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Co-founder of Ethereum Vitalik Buterin Discusses Biometric Proof of Personhood

Ethereum co-founder delves into biometric proof-of-personhood, discussing Worldcoin’s iris scan approach and its challenges.

Key Points

  • Vitalik Buterin explores decentralized proof of personhood in Ethereum community, including Worldcoin’s biometric approach.
  • Worldcoin’s “the Orb” uses iris scans for global personal identification, but faces privacy, security, and ethical concerns.
  • Proof of personhood’s importance: anti-spam, decentralized governance, protection against manipulation, alternative to captchas.
  • Challenges include privacy and centralization risks, but Worldcoin aims for decentralization and anonymity through ZK-SNARKs.

Co-founder of Ethereum Vitalik Buterin recently delved into the topic of biometric evidence of personhood, a subject gaining traction within the Ethereum community. In a blog post published on July 24, 2023, Buterin explores the potential benefits and challenges of decentralized proof-of-personhood solutions.

Addressing the Unique-Human Problem

Buterin defines proof of personhood as a form of real-world identification that verifies a registered account is owned and operated by a genuine person, while preserving the individual’s actual identity. This concept aims to address the “unique-human problem,” and various initiatives like Proof of Humanity, BrightID, Idena, and Circles have emerged to tackle this challenge.

Worldcoin’s Unique Approach

One particularly ambitious project in this space is Worldcoin, founded by Sam Altman, CEO of OpenAI. Worldcoin stands out with its distinctive approach to proof of personhood, relying on advanced biometrics. The project utilizes specialized hardware called “the Orb” to scan users’ iris patterns. With the goal of global distribution, Worldcoin aims to make obtaining a personal identification easier for everyone.

Buterin acknowledges the criticisms faced by Worldcoin, including privacy and security concerns surrounding the use of the Orb, design issues pertaining to its “coin,” and ethical questions regarding certain decisions made by the company. Additionally, broader concerns are addressed, such as the viability of biometrics altogether and the potential risks associated with proof of personhood. These risks include privacy breaches, coercion by authoritarian governments, and the challenge of maintaining security while operating in a decentralized manner.

The Importance and Applications of Proof of Personhood

Buterin emphasizes the value of proof of personhood in solving issues related to anti-spam measures, preventing concentration of power, avoiding dependence on centralized authorities, and minimizing the disclosure of personal information. The absence of proof of personhood makes decentralized governance vulnerable to manipulation by wealthy actors, including hostile governments. Furthermore, Buterin explores the various potential applications of proof of personhood, such as token distributions, voting in decentralized autonomous organizations (DAOs), protection against bots and sybil attacks in social media, and an alternative to captchas for preventing denial-of-service (DoS) attacks.

Challenges and Worldcoin’s Solutions

Despite the potential benefits, Buterin acknowledges the challenges faced by biometric proof-of-personhood systems. These challenges include privacy concerns, accessibility issues, and centralization risks. However, Buterin highlights Worldcoin’s efforts to address these problems. The project is dedicated to long-term decentralization and ensures user anonymity through the use of cryptographic tools like ZK-SNARKs. Additionally, Worldcoin allows auditing of the Orbs to verify their proper construction.


In conclusion, Vitalik Buterin’s blog post provides a comprehensive examination of biometric proof of personhood, weighing its advantages and drawbacks. It presents a fair and balanced perspective, acknowledging the need to address major issues while recognizing the potential for these systems to tackle significant problems.