White-Box Cryptographic Implementation Patching Without Key Change
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Solution Overview
Problem
In white-box cryptography implementations, maintaining security without changing cryptographic keys is challenging, especially in environments where attackers have complete control and can modify software, making it difficult to prevent key extraction and distribution.
Innovation Solution
Implementing a k-refreshable white-box cryptographic system that uses unused portions of the cryptographic implementation for different message sets, allowing the system to be patched without changing the underlying cryptographic key, by defining message groups and modifying the implementation to use specific parts of the system based on message associations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cryptographic implementation is patched to renew security, then security is improved, but the cryptographic key must be changed which disrupts system functionality
Solution Approach 1:
The cryptographic implementation is segmented into multiple distinct portions, each capable of processing messages from specific message sets. This segmentation allows the system to use different portions for different message sets, enabling security renewal without changing the key.
Solution Approach 2:
The system dynamically selects which portion of the cryptographic implementation to use based on the message set being processed. This dynamic behavior allows the implementation to adapt and renew security by switching to unused portions while maintaining the same cryptographic key.
2Reliability
If the cryptographic implementation is obfuscated to prevent key extraction, then security is improved, but the complexity of the implementation increases
Solution Approach 1:
The obfuscated implementation is divided into multiple portions, each handling specific message sets. This segmentation allows the system to maintain high security through obfuscation while managing complexity by organizing the implementation into distinct, manageable segments.
Solution Approach 2:
Different portions of the implementation have different obfuscation characteristics tailored to their specific message sets. This local quality approach allows each portion to be optimized for its specific function while contributing to overall security.
Data Source
AI summary
A method of patching a cryptographic implementation without changing a key in a cryptographic system, including: sending a message from a first message set to the cryptographic implementation, wherein the first message uses a first portion of the cryptographic implementation; deciding to patch the cryptographic implementation; sending a second message from a second message set to the cryptographic implementation after deciding to patch the cryptographic implementation, wherein the second message use a second portion of the cryptographic implementation that is not used for any messages in the first message set.