Understanding Exit Testing: The Last Mile to Decentralization

Earlier this month, at the EthCC conference in France, Vitalik Buterin put forward a warning view that seemed a bit alarmist, "If Ethereum cannot truly achieve decentralization, it will face a survival crisis in the future."

To this end, he proposed three key test standards to measure whether a protocol has sustainable decentralization capabilities: Walk-Away Test, Insider Attack Test, and Trusted Base Test.

Among them, the "walk-away test" is the most basic and important link, pointing directly to a core issue:

 What is "Exit Test"?

In layman's terms, the essence of exit testing is whether the project allows users to exit, withdraw assets, and interact on the chain by themselves when the development team is completely "out of touch".

From this perspective, it is more like a bottom-line clause that does not emphasize the integrity of daily functions, but rather tests whether a protocol is truly "trustless" under the most extreme conditions.

In fact, as early as 2022, Vitalik criticized the Training Wheels architecture of most Rollups in his blog, bluntly stating that it relies on centralized operation and maintenance and manual intervention to ensure safety. Users who frequently use L2Beat should be very familiar with this. The homepage of its official website shows a related key indicator-Stage:

This is an evaluation framework that divides Rollup into three decentralized stages, including"Stage 0" that is completely dependent on centralized control, "Stage 1" with limited dependence, and "Stage 2" that is completely decentralized,which also reflects the degree of Rollup's reliance on manual intervention in training wheels.

Image source: L2Beat

One ​​of the most core indicators for evaluating the Stage stage iswhether users can withdraw funds on their own without the cooperation of operators?

This question seems simple, but it is actually a fatal problem.

Take a typical example. For the current mainstream Rollups, although they all have similar mechanism designs such as "escape pods", a large number of projects still retain "upgradeable contracts" and even "super administrator" permissions. It seems to be designed for emergency situations, but in fact it is also a window that may evolve into a potential risk.

For example, the team can control the change address of the logic contract through multi-signatures. Even if it is emphasized on the surface that it cannot be tampered with, as long as the backdoor exists, once malicious logic is injected into the upgraded contract, the user's assets can be legally transferred.

This means that if the user's funds are frozen, it will be difficult to recover without bypassing the project party, and the real exit test requires the complete elimination of dependence and intervention paths,

In short, the exit test is the touchstone for testing whether a protocol can be truly decentralized. It is not only about the ability to resist censorship, but also whether users still have asset sovereignty in the face of extreme situations.

 The end of decentralization is "exit capability"

Why BTC and ETH are the first choice for new users and institutions to enter the market.

Because even without Satoshi Nakamoto and Vitalik, Bitcoin and Ethereum can still operate smoothly, so objectively speaking, for incremental users or institutional players, the most core consideration for Web3 entry decision is nothing more than "Can I take my money away at any time?"

The exit test is a direct answer to this question. This is the "last mile" for blockchain to achieve decentralization, and it is also a practical test of the concept of "Not your keys, not your coins". After all, if users must rely on a front-end interface or a development team to withdraw assets or interact, it is essentially still a centralized trust relationship. For a protocol that has truly passed the exit test, even if all nodes are offline and all operators run away, users can still use on-chain tools and third-party front-ends to complete operations independently. This is not only a technical issue, but also the implementation of the Web3 concept. It is for this reason that Vitalik has repeatedly emphasized that many seemingly decentralized DeFi or L2 projects actually contain centralized channels such as upgrade keys, backdoor logic, and freezing mechanisms. Once these mechanisms are abused, user assets will be completely controlled by others.

Exit testing is to verify whether these mechanisms exist and require that they be completely stripped away. Only when the user's exit path does not rely on any party, the protocol is truly trustworthy.

 "Exit test", the watershed for decentralization to become a reality

And if we understand it from another perspective, we will find that although the "exit test" is the core criterion for the security design of Ethereum, especially Rollup, it has actually been widely practiced in other areas of Web3:

Take wallets as an example. As a core tool for asset management, they must have a high degree of security and transparency, which includes key factors such as the randomness of mnemonics and private key generation (true random number generator), secure open source firmware, and almost all mainstream Web3 wallets (such as imToken, etc.) also allow the export of private keys/mnemonics, and users can easily migrate assets to any wallet software or hardware device.

It can be said that this is a natural "exit design":Users do not need to trust the wallet company itself to control their funds forever,so that users are no longer just "experiencers" of Web3 product services, but "owners" who truly have asset sovereignty.

From this perspective, the three core tests proposed by Vitalik this time are actually a complete closed loop:

• Exit test: Ensure that users can redeem themselves after the project stops operating.

• Internal attack test: Whether the system can resist internal malicious or coordinated attacks by developers.

• Trusted computing base test: Is the amount of code that users need to trust small enough and is it auditable?

These three tests together constitute the decentralized "basic framework" for the long-term sustainable development of Ethereum, truly achieving "Don't Trust, Verify".

To put it bluntly, in the Web3 world, "trust" without trust is essentially derived from verifiability. Only through transparent mathematics and algorithms can users feel assured by "Verifying" at any time without worrying about external factors such as the ethics of the project team.

As Vitalik said at the end:

"If we can't do this, Ethereum will eventually become the memory of a generation, like many things that were briefly glorious but eventually became mediocre, and will be forgotten by history."