Secure Execution Environment for IoT Device Security
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Solution Overview
Problem
Conventional device management systems assume software integrity and fail to effectively manage devices that have been hacked or compromised, leading to security vulnerabilities, especially in Internet of Things (IoT) devices.
Innovation Solution
A secure execution environment (SEE) is established on a device, separated from the rich execution environment (REE), with a secure watchdog timer and security manager that configures access to peripherals and sensors based on a security policy, enabling secure operations even when the device is offline or compromised, by using a secure channel with a remote security entity for authentication and updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional device management system is used that assumes software integrity, then the system is simple to operate, but the device becomes vulnerable to hacking and botnet operations
Solution Approach 1:
The system is divided into two separate execution environments: a Rich Execution Environment (REE) for general application execution and a Secure Execution Environment (SEE) for security-critical operations. This segmentation isolates security functions from the main system, allowing the SEE to independently verify software integrity and enforce security policies even when the REE is compromised by malware or botnet operations.
Solution Approach 2:
A security manager is introduced as an intermediary component that bridges the SEE and the external world. The security manager handles authentication, receives security policies from remote entities, and enforces these policies within the device. This intermediary shields the complex security mechanisms from both the user and the potentially compromised REE, maintaining security while preserving ease of operation.
2Reliability
If a secure execution environment with watchdog timer is implemented, then the device can detect and respond to compromises, but the device complexity increases
Solution Approach 1:
The secure watchdog timer is pre-configured with expiration thresholds and associated security policies before the device operates. When the timer expires, the pre-defined security policies are automatically enforced without requiring complex real-time analysis. This preliminary configuration simplifies the runtime operation while maintaining robust security monitoring and response capabilities.
Solution Approach 2:
The secure execution environment implements self-monitoring through the watchdog timer mechanism. The timer automatically detects failures or compromises by expiring when no valid heartbeat or authentication signal is received, and triggers predefined security responses without external intervention. This self-service approach reduces the burden on external security management systems while maintaining high reliability.
3Reliability
If the security manager enforces strict security policies, then unauthorized access is prevented, but the ease of operation for legitimate users may be reduced
Solution Approach 1:
The security manager implements a feedback mechanism where security policies and authentication requirements are dynamically adjusted based on the device's operational state and security context. Legitimate users experiencing authentication issues can receive guidance or have their credentials validated, while truly unauthorized access attempts are blocked. This feedback loop maintains strict security enforcement while preserving ease of operation for legitimate users.
Data Source
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AI summary
A method for establishing and maintaining a security policy for a device can include establishing a secure channel between a secure execution environment (SEE) operating on the device and a security entity external to the device. The method can also include configuring, by a security manager executing on the SEE, access to sensitive operations of an environment interactor coupled to the device based on a security policy provided from the security entity. The method can further include resetting, by the security manager, a secure watchdog timer in response to a reset authorization token provided from the secure entity. If the secure watchdog timer expires a given predetermined number of times since a last reset authorization token is received, the security manager executes a given prescriptive operation dictated by the security policy.