Cache Memory Between Decryption Engine and CPU
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Solution Overview
Problem
Existing data security systems for devices like Smart cards face challenges in ensuring secure access to sensitive data, as encryption techniques can be compromised if unauthorized users obtain the decryption key, and memory overhead is high due to inefficient decryption processes.
Innovation Solution
Implementing a cache memory system connected between a decryption engine and a CPU, where encrypted data is decrypted and stored in cache memory, allowing the CPU to access it faster and reducing memory overhead by varying the decryption key based on memory addresses, thus enhancing security and access speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption techniques are used to protect sensitive data in Smart cards, then data security is improved, but the system becomes vulnerable if decryption keys are obtained by unauthorized users
Solution Approach 1:
The decryption key is segmented into multiple parts and distributed across different memory locations. The key material is divided such that no single location contains the complete key, preventing unauthorized access even if one memory location is compromised.
Solution Approach 2:
A secure memory structure acts as an intermediary between the decryption key and the processing units. This intermediary layer controls and monitors access to key material, preventing direct access by unauthorized users while allowing authorized operations.
2Ease of operation
If decryption keys are stored in memory for data access, then data accessibility is improved, but memory overhead increases and security risks arise
Solution Approach 1:
The decryption key is divided into multiple segments stored at different memory locations rather than as a single unit. This segmentation reduces the memory overhead at any single location while maintaining the ability to reconstruct the full key when needed for decryption operations.
Solution Approach 2:
Different portions of the key material are stored with different access characteristics and security levels at different memory locations. This allows optimized memory usage where each location stores only the portion of key material it needs, reducing overall memory overhead while maintaining accessibility.
3Productivity
If direct access to decryption engine is allowed by CPU, then processing speed is improved, but security is compromised
Solution Approach 1:
A secure memory structure serves as an intermediary between the CPU and decryption engine, controlling all access to key material. This intermediary maintains security by preventing direct CPU access to the decryption engine while still enabling necessary decryption operations through controlled interfaces.
Solution Approach 2:
The system implements feedback mechanisms where the secure memory structure monitors and controls access requests to the decryption engine. Access is granted only after verification of authorization, providing continuous security feedback while maintaining processing efficiency.
Data Source
AI summary
This document discloses data security systems and methods of securing data. A cache memory can be connected between a decryption engine and a central processing unit (“CPU”) to increase security of encrypted data that is stored in a datastore. The decryption engine can retrieve the encrypted data from the datastore, decrypt the data, and store the decrypted data in the cache. In turn, the decrypted data can be accessed by the CPU. The data can be encrypted with a secret key, so that decryption can be performed with the secret key. The key can be varied based on a memory address associated with the data. The key can be protected by restricting direct access to the decryption engine by the CPU.