DMA Controller Shuffling Unit for Security
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Solution Overview
Problem
Direct memory access (DMA) systems are vulnerable to external attacks that can gather information from timing and energy consumption features of block move operations, necessitating enhanced security measures.
Innovation Solution
Incorporating a shuffling unit that randomizes the order of memory access addresses, either by using a lookup table, adding dummy addresses, or altering least significant bits, to create different timing and power consumption patterns, thereby enhancing security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DMA controller accesses memory in sequential order, then access efficiency is high, but security is compromised due to predictable timing patterns
Solution Approach 1:
The patent applies preliminary action by pre-generating multiple random access order patterns and storing them in a lookup table before DMA operations begin. The shuffling unit selects and applies a predetermined random pattern from this table, allowing the system to maintain high access efficiency while ensuring security through pre-planned randomization strategies.
Solution Approach 2:
The patent implements dynamics by making the memory access order changeable and adaptive. Instead of fixed sequential access, the system dynamically selects from multiple random access patterns stored in the lookup table, allowing the access sequence to vary while maintaining predictable performance characteristics through the pre-computed patterns.
2Reliability
If DMA controller adds shuffling unit for randomization, then security is enhanced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the shuffling function into distinct modular components: a lookup table storing random patterns, a shuffling unit that selects and applies patterns, and the existing DMA controller. This modular segmentation allows the security enhancement to be added as a separate functional block without fundamentally redesigning the entire DMA controller architecture.
Solution Approach 2:
The patent uses an intermediary approach by introducing a lookup table as a mediator between the DMA controller and memory access operations. The lookup table pre-stores random access patterns, acting as an intermediary that provides randomization without requiring complex real-time generation logic within the DMA controller itself, thus reducing overall system complexity.
3Reliability
If DMA controller uses randomized access order, then security against attacks is improved, but access time variability increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing optimal random access patterns in the lookup table during system initialization or idle periods. These pre-computed patterns are designed to provide both security randomization and acceptable performance characteristics, eliminating the need for complex real-time optimization during actual DMA operations.
Solution Approach 2:
The patent applies parameter changes by modifying the access order parameter while maintaining other performance-critical parameters within acceptable ranges. The lookup table stores random patterns that have been optimized to balance security requirements with performance constraints, allowing the system to achieve security enhancement without excessive time variability.
Data Source
AI summary
A method for direct memory access includes: receiving a direct memory access request designating addresses in a data block to be accessed in a memory; randomizing an order of the addresses the data block is accessed; and accessing the memory at addresses in the randomized order. A system for direct memory access is disclosed.