TEE Quick Reference Guide: Best Practices from Basic Concepts to Safe Usage

Trusted Execution Environment ( TEE ) has gained significant attention in the fields of cryptocurrency and AI in recent years. This article will introduce developers and readers to the basic concepts of TEE, security models, common vulnerabilities, and best practices for securely using TEE.

What is TEE

TEE is an isolated environment in a processor or data center where programs can run securely without external interference. TEE restricts access to programs and data within the TEE through strict access controls, limiting access from other parts of the system. Currently, TEE has become popular in mobile devices, servers, PCs, and cloud environments.

Typical application scenarios of TEE include:

• Biometric information protection: such as mobile phone fingerprint unlocking
• Hardware Wallet: Protects sensitive information such as recovery phrases

The Security Model of TEE

General workflow of TEE applications:

1. Developers write code and package it into an Enclave image file (EIF)
2. Deploy EIF to run on TEE server
3. Users interact with the application through predefined interfaces.

Potential risk points include: developers, servers, and TEE suppliers.

To eliminate these risks, TEE adopts a repeatable construction and remote proof mechanism:

• Reproducible builds: Ensure that the build results of the same code are consistent across any device.
• Remote attestation: TEE platform signs messages, including program code measurement values and other information.

This allows users to verify the actual code running within the TEE, preventing developers or servers from malicious actions. However, trust in the TEE provider is still required.

Advantages of TEE

1. Performance: Can directly run large models such as LLM.
2. GPU Support: The latest GPUs provide TEE computing.
3. Correctness: Ensure the reliable operation of non-deterministic programs.
4. Confidentiality: Sensitive data such as private keys must be kept invisible.
5. Network Capability: Secure access to external APIs
6. Write permissions: Able to construct messages and send
7. Developer Friendly: Supports Multiple Programming Languages

Limitations of TEE

The TEE program may still have the following issues:

1. Developer Oversight

   • Opaque code
   • Code measurement issues
   • Insecure code
   • Supply Chain Attack

2. Runtime Vulnerabilities

   • Dynamic code and data
   • Unsecure communication

3. Architectural design flaws

   • Attack surface is too large
   • Portability and Activity Issues
   • Untrusted root

4. Operational Issues

   • Platform version is not secure
   • Lack of physical security

Build Secure TEE Programs

The safest solution: no external dependencies

Necessary precautions

1. Treat the TEE program as a smart contract, conduct rigorous testing.
2. Audit Code and Build Process
3. Use audited libraries
4. Verify TEE Proof

Use case related suggestions

1. Ensure secure communication between the user and TEE
2. Note the transience of TEE memory
3. Reduce the attack surface
4. Physical Isolation
5. Multiple Provers

Future Outlook

TEE is becoming an important technology in the AI and cryptocurrency fields. Large tech companies are integrating TEE into their products, and the crypto community also views it as a solution for expanding on-chain applications. TEE is expected to become a bridge for the integration of products from Web3 companies and large tech companies.