Homomorphic Bill Record Filtering for Private Amount Statistics

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Solution Overview

Problem

Existing privacy protection methods for personal bill records, such as symmetric encryption, require decryption for computations, weakening privacy protection, and lack support for direct computations on ciphertext, especially in scenarios like personal bill filtering and amount statistics.

Innovation Solution

A privacy-preserving method using homomorphic encryption, specifically the Paillier encryption system, to encrypt and process personal bill data, allowing filtering and statistics on ciphertext without decryption, supporting AND/OR connections for filtering conditions and enabling encrypted amount statistics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If symmetric encryption algorithms (AES) are used to encrypt personal bill data, then encryption efficiency and maturity are improved, but the ability to perform computations on ciphertext is lost, requiring decryption first which weakens privacy protection

Engineering Contradiction:
Improveencryption maturityVSAvoidprivacy protection effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces symmetric encryption (AES) with homomorphic encryption (Paillier scheme) to substitute the mechanical decryption-computation-encryption process with a direct ciphertext-computation process. This substitution enables computations on encrypted data without decryption, resolving the contradiction between encryption maturity and privacy protection effectiveness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the encryption parameter from symmetric key-based AES to asymmetric Paillier homomorphic encryption. This parameter change enables the ciphertext to retain computational properties while maintaining security, allowing both efficient encryption and direct computation on encrypted data without compromising privacy.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If homomorphic encryption is used to perform computations on ciphertext, then privacy protection is improved, but the complexity of cryptographic operations and algorithm design increases

Engineering Contradiction:
Improveprivacy protectionVSAvoidcryptographic algorithm complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the complex homomorphic encryption process into manageable components: key generation (generate public/private key pairs), encryption (convert plaintext to ciphertext), homomorphic operations (perform computations on ciphertext), and decryption (convert ciphertext to plaintext). This segmentation reduces the complexity burden on any single operation while maintaining overall privacy protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a trusted third party as an intermediary that handles complex cryptographic operations. This intermediary manages the key pairs and facilitates homomorphic computations, reducing the complexity burden on the user and simplifying the overall system architecture while maintaining strong privacy protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If data is encrypted before upload to server, then privacy protection is improved, but the ability to perform filtering and statistics operations is lost without decryption

Engineering Contradiction:
Improvedata securityVSAvoiddata processing capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent makes the encrypted data structure universal by designing it to support multiple operations: filtering by amount range, time range, and keyword search, as well as statistical operations like summing amounts. The homomorphic encryption scheme enables all these operations to be performed directly on ciphertext, providing multi-functionality without requiring decryption and thus maintaining both security and versatility.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a computational copy of the data in encrypted form. The homomorphic encryption produces a ciphertext that preserves the structural and computational properties of the original plaintext, allowing filtering and statistics operations to be performed on this encrypted copy without accessing the actual data values, thus maintaining privacy while enabling versatile processing.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS20260073075A1Privacy-preserving method for personal bill record filtering and amount statistics
Publication Date: 2026.03.12 HANGZHOU DIANZI UNIV
  • US20260073075A1 patent drawing

AI summary

Provided is a privacy-preserving method for personal bill record filtering and amount statistics. A user homomorphically encrypts data involved in personal bills, including bill amount, income-expenditure category, bill description, and occurrence time, and uploads ciphertext data to a server. Then the user inputs three conditions: keywords for the bill description, an interval for the bill amount, and an occurrence time range. The server, according to an AND/OR combination of the three conditions, performs a combination of homomorphic operations on the ciphertext data, and returns all results to the user, and the user performs decryption to recover query results. Finally, the user inputs a required income-expenditure category and a required occurrence time range. The server performs homomorphic operations and returns operation results to the user. The user performs homomorphic decryption to calculate a total amount, thereby completing amount statistics and generating a final query result.