Commutative Encryption for Privacy-Enhanced Data Set Comparison
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Solution Overview
Problem
Conventional systems for sharing and comparing sensitive data sets face vulnerabilities such as unintended disclosure and phonebook attacks, which compromise privacy and security, especially when using irreversible cryptographic algorithms.
Innovation Solution
A method involving keyed commutative encryption functions, where each data set is encrypted using its private key and the keys of other sets, allowing for privacy-enhanced comparison without direct communication between parties, reducing susceptibility to attacks and maintaining data secrecy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If irreversible cryptographic algorithms (one-way functions) are used to obfuscate sensitive data, then data confidentiality is protected, but the system becomes vulnerable to phonebook attacks that can reveal private data
Solution Approach 1:
The patent applies preliminary action by performing commutative encryption with multiple keys before data comparison. Each party encrypts the other's encrypted data with their own key, ensuring that even if one party's data is compromised, the multiple layers of encryption prevent phonebook attacks from succeeding. This preliminary encryption layering occurs before any comparison or matching operations.
Solution Approach 2:
The patent uses composite materials by combining multiple encryption keys and commutative encryption functions to create a multi-layered security structure. Instead of relying on a single cryptographic algorithm, the system composite multiple encryption layers (E1(E2(E3(data)))), where each layer provides additional security against phonebook attacks while maintaining the ability to perform secure comparisons.
2Reliability
If reversible encryption methods are used to maintain data confidentiality during transfer, then data security is improved, but decrypted data becomes subject to potential loss or unauthorized use
Solution Approach 1:
The patent applies preliminary action by performing all necessary encryption and comparison operations before any data is decrypted. The commutative encryption ensures that data remains encrypted throughout the entire comparison process, and only the final matching results (not the raw data itself) are decrypted and shared, preventing unauthorized data use while maintaining security during transfer.
Solution Approach 2:
The patent extracts only the essential matching information from the encrypted data sets without extracting or exposing the underlying sensitive data. By working entirely in the encrypted domain and only decrypting match results (not the source data), the system extracts the necessary information while leaving the sensitive data protected, thus preventing unauthorized use after decryption.
3Ease of operation
If conventional hashing schemes are used for data comparison, then data can be compared for matching, but parties can perform phonebook attacks to reveal nearly all PII in the other party's dataset
Solution Approach 1:
The patent uses composite materials by layering multiple commutative encryption functions with different keys on top of the hashing/comparison operation. Instead of using plain hashing, the system creates a composite structure where data is encrypted with key1, then key2, then key3, allowing comparison to proceed on the encrypted layers while preventing phonebook attacks from revealing PII, thus maintaining both comparison capability and privacy.
Data Source
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AI summary
The invention relates to a computer implemented method, a computer system and a computer program for privacy enhanced comparison of a plurality of data sets. The method comprises the steps of: - allocating a private encryption key to each of the data sets, - an encryption step being performed for each of the data sets, the encryption step comprising generating a commutatively encrypted data set of the respective data set, wherein the commutatively encrypted data sets are generated by successively applying a keyed commutative encryption function on the respective data set with the private encryption key of the respective data set itself and with the private encryption keys of the other data sets, - comparing the commutatively encrypted data sets.