Tweakable Block Cipher Encryption Using Key Tables

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Solution Overview

Problem

Existing tweakable block cipher encryption algorithms do not provide security in a white box environment, as they are designed for black box security only.

Innovation Solution

A method and apparatus that generate key tables based on seed values to produce secret values for encryption and decryption, using operations like XOR and permutation functions, ensuring security in both black and white box environments without modifying internal logic or structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing tweakable block cipher encryption algorithms are used, then black box security is provided, but white box environment security is not provided

Engineering Contradiction:

Improvewhite box environment securityVSAvoidenvironment compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The encryption algorithm is segmented into multiple distinct components: key table generation module, secret value generation module, and encryption/decryption module. Each module performs a specific function and can be independently implemented or verified, allowing the system to maintain security while adapting to different environmental requirements including white box environments.

Inventive Principle:

Principle #1Segmentation

2Reliability

If key tables are generated based on seed values to produce secret values, then white box security is provided, but system complexity increases

Engineering Contradiction:

Improvewhite box environment securityVSAvoidencryption system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Key tables are generated in advance based on seed values before the actual encryption process. This preliminary action creates pre-computed lookup structures that simplify the runtime encryption operations while ensuring white box security. The key table generation is performed once and can be stored, reducing the complexity of repeated encryption operations.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If permutation functions and XOR operations are used for encryption, then cryptographic security is enhanced, but computational overhead increases

Engineering Contradiction:

Improvecryptographic securityVSAvoidcomputational energy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The encryption system utilizes parameter changes in the form of different secret values derived from key tables for different encryption operations. By changing the secret value parameters dynamically while maintaining the same core algorithm structure, the system achieves strong cryptographic security without requiring fundamentally different computational operations for each encryption, thus managing computational overhead efficiently.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11522675B2Apparatus and method for encryption and decryption based on tweak converter to which key table is applied

Publication Date: 2022.12.06 SAMSUNG SDS CO LTD

AI summary

A method according to one embodiment includes generating one or more key tables based on a first seed value; generating one or more secret values from a tweak value based on the one or more key tables; and performing encryption or decryption using the one or more secret values. An apparatus according to one embodiment includes a key table generator configured to generate one or more key tables based on a first seed value, a secret value generator configured to generate one or more secret values from a tweak value based on the one or more key tables, and an encryptor/decryptor configured to perform encryption or decryption using the one or more secret values.