Biometric Proof of Personhood – Pros and Cons

Proof of personhood refers to systems that can verify someone is a unique real human being online. This has become an important challenge as the internet grows. Bots and fake accounts are used to spread misinformation, manipulate votes, and scam people. Proof of personhood aims to solve this by only allowing real humans to participate.

There are two main ways proof of personhood works today:

Social Graph Verification

This relies on vouching and social connections. If enough people you know confirm you are real, then the system accepts you as validated. This avoids collecting personal biometric data. But it struggles to scale globally, as you need connections in the existing network. It can also expose your social graph publicly.

Biometric Verification

This scans parts of your body to verify you are human. Two types of biometric systems exist:

• General hardware – Using your computer’s camera to scan your face or fingerprint. Easy to deploy but security is weak.
• Specialized hardware – Dedicated devices like Worldcoin’s Orb that scan irises. More secure but not as accessible.

Worldcoin’s Approach

Worldcoin uses iris scanning with their Orb device. This has better privacy as it only stores a hash of the iris scan. The Orb hardware raises centralization risks though.

Pros of Biometrics

• More accessible globally than social graph approaches.
• Can protect privacy by only storing encrypted biometrics.
• Harder to fake than social graph vouching.

Cons of Biometrics

• Hardware like the Orb is not widely available yet.
• Algorithms must be open source to avoid centralization.
• There are risks of government coercion and surveillance.
• Permanent biometric records raise privacy concerns.

Pros of Social Graph Verification

• Doesn’t require special hardware, easier to deploy.
• Avoids biometric data collection.
• Can accommodate pseudonyms and multiple identities.
• Provides a reputation score rather than just pass/fail.

Cons of Social Graph Verification

• Requires pre-existing social connections to join.
• Leaks social graph data publicly.
• Wealthy people can more easily make fake accounts.
• Risk of re-centralizing into a centralized system.

Conclusion

There are merits and risks to both approaches. Combining social graph and biometrics may give the best solution. Biometrics can bootstrap initial global scale access. Long term, social graphs can take over to avoid permanent biometric records. Much more research is still required to find the right balance. But some form of decentralized proof of personhood will likely be an important building block of Web3.