Decentralization is often treated as an intuitive property: more nodes, more validators, more participants. In practice, however, most systems lack a precise way to measure:

Who is actually participating, and how independent are they?

Proof-of-Biometric-Uniqueness (PoBU) treats decentralization as a system property that can be measured. Not at the level of nodes or keys, but at the level of real humans.

How, you ask? Read here: https://x.com/humanode_io/status/2019098536957431935