Symmetric-key Encryption Preserving Data Format in ECB Mode
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Solution Overview
Problem
Existing encryption methods fail to securely preserve the format and syntax specifications of digital data during encryption, particularly in the ECB mode of operation, leading to issues with variable data sequence lengths, statistical weaknesses, and information leakage.
Innovation Solution
A symmetric-key encryption method that iteratively generates keystream symbols and ciphertext symbols, ensuring compliance with data format and syntax rules by modifying keystream generators to depend on both the secret key and the plaintext or ciphertext sequence, using techniques like plaintext or ciphertext memory to preserve variable data format and syntax rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional stream ciphers are used in ECB mode, then encryption speed is maintained, but security performance deteriorates due to inability to securely handle repeated encryptions with the same key
Solution Approach 1:
The keystream generator is made dynamic by introducing plaintext memory, where the generation of each keystream symbol depends on previous plaintext symbols. This dynamic dependency ensures that repeated encryptions with the same key produce different keystream sequences, securing ECB mode operation while maintaining encryption speed through efficient iterative generation.
Solution Approach 2:
The patent implements feedback mechanisms where previous plaintext or ciphertext symbols are fed back into the keystream generation process. This feedback creates a dependency chain that prevents statistical weaknesses in ECB mode, as each encryption operation's security is linked to previous operations through the feedback loop, thereby improving security performance without sacrificing speed.
2Adaptability or versatility
If encryption methods preserve data format and syntax specifications, then compatibility is improved, but complexity of the encryption algorithm increases
Solution Approach 1:
The patent applies preliminary actions by pre-defining syntax rules and format specifications before the encryption process. The keystream generator is configured in advance to be aware of these constraints, allowing it to generate symbols that automatically comply with syntax rules. This preliminary configuration reduces the need for complex post-processing and simplifies the overall algorithm while maintaining format compatibility.
Solution Approach 2:
The encryption algorithm applies local quality by treating different positions in the data sequence differently based on syntax rules. Each symbol's encryption is customized according to its position and the requirements of surrounding symbols, allowing format preservation without requiring a complete redesign of the encryption algorithm. This localized approach maintains simplicity while achieving adaptability.
3Manufacturing precision
If syntax rules verification is performed during encryption, then data format compliance is improved, but processing time increases
Solution Approach 1:
The patent ensures continuity of useful action by integrating syntax rules verification into the continuous keystream generation process. Rather than performing separate verification steps that would interrupt encryption, the syntax compliance is checked continuously alongside keystream symbol generation. This allows format compliance to be maintained without adding significant processing time, as the verification is performed in parallel with the encryption operation.
Data Source
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AI summary
Symmetric-key encryption method (200) for transforming a sequence of plaintext symbols (x) into a sequence of ciphertext symbols (y), the method including an iterative encryption process comprising: computing (202, ST-ALT) an altered current internal state by combining a current internal state with a current memory symbol; computing (202, ST-NXT) a next internal state from said altered current internal state; generating (202, KEY-OUT) a keystream symbol (z) from said next internal state; verifying (203) whether said generated keystream symbol satisfies a condition related to data-format/syntax rules; iteratively (204, 202) computing next internal states and iteratively generating keystream symbols; iteratively encrypting (205, 206, 208) plaintext symbols by employing next keystream symbols to obtain the sequence of ciphertext symbols (y).