Vitalik: Airdrops have undermined Gitcoin's ideals, and he is considering a plan that does not support retroactive airdrops

This article is from Ethereum founder Vitalik's blog and has been compiled by Chain Catcher.

Last month, Gitcoin launched its 9th round of donation activities, which set a historical record in fundraising, with over 12,000 donors contributing $1.38 million to 812 different projects, reflecting the high enthusiasm of crypto users for emerging projects.
This fervor is partly driven by the airdrop expectations of many users, as several projects, such as Mask Network, previously airdropped tokens to Gitcoin donors. This time, the event also supports ZkSync payments, which have a lower interaction threshold, leading many users to participate in donations to obtain airdrops, even registering multiple accounts to inflate their contributions.
Ethereum founder Vitalik today wrote an article summarizing this round of Gitcoin donation activities and criticized the aforementioned phenomenon.
First, Vitalik pointed out that the most challenging new phenomenon in this round of donation activities is the emergence of large-scale fraud, where some unknown groups registered a large number of accounts attempting to deceive the Gitcoin mechanism and engage in donation activities. Since multiple sponsors match the donation amounts from users, this phenomenon caused sponsors to pay an additional $33,000.
Therefore, Vitalik believes that Gitcoin needs to create algorithms that can prevent malicious manipulation, while also reducing fraud through manual account verification, inviting third-party analysis, and community oversight.
Subsequently, Vitalik took Mask Network as an example, arguing that the project's retroactive airdrop has set a precedent for the industry. Nowadays, many projects hint in forums that users will be airdropped tokens for their donations, which creates two types of motivations for users participating in this Gitcoin donation: "Are you donating because you like the project's funding (within the mechanism) outcomes, or because you expect to gain some (outside the mechanism) outcomes from funding the project?"
"If there exists a long-term model where a project offers retroactive airdrops to Gitcoin donors, then users will feel pressured to donate not primarily to projects they believe are public goods, but to those they think might have tokens in the future." Vitalik pointed out, "This undermines the ideal of using Gitcoin quadratic funding as an alternative token issuance strategy."
To address this, Vitalik detailed a solution called MACI, which has already had its code released on Github. The following section is a partial translation of Vitalik's original text by Chain Catcher:
MACI is a toolkit that allows you to run anti-collusion applications while possessing several key attributes:
The first is correctness; invalid messages will not be processed, and the mechanism's actual output is the result of processing all valid messages and calculating them correctly;
The second is anti-censorship: if someone participates, the mechanism cannot deceive by selectively ignoring their messages and pretending they did not participate;
The third is privacy; no one can see how everyone else is participating;
The fourth is anti-collusion, where participants cannot prove to others how they participated, even if they want to prove it.
Anti-collusion is a key feature, it makes bribery (or retroactive airdrops) impossible because users cannot prove they actually donated or voted for a project.
The technical description of how MACI works is not difficult. Users participate by signing messages with their private keys, encrypting the signed messages with the public key published by the central server, and publishing the encrypted signed messages to the blockchain. The server downloads the messages from the blockchain, decrypts them, processes them, and then outputs the results along with ZK-SNARKs to ensure they are calculated correctly.

Users cannot prove how they participated because they have the ability to send "key change" messages to deceive anyone trying to audit them: they can first send a key change message to change their key from A to B, and then send a "forged message signed with A." The server will reject that message, but no one else will know that the key change message has been sent. Although there is a trust requirement for the server purely for privacy and coercion considerations; the server cannot publish incorrect results by incorrectly calculating or checking messages. In the long run, multi-party computation can be used to decentralize the server to some extent, enhancing privacy and coercion guarantees.
There already exists a quadratic funding system using MACI: clr.fund. It works effectively, although the current proof generation is still quite expensive. Ongoing work is expected to reduce these costs soon.
It should be noted that adopting MACI does come with necessary sacrifices, which will prevent specific projects from rewarding donors, but it still leaves users plenty of room to express their pride in their contributions. Projects can airdrop to all Gitcoin contributors without distinguishing by project and announce they are doing so through links in Gitcoin profiles. However, users can still donate to other projects and receive airdrops. Therefore, this can be said to be within the scope of fair competition.
However, this remains a long-term issue. MACI may not yet be ready for integration in Gitcoin's 10th round of donations. In the upcoming rounds, focusing on strengthening unique identity verification remains Gitcoin's top priority. The Gitcoin team has already taken excellent steps in this direction.
If the Gitcoin team successfully plays a pioneering role in bravely challenging and overcoming these obstacles, we will ultimately achieve a secure and scalable quadratic funding system that can be used for broader mainstream applications.