Proof of Personhood

Proof of Personhood (PoP) is a consensus mechanism that digitally verifies an individual’s humanness and uniqueness to protect a blockchain network from identity fraud.

What Is Proof of Personhood?

To help secure blockchain networks, consensus mechanisms like proof of work (PoW) and proof of stake (PoS) are employed, typically giving users voting rights and allocating block rewards based on users’ investment in computing resources or economic stake.

Instead of relying on computational power or participants’ economic stake to maintain the network’s integrity, layer-1 Proof of Personhood (PoP) networks leverage human existence for identity verification to achieve accountability, transparency, and Sybil resistance.

Therefore, PoP is an anti-Sybil attack blockchain mechanism that verifies an individual’s digital identity using their unique attributes and features, allowing users to retain control of their data. Also referred to as Proof of Existence (PoE) or Proof of Human Existence (PoHE), this concept allows individuals to verify a digital document’s existence without exposing its contents or relying on trusted intermediaries.

Put simply, PoP mechanisms verify that every individual in a decentralized network is unique and has one and only one identity. It ensures that every participant holds an equal level of influence regarding the network’s consensus, decision-making, voting rights, and reward distribution. Coupled with establishing Sybil resistance, this fosters a fair and democratic decentralized network.

How Does It Work?

PoP networks are based on two key components – personhood and decentralization. The concept of personhood implies that PoP network participants must assert their humanness (personhood) and uniqueness via means like community verification and blockchain-based biometric data. Unlike conventional identity verification mechanisms, PoP networks typically rely on decentralized, unique human recognition processes to verify user identities, eliminating susceptibility to impersonation and identity fraud.

In addition, layer-1 PoP networks leverage a network of nodes to verify an individual’s identity, as opposed to a trusted third-party or centralized authority. Utilizing decentralized identity verification systems significantly lowers data breach risks while granting users control over their data.

Popular examples of PoP protocols include Humanode, Idena, Gitcoin Passport, and Worldcoin.

What are PoP use cases?

Besides facilitating decentralized identity verification in industries like banking, voting systems, and healthcare, some of the potential use cases of PoP protocols include:

• Self-sovereign identity (SSI) – PoP networks facilitate SSI, allowing individuals to own and control how and where their data, including personally identifiable information, is used.
• Democratic governance – PoP protocols can verify the identity of voters in a democratic system without disclosing personal information or requiring centralized authority.
• Universal basic income (UBI) – PoE systems can potentially confirm the identities of eligible UBI recipients, allowing secure and fair distribution of basic income. 
• Public goods funding – These protocols can unlock transparency, accountability, and security of funding of public goods, such as public infrastructure, open-source software, and public services.