Searchable Encryption Masking Frequency Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing searchable encryption systems using probabilistic encryption methods are vulnerable to attacks after searching, as the mask of pseudo-random numbers is removed, transitioning from probabilistic to deterministic encryption, and clients use insecure deterministic encryption for search queries, making the system susceptible to frequency analysis and other attacks.
Innovation Solution
The system employs a DB server and clients that use probabilistic encryption with a mask based on a hash value and homomorphic function output, ensuring the search query is encrypted securely and the mask is not removed, preventing frequency analysis and maintaining high security throughout the search process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If probabilistic encryption method is used for searching encrypted data, then data confidentiality is improved, but after searching the mask of pseudo-random number is removed resulting in deterministic encryption which is vulnerable to frequency analysis
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing masks of pseudo-random numbers before the search operation. These masks are used to encrypt search queries in advance, ensuring that even after the search completes, the encrypted data maintains probabilistic encryption characteristics and remains vulnerable to frequency analysis. The masks are prepared beforehand and reused, preventing the transition to deterministic encryption.
Solution Approach 2:
The patent uses masks of pseudo-random numbers as intermediaries between the search query and the encrypted data. These masks act as a mediator that maintains the probabilistic encryption property throughout the search process. The masks prevent direct correlation between search queries and encrypted data, thereby preventing frequency analysis attacks while enabling successful search operations.
2Ease of operation
If deterministic encryption method is used for search queries, then ease of operation is improved, but security is lowered making the system vulnerable to frequency analysis
Solution Approach 1:
The patent applies parameter changes by switching from deterministic encryption parameters to probabilistic encryption parameters for search queries. Instead of using simple deterministic encryption that is easy to implement but insecure, the system uses probabilistic encryption with pseudo-random number masks, which provides both security against frequency analysis and maintains operational ease through automated mask generation and application.
3Reliability
If probabilistic encryption method is used, then data security is improved, but operation control and client/server system become complicated
Solution Approach 1:
The patent applies self-service by enabling the client to autonomously generate and manage the masks of pseudo-random numbers without requiring complex server-side processing. The client independently performs the encryption operations using pre-computed masks, eliminating the need for complex operation control mechanisms on the server side while maintaining high data security through probabilistic encryption.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
In searchable encryption methods having practical performance, each time that data which has been deposited to a server is searched, leakage of the frequency of occurrences of search results or loss of safety of deposited data corresponding to the search results has occurred, resulting in a dangerous situation. In the searchable encryption processing system of the present invention, a data base server retaining data, a registration client which deposits the data into the data base server, and a search client which causes the data base server to search the data collaborate across a network, wherein the registration client, using a probabilistic encryption method which uses a mask using a homomorphic function and a hash value, deposits the encrypted data into the server, whereupon the search client, using probabilistic encryption which uses the mask which uses the homomorphic function for encryption of the search query, outputs the search query and non-corresponding data as search results without causing the data base server to unmask the mask and without allowing the frequency of occurrences of the data corresponding to the search to leak to the data base server.