Babbitt Column | What are the risks of TEE-based projects?

This article does not constitute any investment advice, investment is risky, and you need to be cautious when entering the market!

1. What is TEE?

The Trusted Execution Environment (TEE) is a secure area within the CPU. It runs in a separate environment and runs in parallel with the operating system. The CPU ensures that the confidentiality and integrity of the code and data in the TEE are protected. TEE is more secure than the operating system by using both hardware and software to protect data and code. Trusted applications running in the TEE have full access to the device's main processor and memory, while hardware isolation protects these components from the user-installed applications running in the primary operating system.

In a word, the code and data running in the TEE are confidential and cannot be tampered with.

Second, what are the common TEE programs?

TEE has different implementations on different CPUs:

1. The technology for implementing TEE on Intel's CPU is called SGX.

2, ARM chip, that is, the technology of implementing TEE on the mobile phone CPU is called TrustZone. Since ARM is customized by different manufacturers, there are many practical solutions, such as Kinibi (Samsung), QSEE (Qualcomm), TEE OS (Huawei), Knox (Samsung), etc. Wait

Third, TEE is commonly used in the blockchain field

The most common applications for TEE application blockchains are consensus algorithms and data privacy calculations.

1. High-performance consensus algorithm based on TEE

There are many such applications, so I won't mention specific public chain projects here, so as not to be hacked. Say an Intel example because the principles of other projects are the same. Intel proposed the Poet consensus algorithm based on its own sgx technology. The principle is that all nodes in the TEE environment execute a random number every round. Whose number is the largest, and who is responsible for this round of block. In theory, the TEE data cannot be falsified and trusted, thus ensuring that the random number is fair, thus achieving a consensus across the network.

2 , TEE-based data privacy calculation

Such projects are the most widely used category of TEE, and there are many public links. Most of the projects on the market that claim to solve data privacy calculations are based on this technology.

The principle is relatively simple, because the project side can not solve the problem that the pure software algorithm encrypts the data of multiple parties, so the TEE technology is used to decrypt all the data and put it into the TEE for calculation, and then the TEE outputs the operation result, thereby realizing the privacy calculation.

A typical feature of such a project is that the nodes that are required to run support TEE on the hardware, and the reader can find it on their own.

Fourth, the risk of TEE

The essence of the project based on TEE technology is that it does not do any algorithms, but relies entirely on the security protection of the TEE hardware environment. It executes code and processes data in the TEE, so that the outside world cannot obtain real data or modify the code logic. Therefore, there are two problems:

1. TEE protects the data and code inside as a security box, but who protects the security of TEE? As long as the hacker breaks the protection of TEE, the private key and code inside will be completely controlled. It can be said that the value carried by the entire blockchain will be stolen and destroyed.

2 , because TEE is a hardware-based solution, once a vulnerability occurs, the blockchain network is difficult to repair through a simple code fork upgrade.

In fact, TEE is often seen as a breach of the vulnerability.

In April 2019, Qualcomm's 40 chips had a vulnerability in the TEE, numbered CVE-2018-11976, which allowed attackers to obtain private information and keys stored in the chip's TEE, affecting billions of Android devices.

In 2018, the TEE environment of the Samsung mobile phone was vulnerable. The attacker could execute arbitrary code and obtain the stored password information.

At the GeekPwn conference in 2016, the TEE of Huawei mobile phones was attacked by Shellphish, a security research team from the United States, which could tamper with stored fingerprint data and control the entire mobile phone.

Imagine that a blockchain project relies on TEE for data protection. If a TEE vulnerability is hacked, it is possible that the user's private key and digital currency on the entire network are easily stolen or tampered with! In this regard, there is no way to solve the problem of soft and hard forks.

V. Conclusion

As a technology to protect data privacy and security, TEE has the advantages of low cost and high efficiency. However, due to hardware-based solutions, there are disadvantages that vulnerabilities may be attacked and upgraded.

Therefore, TEE belongs to the transition period, and the technical compromise is helpless. It is suitable for low-value scenarios and it is difficult to carry the high value of the whole network. The real direction in the future depends on pure software algorithms to solve data privacy and computing problems.

About the author: East of Beijing, public number: bjzdblockchain. Micro signal: beijingzhidong. Senior blockchain investor, engaged in technical research work.

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