes vulnerable to attacks that reveal query responses
Solution Approach 1:
The ORAM protocol acts as an intermediary between the client and server interactions, masking the true access patterns. This allows efficient search operations while preventing the server from inferring information about query responses, thus maintaining both efficiency and security/privacy simultaneously.
Solution Approach 2:
The patent transitions from direct encrypted search operations to a two-phase approach: first establishing an ORAM-based access pattern, then performing the actual search. This phase transition allows the system to achieve both efficiency and security by separating the access control mechanism from the search execution.
3Ease of operation
If searchable encryption systems reveal access patterns to the server, then search functionality is simplified, but the system becomes vulnerable to attacks that can infer document contents and query responses
Solution Approach 1:
The ORAM protocol serves as an intermediary that masks access patterns while maintaining search functionality. It allows the server to process search requests without being able to infer which documents are being accessed, thus preserving both ease of operation and security against inference attacks.
Solution Approach 2:
The ORAM creates an inert environment for data access by randomizing and masking all access patterns. This inert atmosphere prevents the server from gathering useful information about query responses and document contents, eliminating the vulnerability while maintaining search functionality.
Data Source
AI summary
A method for providing response-hiding searchable encryption includes receiving a search query for a keyword from a user device associated with a user. The keyword appears in one or more encrypted documents within a corpus of encrypted documents stored on an untrusted storage device. The method also includes accessing a document oblivious key-value storage (OKVS) to obtain a list of document identifiers associated with the keyword. Each document identifier in the list of document identifiers associated with a respective keyword identifier is concatenated with the keyword and uniquely identifies a respective one of the one or more encrypted documents that the keyword appears in. The method also includes returning the list of document identifiers obtained from the document OKVS to the user device.