Dynamic Bit Inversion for Secure Searchable Encryption
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Solution Overview
Problem
Existing searchable encryption technologies face challenges in maintaining both high searching performance and security, particularly when encrypting data with the same noise, which can lead to inference of pre-encryption data from frequency analysis.
Innovation Solution
An information processing apparatus and method that generates an encrypted bit string using keyed hashing, dynamically inverts a predetermined number of bits based on a random number, and sends inverted-bit-number information, enabling secure and efficient information searches by comparing bit counts and magnitudes between the encrypted keyword and index.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the same noise is added to encrypted data with the same contents, then the encryption process is simple and fast, but the pre-encryption data can be inferred from frequency analysis of encrypted data
Solution Approach 1:
The patent applies dynamics by making the noise component variable rather than fixed. Each encryption operation uses dynamically generated noise values that change based on the encryption context, ensuring that even identical plaintext encrypts to different ciphertexts. This dynamic noise generation maintains encryption speed while preventing frequency analysis attacks.
Solution Approach 2:
The patent changes the parameter of noise values from static to dynamic. By modifying the noise generation mechanism to produce different noise values for each encryption operation, the system maintains computational efficiency while achieving semantic security. The noise values are transformed from constant parameters to variable parameters that prevent pattern recognition.
2Reliability
If dynamically generated random numbers are used to invert bits, then the security level is improved by preventing frequency analysis, but the encryption process becomes more complex
Solution Approach 1:
The patent segments the encryption process into distinct functional modules: keyed hashing for keyword encryption, random number generation for noise creation, and bit inversion for security enhancement. This segmentation allows each component to be optimized independently, managing overall system complexity while maintaining high security through the combination of these modular operations.
Data Source
AI summary
There is provided an information processing apparatus that generates an encrypted bit string in which a hash value calculated by using keyed hashing from a keyword for an information search is mapped into a bit string having a predetermined length, selects a predetermined number of bits from the encrypted bit string on the basis of a dynamically generated random number, inverts the predetermined number of selected bits, and sends the encrypted bit string and inverted-bit-number information to an external apparatus. The inverted-bit-number information indicates a number of bits inverted by a bit inverting unit.