Client-Server Encrypted Data Storage for Range Queries

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Solution Overview

Problem

Existing cloud storage systems face challenges in securely storing security-sensitive data, such as numerical and textual data, while enabling range queries, as the data becomes accessible to cloud providers and may violate legal regulations.

Innovation Solution

A client device and data storage server system that uses message authentication codes (MAC) to encrypt and decrypt data, allowing range queries on encrypted data without revealing the plaintext, by splitting binary representations into significant and least significant bits, and using these bits to index and retrieve data securely.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is stored in plaintext in remote data storage servers, then data can be easily queried, but security sensitive data becomes accessible to cloud storage providers which may violate legal regulations

Engineering Contradiction:
Improvedata securityVSAvoiddata query capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent segments data into two parts: significant bits (stored encrypted in the database) and least significant bits (stored in an encrypted index structure). This segmentation allows the system to maintain security while enabling range queries, as the index structure can be searched without exposing the full plaintext data to the cloud provider.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary index structure that acts as a mediator between the encrypted data and query operations. The index contains encrypted least significant bits and MACs that enable range queries without requiring the cloud provider to access or decrypt the actual sensitive data, thus maintaining both security and query functionality.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If data is encrypted in remote data storage servers, then data security is improved, but range queries cannot be performed on the encrypted data

Engineering Contradiction:
Improvedata securityVSAvoidrange query efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

By dividing data into significant bits (for security) and least significant bits (for indexing), the patent enables range queries on encrypted data. The index structure stores encrypted least significant bits that can be efficiently searched, while the significant bits remain securely encrypted in the main database.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of encryption from full-data encryption to selective encryption of only the significant bits portion. This parameter change allows the least significant bits to be stored in an accessible index structure, enabling range queries while maintaining security for the critical portions of the data.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If only encrypted data is stored in cloud, then privacy and legal compliance are maintained, but the cloud provider cannot perform queries on the data

Engineering Contradiction:
Improveprivacy complianceVSAvoiddata accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent segments data storage into two locations with different security levels: encrypted significant bits in the cloud database and encrypted least significant bits in an index structure. This allows the cloud provider to access and search the index for range queries while the sensitive significant bits remain securely encrypted and inaccessible to the cloud provider.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The index structure serves as an intermediary that enables query operations without exposing sensitive data to the cloud provider. The index contains encrypted least significant bits and MACs that allow the cloud provider to perform range queries and return results to the client, who then decrypts and processes the final data.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4154147B1Data storage server and client devices for securely storing data
Publication Date: 2025.09.24 HUAWEI TECH CO LTD
  • EP4154147B1 patent drawingFigure 1
  • EP4154147B1 patent drawingFigure 2
  • EP4154147B1 patent drawingFigure 3

AI summary

The disclosure relates to a client device (110) for storing data (125a) comprising data elements, for instance numerical values in a database (125) of a server (120). The client device is configured to generate with a MAC key (115b) a first MAC of a first portion of a binary representation of each data element. The first portion comprises the most significant bits of the binary representation of the data element, wherein the binary representation further comprises a complementary remainder portion defined by the remaining least significant bits. Moreover, the client device is configured to store the remainder portion in encrypted form in a data bucket in the database, wherein the data bucket is identified by the first MAC. Advantageously, the client device and the server allow storing security sensitive data in encrypted form in the database, while enabling range queries of the data.