Value Comparison Tags for Encrypted Numerical Data
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Solution Overview
Problem
Conventional encryption techniques are ineffective in preventing information leakage, particularly when administrators with legitimate access abuse their authority, and existing searchable encryption methods struggle with value comparison processing of numerical data without decrypting it, leading to excessive processing amounts as ciphertext length increases with the number of plaintexts.
Innovation Solution
A value comparison server using additive homomorphism encryption with a processor and memory to generate value comparison tags for numerical values, allowing comparison without decryption by calculating discrete logarithms within a predetermined range, reducing processing amounts and maintaining data encryption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encryption is used to protect data, then data security is improved, but the ability to perform value comparison and sorting operations is lost
Solution Approach 1:
The patent introduces an intermediary mechanism (encryption scheme with additive homomorphism and value comparison tags) that enables comparison operations on encrypted data without decryption. The value comparison tag acts as a mediator that preserves the ability to compare numerical values while maintaining encryption, thus resolving the contradiction between data security and operational capability.
2Reliability
If searchable encryption is used to enable processing on encrypted data, then data security is maintained, but value comparison processing of numerical data becomes difficult
Solution Approach 1:
The patent changes the parameter space by introducing value comparison tags that encode numerical value information in a form suitable for cryptographic comparison. This parameter transformation enables value comparison operations on encrypted data by mapping numerical relationships into the cryptographic domain, thus resolving the limitation of conventional searchable encryption.
3Reliability
If ciphertext length increases with the number of plaintexts to enable secure encryption, then data security is improved, but processing amount becomes excessive
Solution Approach 1:
The patent extracts only the necessary comparison information into compact value comparison tags, rather than processing the entire ciphertext. This extraction approach maintains security while significantly reducing the processing amount, as the comparison operation works on the condensed tag representation rather than the full encrypted data structure.
Data Source
AI summary
A value comparison server holds a first secret key and a plurality of tags corresponding to values, each of the plurality of tags is a ciphertext obtained by encrypting each of the values with an additive-homomorphic encryption scheme by using secret keys including the first secret key and a first parameter, a plaintext space has remainder operation with a natural number as modulo in the encryption scheme, and the value comparison server generates a value used for comparing two values corresponding to two tags included in the plurality of tags from the first secret key and the two tags by using the additive homomorphism; and determines which of the two values is greater or equal, on the basis of whether a discrete logarithm of the generated value to the first parameter can be calculated within a value of a predetermined range.