Ethereum co-founder Vitalik Buterin has issued critical warnings about the digital identity project World (WLD), previously known as Worldcoin, which is led by Sam Altman. While World has gained traction with over 13 million unique users and utilizes zero-knowledge (ZK) technology to protect biometric data, Buterin cautions that its "per-person identity" system could erode online anonymity and privacy.
In two statements published on June 28, 2025, Buterin outlined both the benefits and significant risks of digital ID systems that rely on a single identity per individual. He explained that even with ZK proofs, such systems risk linking all online activity to one identity, potentially enabling coercion or surveillance. Buterin emphasized that this approach compromises pseudonymity—an important internet freedom—and warned that dominant universal ID systems could suppress users' ability to maintain multiple accounts or identities.
Buterin also noted practical limitations with current ID frameworks, such as exclusion of stateless individuals and vulnerability to biometric spoofing. He proposed a "pluralistic identity" model that avoids centralization by allowing multiple entities to provide identities. This approach could include community-based attestations or diverse login methods, enhancing resilience and privacy by preventing any single system from monopolizing users' identities.
Despite criticisms, the World project continues expanding, including plans for a Visa card and user authentication pilots with companies like Tinder in Japan. Buterin urges the crypto community to focus on pluralistic, decentralized identity frameworks that foster privacy, inclusion, and user choice rather than seek universal digital IDs.