Wildcard Search Indexing for Encrypted Data

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Solution Overview

Problem

Conventional encryption schemes render data inaccessible for search operations on the server side, leading to high communication overhead, resource constraints, and computational burdens due to the need for decryption and storage of large encrypted datasets.

Innovation Solution

A method for performing wildcard keyword searches on encrypted data using a data encryption key (DEK) and index encryption key (IEK) to generate and shuffle primes, creating an index that allows for efficient querying and retrieval of encrypted data without decryption, enabling lightweight key management between client and server.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data are encrypted by conventional encryption schemes, then security is improved, but search capability deteriorates

Engineering Contradiction:

ImprovesecurityVSAvoidsearch capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces an intermediary indexing mechanism that operates on encrypted data without requiring decryption. The system creates searchable indexes from encrypted keywords using cryptographic transformations, allowing the server to perform search operations directly on encrypted data while maintaining security. This intermediary layer bridges the gap between encrypted storage and search functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the search process into client-side and server-side operations. The client generates search tokens from encrypted keywords, while the server performs matching operations on these tokens against encrypted data indexes. This segmentation allows search capability to be restored without compromising the encrypted state of the data.

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If data are downloaded and decrypted locally for search, then search capability is improved, but communication overhead increases

Engineering Contradiction:

Improvesearch capabilityVSAvoidcommunication overhead

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent performs preliminary actions by pre-computing and storing encrypted indexes on the server side. When a search is needed, the client only needs to send a compact search token rather than downloading entire datasets. This preliminary indexing eliminates the need for large-scale data transfer while maintaining search functionality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts only the essential search token from the client side and leaves the bulk of encrypted data on the server. This extraction approach allows search operations to be performed without transferring large amounts of data, significantly reducing communication overhead while preserving search capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Ease of operation

If all ciphertexts are downloaded and stored locally, then search capability is improved, but storage cost increases

Engineering Contradiction:

Improvesearch capabilityVSAvoidstorage cost

Core Design Contradiction:

Ease of operationVSQuantity of substance

Solution Approach 1:

The patent extracts and stores only the compressed encrypted indexes on the server rather than the full encrypted datasets. The client stores minimal local state (encrypted keywords and search tokens). This extraction strategy enables search functionality while dramatically reducing the quantity of data that needs to be stored and transferred.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent creates lightweight cryptographic copies (search tokens and indexes) that represent the essential searchability of the encrypted data without requiring storage of the full datasets. These cryptographic copies enable search operations with minimal storage requirements on both client and server sides.

Inventive Principle:

Principle #26Copying

4Ease of operation

If all ciphertexts are decrypted locally, then search capability is improved, but computational burden increases

Engineering Contradiction:

Improvesearch capabilityVSAvoidcomputational burden

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent performs preliminary cryptographic transformations to create searchable indexes before data is stored on the server. This preliminary action eliminates the need for computationally intensive decryption operations during search, as all cryptographic processing is completed in advance during index creation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent inverts the conventional approach by performing cryptographic operations on the server side during index creation rather than requiring decryption on the client side during search. This inversion shifts the computational burden from the resource-constrained client to the more powerful server, enabling efficient searching without local decryption.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10984052B2System and method for multiple-character wildcard search over encrypted data

Publication Date: 2021.04.20 BEIJING JINGDONG SHANGKE INFORMATION TECH CO LTD

AI summary

A method and system for searching encrypted data using wildcard keywords. The method includes: obtaining, by a first computing device, a keyword for data to be encrypted, where the keyword has a fixed length; generating a sequence of primes; determining corresponding one prime from the sequence of primes for each character of the keyword; and defining a product of the corresponding primes of the characters of the keyword as index of the encrypted data, where the index can be searched using a wildcard search keyword.