Port is a sophisticated identity verification platform that employs Public Key Infrastructure (PKI), relying on authenticated passport signatures to ensure secure on-chain Sybil protection. This technology finds applications in various domains like voting, quadratic funding, UBI airdrops, and one-per-person limit orders. It also facilitates off-chain verification, allowing users to selectively reveal personal data. Developed by the ZeroPass team, Port stands out for its secure, user-controlled identity verification mechanism, enhancing trust and security in digital interactions.