The public launch of Polygon ID comes 12 months after it was first launched in a closed-environment to a select group of builders. Polygon, a layer-2 scaling protocol for Ethereum, has launched a zero-knowledge decentralized identity solution to the public nearly a year after announcing its development. The Polygon ID service uses zero-knowledge proofs (ZK proofs) that use cryptographic techniques to allow users to verify their identity online without having their sensitive information passed or potentially stored with a third party.