TL;DR

• Human Passport, previously Gitcoin passport, was born from the Gitcoin community to defend Gitcoin Grants from Sybils.

• We still protect every round — including GG23. How we protect rounds has changed over the years, but more recently we’ve been using our proprietary Sybil detection machine learning models, now under the brand of Human Passport.

• Your support in GG23 will help us build new tools like Passport Embeds and multi-wallet Stamps, making it easier than ever to prove your unique humanity.

Support Human Passport here: https://explorer.gitcoin.co/#/round/42161/863/6

Gitcoin Grants Round 23 is live, and once again, Human Passport is on duty! As you read this, our models are working quietly in the background to make sure matching funds aren’t manipulated by Sybils and other bad actors. Because democratized funding only works if you can trust the system.

In this blog, we’ll break down Gitcoin Grants and their defense, revisit Human Passport’s origins, evaluate where we are today, and what’s coming next.

What are Gitcoin Grants

Gitcoin Grants are a community-centric funding program that allocates pooled resources to builders, public goods, and other impact-driven projects. Through a novel pool matching method first proposed by Vitalik Buterin, Zoe Hitzig, and E. Glen Weyl in their Flexible Design for Funding Public Goods paper, grants rounds are governed entirely by the community.

Enter: Quadratic Funding

Quadratic Funding (QF) underpins the matching mechanism that allocates more funds to projects with broader community support, amplifying small donations (starting from $1) from many over large donations from a few. This revolutionary algorithm helps democratise the system and fund what matters most.

You can watch the quick guide to Quadratic Funding by Gitcoin on YouTube.

In quarterly rounds since 2019, Gitcoin has disbursed over $68M in public goods funding. But the impact transcends monetary value - projects like Optimism found early footing through Gitcoin Grants and later went on to fund the matching pool themselves.

Evolving from a funding platform, Gitcoin has transformed into a comprehensive funding protocol that empowers projects and builders to independently create and govern their own funding programs.

But the public funding programs are only as good and fair as their fraud defense.

The Sybil problem

The outcome of Gitcoin Grants depends on the integrity of Quadratic Funding, where the number of donations matters more than the amount. It poses the obvious question: what if somebody decides to cheat and split their donation across many accounts?

Sybil defense is critical to protecting the democratic structure of Quadratic Funding, preventing attackers from gaming the system by making one person appear as many.

The straightforward solution is one-person-one-vote. However, this mechanism has to be carefully designed to make it harder and costly for Sybil attackers, while simple and accessible for real humans, without false positives.

And even then, it may not be enough. In QF, attackers can also collude across multiple real identities, making the problem even harder. Collusion happens when a group coordinates to donate not out of genuine support, but to manipulate the outcomes.

To address this, Gitcoin doesn’t rely on a binary ‘yes/no’ for identity. Instead, it treats Sybil resistance as a spectrum by deploying a multi-layered defense. Human Passport plays a key role in this system, providing modular, sovereign proof-of-personhood to complement Gitcoin’s fraud detection and cluster analysis models.

Human Passport protects Gitcoin Grants

Given Sybil defense is evolutionary, Passport has continuously iterated its approach to be rigorous, yet accessible to real humans.

In the past, most Gitcoin rounds were protected through Passport’s aggregated credential stamp model, where users collect stamps from different identity providers to attain a threshold human score to qualify for the matching pool. These stamps also ensured wider ecosystem unlocks such as rewards and airdrops.

Model Based Detection

To further improve the user experience, and reduce friction, Passport has implemented Model Based Deduction, a data analysis tool that can analyze any EVM address passively. Here, Passport analyzes the onchain history of addresses and compares it to the historical data of verified humans and Sybil addresses. Based on the analysis, the model assigns each address a score ranging from 0 to 100, where a score closer to 0 indicates a higher likelihood of the address being a Sybil, and a score closer to 100 suggests a higher probability of the address belonging to a real human. This method removes user interaction by passively analyzing wallets in the background, without requiring users to manually collect stamps.

Model Based Detection works very effectively when combined with Connection-Oriented Cluster Match (COCM), which is an enhancement to Quadratic Funding that defends against Sybil attacks and collusion by prioritizing genuine, diverse community support. COCM works by analyzing the connections between donors and reducing matching for projects backed by tightly coordinated groups, while boosting those supported by socially diverse clusters. This combination synergistically defends Sybil attack, with better user experience.

Below is a Sybil cluster identified during one of the Gitcoin Grant rounds. Source: Gitcoin Blog

Model Based Detection by Human Passport and COCM by Gitcoin are what is used for protecting the grants today. If you’re curious, you can read more about how Gitcoin protects Grants in their blog post. If you prefer audio experience, our DevRel and Growth Lead, Daniel, recently explained our Sybil defense setup on an X Space with Gitcoin.

Human Passport plays a major role in Sybil-prevention for Gitcoin Grants today — just like it has since the very beginning. Let’s take a closer look at how this collaboration began.

Passport was born from Gitcoin Grants

Human Passport was previously known as Gitcoin Passport and Passport XYZ.

Originating from the Gitcoin ecosystem, Passport was first developed by the Gitcoin team to help protect the Grants program from Sybils manipulating matching pools.

Over the years, Passport leveled-up, incorporating new Stamps, launching new products, and making it faster, cheaper, and easier to verify unique humanity. We’ve built out additional tooling to enable users to push their Passport onchain and for partners to customize the experience around their ecosystem’s unique needs. These enhancements opened up Passport to a variety of use cases beyond Quadratic Funding, including protecting rewards systems, governance tooling, community management platforms, and optimizing AI products.

In 2024, with Gitcoin’s increasing focus on Grants programs and Passport’s expanded list of supported applications, Passport was spun out to form Passport XYZ. During this phase, Passport enjoyed strong user growth from new partnerships and explored additional tooling, such as the Model Based Detection, Custom Passport, and developing a suite of data services.

During this brief period when Passport was independent, an incredible opportunity came up – an acquisition offer from Holonym to join forces. Passport accepted this offer, becoming Human Passport. Passport XYZ, previously Gitcoin Passport, rebranded to Human Passport in December 2024.

The acquisition created strong synergies between the two organizations and product suites, with Human Passport bringing strong traction with 2.2 million users and 120 partners, and human.tech (by Holonym) bringing advanced zk technology that will enable Passport to further decentralize and increase privacy and security for users’ proving humanity with the Passport Stamps.

Passport has evolved over the years. Despite the changes in name, we are continuously working towards the same goal and with the same (but expanded) team. Now as part of human.tech, we further enable partners to embrace the natural digital rights of humans by protecting their programs against attackers in a privacy preserving and secure way.

We keep building

Protecting Gitcoin Grants shaped Passport from day one. It pushed us to build fast, think like attackers, and prioritise real-world Sybil resistance. Even after spinning out, that pressure continues to shape how we evolve.

Focused on strengthening Passport’s security and flexibility, we’re rolling out several new features this quarter:

• Passport Embeds: We are heavily prioritizing a new Human Passport offering called Passport Embeds, which will let partners embed Passport’s unique humanity scoring solution directly into their site, so users can verify in-flow. No redirections. Embeds are currently in closed alpha. Partners interested in testing it early can reach out via our inquiry form.

• Multi-Wallet Stamps: Simultaneously, we are also exploring how we can allow linking Stamps from multiple wallets into a single one, which will better serve those users who have different wallets for different use cases.

• Model-Based Detection on Base: We are adding Base into the list of supported chains in our Models API. It will be available for a standalone analysis as well as be a part of our default aggregated model, combining outcomes from several networks.

• Human Network Integration: And as always, we are exploring making Passport more secure. By implementing human.tech’s AVS, Human Network, in the back end of the Stamps-based product, Passport will become more decentralized and quantum secure.

Support our mission

In GG23, we’re both a defender and a grantee. Help us keep web3 human-first Sybil-last. With Passport-protected Quadratic Funding, your contribution truly matters.

Donate to Human Passport!

https://x.com/HumnPassport/status/1907826914661920914

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About Human Passport (formerly Gitcoin Passport)

Human Passport is an identity verification application and Sybil resistance protocol with more than 2M users. It enables users to collect verifiable credentials, or Stamps, that prove their identity and trustworthiness without exposing personally identifying information. To date, Human Passport has protected over $380M in airdrop and grant funds.

https://passport.human.tech

About human.tech

human.tech is a suite of technologies designed to enhance personal freedom, privacy, and financial autonomy. human.tech provides innovative solutions for secure identity, data ownership, and private transactions, ensuring that technology remains a tool for human empowerment.

https://human.tech