Proof of Personhood (PoP)

Idena is a blockchain that prioritizes fairness and prevents concentration of power. In Idena, each individual is assigned one node (and wallet), which means that no one can gain an advantage in acquiring block generation rights.

The system that enables this is called Proof of Personhood (PoP). In PoP, each node owner proves their "personhood" by solving a puzzle called a "flip". Flips are designed to be difficult for computers to solve and can only be solved by humans.

The crucial aspect is that these flips are conducted "simultaneously" at predetermined times. The time given to answer the flips is very short, so it is impossible for a human to solve flips for multiple nodes at once. Therefore, managing multiple nodes by a single individual becomes difficult.

For more information, you can refer to the Citizen Revision Proposal and the Idena Network - How To Make A Good Flip guide. Additionally, you can find the Opening of Idena Flip and the Proof of Personhood Report.

In response to a question raised by Paula from the Democracy Earth Foundation, shogochiai from Cryptoeconomics Labs provided an answer. You can find the response here(https://t.co/MfhAhO7x2Q). The CryptoTimes_mag also shared this response on January 30, 2021(https://twitter.com/CryptoTimes_mag/status/1355461464807510025?ref_src=twsrc%5Etfw).