Vitalik Buterin, the co-founder of Ethereum, expressed his concerns in a new blog post on Monday about Worldcoin, a new cryptocurrency created this week by OpenAI CEO Sam Altman.In the article, Buterin identifies four key problems with the “Proof-of-Personhood” (PoP) scheme used by Worldcoin.y

According to Worldcoin, user authentication can be performed without the need for personal data storage or a centralized authority. Users have to scan their iris with the “Orb” gadget to receive a “World ID”. Compatible applications can use the network of verified Worldcoin users to customize their services and filter out bots, such as a company’s own wallet app.

In his blog, Buterin argues that this system may have problems with centralization, accessibility, privacy, and security.

Buterin first makes the argument that iris scans can inadvertently reveal more information than intended. For example, if someone scans the iris of a World ID holder, they can compare the results with the Worldcoin database to at least find out if that person is registered in the system. In addition, Buterin claims that due to the difficulty of obtaining an Orb device, World IDs will not be available to everyone.

In addition, Buterin argues that since Sphere is hardware, “we have no way to verify that it was designed correctly and has no backdoors.” The Worldcoin Foundation “remains able to insert a backdoor into the system, allowing it to create an arbitrary number of fake human identities,” the author continues.

Finally, Buterin raises the issue of Worldcoin security due to the possibility of hacking users’ phones and forcing users to provide iris scans.

Buterin agrees that there is no perfect solution to these problems. There is no perfect way to show someone’s personality, Buterin argues. Instead, we have “at least three different paradigms of approaches, each with their own advantages and disadvantages.” The terms “social graph-based,” “general hardware biometrics,” and “specialized hardware biometric solutions” (such as Worldcoin) refer to these three methods.

Buterin also notes that Worldcoin has made hardware advances that differentiate it from more traditional identification systems, especially in terms of user privacy. It turns out that specialized hardware solutions can be quite effective in protecting privacy, Buterin adds. The downside of this, however, is that specialized hardware systems cause more serious centralization issues.