Feistel Structure Encryption with Key Table Generation
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Solution Overview
Problem
Conventional white box cipher algorithms are inefficient and lack sufficient security, being vulnerable to real-time cryptographic key recovery attacks due to their dependency on underlying algorithms and additional operations required for key protection.
Innovation Solution
An apparatus and method for encryption using a key table generator to produce random values based on a seed value, generating a block encryption algorithm with a Feistel structure, where the number of branches and rounds are determined by the size of the plaintext data block and available memory, respectively, to create an optimized encryption algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional white box cipher algorithms use additional operations to protect cryptographic keys, then security is improved, but encryption efficiency deteriorates (tens of times lower than underlying algorithm)
Solution Approach 1:
The encryption system is segmented into distinct functional components: key table generation module, Feistel structure encryption module, and S-box substitution module. This segmentation allows each component to operate independently and efficiently, avoiding the overhead of conventional white box operations while maintaining security through the structured arrangement of these components.
Solution Approach 2:
The invention changes the fundamental parameters of the encryption approach by using a Feistel structure with configurable rounds and branches, replacing the traditional symmetric key cipher structure. This parameter change enables efficient encryption operations while maintaining cryptographic security through the mathematical properties of the Feistel network.
2Ease of manufacture
If conventional white box cipher algorithms depend on underlying symmetric key cipher algorithms, then implementation is simplified, but adaptability deteriorates (difficulty in providing wide use)
Solution Approach 1:
The Feistel-based encryption apparatus is designed with universal applicability, capable of implementing various encryption standards and configurations through configurable parameters such as number of rounds, branch factors, and S-box selections. This multi-functionality allows the same underlying structure to serve multiple cryptographic purposes without requiring algorithm-specific implementations.
Solution Approach 2:
The encryption system incorporates dynamic configurability where parameters such as the number of Feistel rounds, branch factors, and key table sizes can be adjusted based on security requirements and performance needs. This dynamic adaptation enables the system to optimize between security and efficiency for different application scenarios.
3Ease of operation
If conventional white box cipher algorithms use fixed structures, then implementation is straightforward, but security against real-time key recovery attacks deteriorates
Solution Approach 1:
The system performs preliminary key table generation using secure random values before the actual encryption process. This preliminary action creates a secure foundation that protects against real-time key recovery attacks, as the key material is pre-established through cryptographically secure random generation rather than being derived from predictable operations.
Data Source
AI summary
Disclosed are an apparatus and a method for encryption. The apparatus includes a key table generator configured to generate random values based on a seed value and generate a key table including the generated random values; and an encryptor configured to apply the generated key table to a round function, generate a block encryption algorithm having a Feistel structure based on the round function, and encrypt a plaintext data block based on the generated block encryption algorithm.