Trusted Execution Environment Offline Management Policy

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Solution Overview

Problem

In offline scenarios, trusted execution environments (TEEs) lack the capability to distinguish between legitimate and malicious use of valid offline management instructions, leading to potential resource occupation by malicious applications, which can result in replay and Denial of Service (DoS) attacks.

Innovation Solution

The TEE generates an offline management policy based on parameters such as usage duration and quantity thresholds, allowing it to actively prevent malicious occupation of resources by managing security domains (SDs) and trusted applications (TAs) installed or updated according to the policy, thereby enhancing security and preventing unauthorized access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the TEE executes offline management instructions with authorization verification, then the authorization verification problem is resolved, but malicious applications can still occupy TEE resources by using valid offline management instructions

Engineering Contradiction:
Improveauthorization verificationVSAvoidmalicious resource occupation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by establishing usage policies and constraints before executing offline management instructions. The TEE pre-defines usage durations, quantity thresholds, and behavioral constraints for TAs, then automatically enforces these constraints during execution. This prevents malicious resource occupation by validating usage patterns against pre-established policies, allowing the TEE to reject instructions that would violate usage constraints even if authorization verification passes.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the TEE accepts multiple different offline management instructions, then the TEE can execute valid instructions, but it cannot identify whether the use behavior of these instructions is valid

Engineering Contradiction:
Improveexecution of multiple instructionsVSAvoidinstruction usage validity
Core Design Contradiction:
Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements feedback mechanisms by continuously monitoring TA usage patterns and comparing them against predefined usage policies. The TEE tracks execution counts, monitors usage duration, and validates behavioral patterns of each TA. When usage exceeds predefined thresholds or violates constraints, the system provides feedback by rejecting further instructions or triggering security responses. This feedback loop enables the TEE to distinguish between legitimate and malicious usage of valid offline management instructions.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3737129B1Management method for offline management instruction and terminal
Publication Date: 2023.08.30 HUAWEI TECH CO LTD
  • EP3737129B1 patent drawingFigure 1
  • EP3737129B1 patent drawingFigure 2
  • EP3737129B1 patent drawingFigure 3

AI summary

Embodiments of the present invention provide an offline management instruction management method and a terminal. The management method includes: receiving, by a TEE of a terminal, an offline management instruction sent by an REE of the terminal, where the offline management instruction includes an offline management parameter, and the offline management parameter includes at least one of a usage duration threshold and/or a usage quantity threshold; executing, by the TEE, an offline management operation corresponding to the offline management instruction, and generating an offline management policy based on the offline management parameter; and when a usage status of a security domain SD or a trusted application TA does not meet the offline management policy, deleting, by the TEE, the SD or the TA, or restoring, by the TEE, the SD or the TA to a status before update, where the SD or the TA is installed or updated offline by the TEE according to the offline management instruction. The terminal determines, based on the offline management policy, whether offline management performed by the REE on the SD or the TA meets a case in which a TEE resource is maliciously occupied, so that the TEE of the terminal has an active defense capability.