Wildcard Search in Encrypted Text via Preprocessed Keyword Combinations
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Solution Overview
Problem
Cloud-based services lack effective search functionality for encrypted data, as existing searchable encryption algorithms only allow for exact match searching, preventing wildcard searches such as prefix or suffix searches in encrypted text.
Innovation Solution
Implementing a wildcard searchable encryption method in a network intermediary, which preprocesses keywords to generate keyword-wildcard combinations, enabling wildcard searches by appending these combinations to the documents and encrypting them using an exact match searchable encryption algorithm, and storing the search index on the intermediary rather than the cloud service provider.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exact match searchable encryption algorithm is used, then data security is maintained, but wildcard search functionality is lost
Solution Approach 1:
The patent segments the search index into multiple parts: the original encrypted document and appended keyword-wildcard combinations. This allows the system to maintain encrypted storage while enabling wildcard search capabilities through the segmented index structure.
Solution Approach 2:
The patent performs preliminary action by pre-processing keywords to generate keyword-wildcard combinations before encryption. These combinations are appended to the encrypted document, enabling wildcard search functionality to be built into the encrypted index structure in advance.
2Ease of operation
If cloud service provider's search routines are used, then search operations are simplified, but data security control is lost
Solution Approach 1:
The patent introduces an intermediary component - the appended keyword-wildcard combinations in the search index - that enables search operations without requiring the cloud service provider to access or understand the encrypted data. The intermediary structure allows local search processing while maintaining data security.
Solution Approach 2:
The patent implements self-service by enabling the encrypted search index to perform search operations autonomously without cloud service provider intervention. The keyword-wildcard combinations allow the local system to execute wildcard searches directly on encrypted data, eliminating reliance on external search routines.
3Adaptability or versatility
If wildcard search is enabled in encrypted text, then search versatility is improved, but encryption algorithm complexity increases
Solution Approach 1:
The patent reduces complexity by segmenting the wildcard search functionality into separate keyword-wildcard combination entries in the search index, rather than implementing complex wildcard matching logic within the encryption algorithm itself. Each combination is treated as an independent searchable unit.
Solution Approach 2:
The patent performs preliminary processing to generate all necessary keyword-wildcard combinations before encryption, converting the complex wildcard search problem into a series of simpler exact match searches on pre-generated combinations.
Data Source
AI summary
A wildcard searchable encryption method enables wildcard search of encrypted text in a cloud-stored encrypted document. In some embodiments, the wildcard searchable encryption method is implemented in a network intermediary, such as a proxy server. The network intermediary encrypts documents on behalf of a user or an enterprise destined to be stored on a cloud service provider. The wildcard searchable encryption method performs keyword pre-processing of the document to be encrypted to generate a set of keyword-wildcard combinations in plaintext for some or all of the keywords in the document. The processed document is encrypted using an exact match searchable encryption algorithm. As a result of the encryption process, a search index is generated to include the keyword-wildcard combinations. As thus configured, the wildcard searchable encryption method enables wildcard search of the encrypted text, such as searches for prefixes or suffixes of the keywords.