For over a decade, Proof of Personhood (PoP) methods like BrightID, Worldcoin, Idena, and passport scans have been chosen based on intuition and private testing. Millions of dollars in quadratic funding, DAO treasuries, and basic income have flowed through verification systems with no shared benchmark for how expensive they are to break.
The Missing Number: Price of Forgery
A new paper posted on ethresear.ch argues the only objective measure is one set by the market. The Price of Forgery (PoF) is defined as the dollar amount required to forge an identity that a given verification method will accept. It's objective because whoever is cheapest at forging sets the price—no committee, no expert panel needed. To actually discover that number, the paper describes the Upala protocol, where any user can voluntarily mark their own identity as Sybil in exchange for money, and the Gentle Methodology, a dual auction over score and pool size that walks the market upward in small steps until forgers reveal the price.
Why This Isn't Just Paying Bots
The paper dedicates a section to common misconceptions that have accumulated over the years. You've probably heard them: "but you're paying bots," the bot tragedy of the commons, whether this is just oligarchy with extra steps, and the avalanche-exit or bank-run worry. The response is that Upala isn't a PoP method itself—it sits underneath them, providing a cost floor. The price is only meaningful because forgers compete to undercut each other, and the market's incremental steps prevent a single point of collapse.
What This Enables Next
If the Upala protocol finds traction, project treasuries might finally have a single number to compare verification methods: the cheapest cost to break them, set by the cheapest forger. That would replace hand-waving with a dollar figure, making Sybil resistance accountable to the market rather than to intuition.
Source: The Price of Forgery: measuring Sybil resistance in dollars (a paper)
Domain: ethresear.ch
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