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Building a Sybil-Resistant Future Using Gitcoin Passport Onchain Stamps

The fragmented digital identity landscape creates barriers for users and developers in building trust and interoperability between identity and credentialing solutions. The article introduces Gitcoin Passport Onchain Stamps built using the Ethereum Attestation Service (EAS) to enable users to add their stamps to the Ethereum ecosystem. Initially, Onchain Stamps will be available on OP Mainnet, with plans to extend Gitcoin Passport to other EVM-compatible chains. With interoperable attestations, projects can select relevant attestations for Sybil resistance and authorizations, advancing the vision of a more interconnected and secure digital identity landscape. Refer to the links at the end of the article to access a tutorial or to get help from the team on using Gitcoin Passport Onchain Stamps in your application.

Fragmented Landscape of Digital Identity

Our identity is not a single, fixed entity that can be presented statically. Rather, it aggregates different aspects of our lives, such as their relationships, roles, achievements, etc. Various entities, such as family members, employers, governments, and other organizations, represent these aspects through different attestations. However, siloed and centralized identity solutions without a standardized and open platform for creating and verifying attestations lead to incomplete and untrustworthy identity solutions.

Similarly, the current digital credentialing and badge-building platforms in both web3 and web2 create fragmentation in the ecosystem, as each platform has its own credentialing method. This results in a complex and confusing landscape for developers and users alike, making it difficult for individuals to manage their identity in a decentralized and secure way. It also makes it increasingly tedious and difficult for developers to manage all the integrations, ultimately hindering trust and interoperability between identity and credentialing solutions.

Fortifying Sybil-Resistance with Attestations on Ethereum

Attestations are digital records that can be used to prove the authenticity of information. Attestations are crucial because they offer a means of establishing trust and credibility online. In the absence of face-to-face interaction or physical presence, it can be challenging to determine the accuracy or reliability of information. Attestations provide third-party validation and a cryptographically signed confirmation of the authenticity of a piece of information, making it easier for others to trust and depend on that information.

The Ethereum Attestation Service (EAS) is a decentralized, open-source platform for creating and verifying attestations on Ethereum. EAS enables anyone to create custom attestation schemas, which define the structure and rules for creating and making attestations.

EAS is the permissionless and composable base layer for coordinating, creating, and registering unique attestation schemas. This allows for interoperability and composability between various attestation protocols and solutions, enabling the attestation layer to evolve over time. Existing Decentralized identifiers (DIDs), verifiable credentials, and claim protocols are attestations built for specific use cases and communities. EAS is the base registry for these attestation providers to help make the ecosystem more composable and interoperable. 


Onchain Stamps in Gitcoin Passport

Gitcoin Passport's Onchain Stamps feature is at the forefront of digital identity verification on the blockchain, focusing on seamless integration with the Ethereum ecosystem. Unlike other identity solutions that may use blockchain technology, Passport stands out due to its comprehensive approach, offering onchain stamps, scoring methods, and flexible Ethereum integration.

Stamps serve as the foundation for identity verification in Gitcoin Passport. They consist of verifiable credentials collected from identity providers and stored in a Passport. Various web2 and web3 identity authenticators provide these stamps, including Guild, Civic, BrightID, ENS, and Proof of Humanity. The Passport system aggregates stamps and assigns weights based  on their cost of forgery and ability to signal unique humanity . These weights are instrumental in calculating the forgery cost of an identity, resulting in a credibility score for potential participants' online identities.

To store Passport and potentially Passport scorer data onchain, the Ethereum Attestation Service (EAS) has been chosen as the ideal solution. This feature provides significant benefits for Passport Holders, enabling them to add their stamps to the Ethereum ecosystem. This enhancement increases the recognition, usability, and value of their Passport credentials, empowering them through seamless integration with the Ethereum Virtual Machine via a user-friendly interface. Integrators also benefit from this feature, as it offers a more secure and reliable system for interacting with onchain verification of credentials, reducing the risk of fraud and technical issues.

EAS is integrated into the OP Stack, the modular open-source tech stack built by the Optimism Collective that powers OP Chainslike OP Mainnet, PGN, Base, and Zora. All future OP Chains deployed will automatically include the EAS contracts at Genesis. At launch, the Gitcoin Passport Onchain Stamps will be available on OP Mainnet, and contribute to the emerging identity ecosystem. You can learn about the Optimism Collective's ongoing efforts at We plan to extend Gitcoin Passport to other EVM-compatible chains, widening our reach and accessibility. 

Interoperable Attestations for a Sybil-Resistant Future in Ethereum

The Ethereum community needs to collaborate to create a more Sybil-resistant future. Attempting to tackle sybil resistance individually will result in a fragmented and endlessly challenging effort. By working together, we can verify a range of unique identity attributes, allowing for greater flexibility and compatibility when assessing the validity of addresses in a more secure and customizable manner. With this interoperability of attestations, projects can select which attestations are most relevant to their needs for Sybil resistance and authorizations enabling:

  1. Trust and Verification: Onchain Stamps can verify participant identities for any collaborative platform. It utilizes a decentralized data source to evaluate each participant's Passport for authenticity. For example, onchain stamps can be immutable proof of earned verified credentials, ensuring voting power is allocated to eligible members in decentralized governance.
  2. Decentralized Applications: In decentralized applications where every unique individual has equal access, Onchain Stamps can verify the uniqueness of each participant's identity. This helps to decrease the risk of manipulation. For example, airdrops can use a combination of onchain stamps to verify recipient’s eligibility.
  3. Access Control: For services that need strict access control, such as certain DeFi protocols, Onchain Stamps can be utilized to verify the identity of users. This helps to ensure that users are authentic and not impersonating someone else. For example, enchain stamps can automate the process where Decentralized Exchanges (DEXs) require users to have a certain level of experience or hold a specific credential to access advanced trading features.

Launching the Gitcoin Passport Onchain Stamps on OP Mainnet takes us closer to this interoperable future. The Optimism Collective is building an economic engine that fuels positive-sum games, and decentralized identity is central to that goal. Decentralized identity not only unlocks democratic governance and innovation but can empower individuals to have greater control over their finances and participate in the global economy on their own terms.

Bringing Gitcoin Passport Stamps to OP Mainnet lays the groundwork for scaling onchain identity and governance. It has the potential to enhance the capabilities of the Citizens' House governance, a key component of Optimism's ecosystem, by contributing attestations as an experiment to build inclusive and open identity primitives that any application across the Superchain and beyond can use. For example, developers can use their reputation to claim 20x testnet ETH from the Superchain Faucet, shifting the resources from less-legitimate users to users with evidence that they are unique and real humans.

Step Up with Onchain Stamps!

By integrating Passport credentials onchain, we contribute to developing a more transparent and trustworthy decentralized identity system. This fosters wider acceptance and integration of Gitcoin Passport within the Ethereum ecosystem and beyond, advancing the vision of a more interconnected and secure digital identity landscape. We must work together as a community to develop a more Sybil-resistant future. By collaborating, we can create a diverse range of attestations, enabling better composability and interoperability in determining the eligibility of addresses in a more secure and customizable way.

Interested in integrating the Onchain Stamps feature for your project? Fill out the Gitcoin Passport Integration Wizard 🛡️ form to collaborate in protecting your community from bots and Sybils with Gitcoin Passport. You can also review this tutorial demonstrating using Onchain Stamps in your application. For more information on devising the best strategies for reading and scoring stamps onchain, you can access the Passport Documentation or join the Gitcoin Passport Guild.

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