Context Switch Controller for Shared Cryptographic PAPU
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Solution Overview
Problem
Conventional cryptographic systems for multi-channel radio systems are costly, heavy, and voluminous due to the need for a dedicated programmable algorithm processing unit (PAPU) for each physical channel, which is inefficient for systems with many channels, and they lack effective methods to support multiple independent levels of security (MILS).
Innovation Solution
A cryptographic system utilizing a context switch controller allows a single PAPU to process multiple channels by switching its processing state through a rigid sequence of operations, ensuring secure data separation between channels, thus achieving MILS compliance with reduced hardware requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated PAPU is allocated to each physical channel, then security separation between channels is ensured, but system cost, weight, and volume increase significantly
Solution Approach 1:
Multiple dedicated PAPUs are merged into a single shared PAPU that serves multiple channels. The context switch controller manages the sharing by switching the PAPU between different channels and security contexts, eliminating the need for separate hardware instances while maintaining security separation through controlled access and context isolation.
Solution Approach 2:
A single PAPU is designed to perform multiple functions by serving different channels and security levels. The PAPU becomes a universal cryptographic processing unit that can be dynamically allocated to different channels based on security requirements, rather than being dedicated to a single channel.
2Reliability
If a dedicated PAPU is allocated to each physical channel, then security separation between channels is ensured, but system cost increases
Solution Approach 1:
Multiple dedicated PAPUs are merged into a single shared PAPU that serves multiple channels. The context switch controller manages the sharing by switching the PAPU between different channels and security contexts, eliminating the need for separate hardware instances while maintaining security separation through controlled access and context isolation.
Solution Approach 2:
A single PAPU is designed to perform multiple functions by serving different channels and security levels. The PAPU becomes a universal cryptographic processing unit that can be dynamically allocated to different channels based on security requirements, rather than being dedicated to a single channel.
3Reliability
If a dedicated PAPU is allocated to each physical channel, then security separation between channels is ensured, but system volume increases
Solution Approach 1:
Multiple dedicated PAPUs are merged into a single shared PAPU that serves multiple channels. The context switch controller manages the sharing by switching the PAPU between different channels and security contexts, eliminating the need for separate hardware instances while maintaining security separation through controlled access and context isolation.
4Weight of stationary object
If a single PAPU is shared across multiple channels, then hardware cost and size are reduced, but security separation between channels may be compromised
Solution Approach 1:
A context switch controller is introduced as an intermediary between multiple channels and the single PAPU. This mediator manages the PAPU's allocation to different channels, enforces security policies, and ensures proper context switching. The controller acts as a gatekeeper that prevents unauthorized access and maintains security separation despite the shared hardware resource.
Solution Approach 2:
The PAPU's assignment to channels is made dynamic rather than static. The context switch controller can dynamically allocate the PAPU to different channels based on current security requirements and channel priorities. This dynamic management allows the system to adapt security allocations in real-time while using a single shared resource.
5Adaptability or versatility
If context switching is implemented without a rigid sequence of operations, then flexibility is improved, but data leakage between channels may occur
Solution Approach 1:
Before switching contexts, the system performs preliminary actions to ensure security. This includes flushing any remaining data from the PAPU, validating the security context of the incoming channel, and preparing the appropriate security parameters. These preliminary actions prevent data leakage while allowing flexible context switching.
Solution Approach 2:
The context switch controller implements feedback mechanisms to monitor and control the PAPU's state during context switching. The system continuously checks security conditions, validates context transitions, and adjusts switching behavior based on security requirements. This feedback ensures that flexibility does not compromise security.
Data Source
AI summary
A cryptographic system, method, and device for implementing cryptographic functions designed to protect data is provided. The method includes (a) providing an algorithm processing unit, (b) executing a cryptographic algorithm at the algorithm processing unit using a first cryptographic datum and input data to form output data, (c) determining if a context switch command is received from a controller, (d) receiving a second cryptographic datum from a memory if the context switch command is received, (e) replacing the second cryptographic datum with the first cryptographic datum if the context switch command is received, and (f) repeating (b)-(e). The controller switches the processing state of the algorithm processing unit from one channel to another channel without leaking data between channels through execution of the operations each time a channel switch is selected. As a result, a single algorithm processing unit used with a controller can provide multiple independent levels of security.